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GHG reporting software — a living green facade on a corporate building, the organisation whose emissions the GHG Protocol makes a measured quantity
GHG reporting software · Every figure sourced · Verified 19 August 2026

GHG reporting software: the mechanics

Every platform on this market sells the same promise. The useful question is narrower: does it implement the GHG Protocol Corporate Standard, the 2004 document that UK SRS S2 names by title and year at paragraph 29(a)(ii) [1] [32].

This page works through what that standard requires, requirement by requirement, and turns each one into something you can ask a vendor to show you on a screen. It is not a ranking. The fuller vendor comparison lives on the carbon reporting software page.

Photo: Unsplash / Ricardo Gomez Angel
2004the standard UK SRS S2 names 15Scope 3 categories, each with a minimum boundary 26% the UK grid factor fell in one edition 55primary sources — all linked
01 · In plain English

What GHG reporting software actually has to do

Not dashboards. A number that survives being restated, and an audit trail that explains why it moved.

Almost every page on this subject compares features. Features are the easy part: any competent product can multiply an activity figure by an emission factor and draw a chart. The hard part is what happens eighteen months later, when the emission factor has been revised, an operating company has been sold, and somebody wants to know whether last year’s reduction was real.

The GHG Protocol Corporate Standard puts that requirement in an accounting principle rather than a technical annex. Its transparency principle reads, in full: “Address all relevant issues in a factual and coherent manner, based on a clear audit trail[1]. That is a data-architecture requirement written into a principle of accounting, and it is the single sentence that separates a reporting tool from a spreadsheet with a logo on it.

01
Hold the boundary, not just the data
Which legal entities are inside the inventory, on which consolidation approach, and what changed this year. UK SRS S2 goes further and requires Scope 1 and Scope 2 to be disaggregated between the consolidated accounting group and other investees — a requirement about the accounting boundary, not about emission factors, and the one most likely to defeat a spreadsheet.
02
Hold the factor, its edition and its basis
A stored figure of 1,240 tCO₂e is not a fact. It is the product of an activity figure, a factor table, an edition of that table, a definitional basis and an IPCC assessment report. Store only the product and you cannot restate the base year, which the standard requires you to be able to do.
03
Hold the policy, and apply it consistently
The base-year recalculation policy, the significance threshold you chose, the categories you excluded and why. All four are required reporting elements under Chapter 9 of the Corporate Standard, and none of them is a number a calculation engine produces.
04
Produce the disclosure the regime asks for
SECR wants Scope 1, Scope 2, kWh, an intensity ratio, a methodology statement and comparatives, in the directors’ report. UK SRS S2 wants location-based Scope 2 and a named list of the Scope 3 categories included. These are different shapes of the same dataset.
SOURCE: the five accounting principles and the Chapter 9 required reporting elements, GHG Protocol Corporate Standard (Revised Edition), 2004 [1][2]; the disaggregation and Scope 2 requirements, UK SRS S2 para 29(a)(iv) and 29(a)(v) [32]; the SECR disclosure list, SI 2008/410 Schedule 7 paras 20D, 20F, 20G and 20H [26][27].

Everything else on this page is that argument in detail, worked through the documents themselves. If you would rather start from the procurement end — budgets, shortlists, implementation time and the platforms themselves — the carbon reporting software comparison is the page for that, and it reviews seventeen platforms. This one is about what any of them must be able to do before the comparison is worth having.

The sentence to take away

A greenhouse gas figure is only as good as the record of how it was made. Software that stores the answer and not the working cannot restate a base year, cannot survive assurance, and cannot tell a definitional change apart from a decarbonisation trend.

GHG accounting software and the GHG Protocol Corporate Standard — a glasshouse lattice, the 2004 architecture every platform implements Photo: Unsplash / Paula Prekopova
02 · The document

GHG accounting software implements a standard written in 2004

Amended twice, cited by name in UK law’s voluntary standard, and currently being rewritten from scratch.

The document is The Greenhouse Gas Protocol: A Corporate Accounting and Reporting Standard, Revised Edition, published by the World Resources Institute and the World Business Council for Sustainable Development in March 2004 [1]. It has been amended twice in twenty-two years: the February 2013 amendment added nitrogen trifluoride to the gases that must be accounted for [3], and the January 2015 Scope 2 Guidance rewrote how purchased energy is accounted for [4].

The five principles, in the standard’s own words

Relevance “Ensure the GHG inventory appropriately reflects the GHG emissions of the company and serves the decision-making needs of users.”
Completeness “Account for and report on all GHG emission sources and activities within the chosen inventory boundary.”
Consistency “Use consistent methodologies to allow for meaningful comparisons of emissions over time.”
Transparency “Address all relevant issues in a factual and coherent manner, based on a clear audit trail.”
Accuracy “Ensure that the quantification of GHG emissions is systematically neither over nor under actual emissions.”
SOURCE: GHG Protocol Corporate Standard (Revised Edition), Chapter 1, WRI/WBCSD, March 2004 [1]. Quoted verbatim.

Scope 3 is described as optional, in the text UK SRS S2 names

This is the fact most likely to surprise a buyer who has been reading vendor material, and it is checkable in four lines of Chapter 4. The standard defines the three scopes as follows — verbatim [1]:

Scope 1 — “Direct GHG emissions occur from sources that are owned or controlled by the company.”

Scope 2 — “GHG emissions from the generation of purchased electricity consumed by the company.”

Scope 3 — “An optional reporting category that allows for the treatment of all other indirect emissions.”

GHG Protocol Corporate Accounting and Reporting Standard, Revised Edition, Chapter 4 — “Setting Operational Boundaries”, 2004

Two things follow, and both are worth being exact about. Scope 3 became a required part of an inventory only through the separate Corporate Value Chain (Scope 3) Standard of 2011 [5], which is a different document with its own conformance requirements; and it is proposed to become mandatory in the consolidated standard now in draft [12] — a proposal, in a progress update, not a rule. Anyone telling you “the GHG Protocol requires Scope 3” is compressing three documents and a draft into one sentence.

The second follows from the same paragraph: Scope 2 in the 2004 text covers purchased electricity only. Steam, heat and cooling were folded in explicitly by the 2015 Guidance. A tool that treats district heating as Scope 2 is right, but it is right because of the amendment, not the base standard.

Six gases, then seven

The 2004 Revised Edition covers six gases: CO₂, CH₄, N₂O, HFCs, PFCs and SF₆. Nitrogen trifluoride was added by the February 2013 amendment, which requires companies to “account for and report the emissions of all the GHGs required by the UNFCCC/Kyoto Protocol” and lists all seven [3]. GHG Protocol’s own landing page says the standard covers seven gases without noting that the seventh arrived nine years later — true of the standard as amended, not of the 2004 document. If your software’s gas list stops at six, it is implementing the unamended text.

Chapter 9 — the list that is really a software specification

Chapter 9 sets out what a public GHG emissions report shall contain. Read as a procurement document rather than an accounting one, it is the most useful page in the standard, because at least four of its nine required elements are things a tool either models or cannot produce at all [2].

Required element — Chapter 9, verbatimWhat it demands of software
“An outline of the organizational boundaries chosen, including the chosen consolidation approach.” An entity register with a consolidation basis, not a list of sites
“An outline of the operational boundaries chosen, and if scope 3 is included, a list specifying which types of activities are covered.” Category-level inclusion state, stored and reportable
“Total scope 1 and 2 emissions independent of any GHG trades such as sales, purchases, transfers, or banking of allowances.” Gross emissions and offsets in separate ledgers — never one netted figure
“Emissions data for all six GHGs separately … in metric tonnes and in tonnes of CO2 equivalent.” Gas-level storage, not a CO₂e total; seven gases since 2013 [3]
“Year chosen as base year, and an emissions profile over time that is consistent with and clarifies the chosen policy for making base year emissions recalculations.” A restatement engine, and the policy stored as data
“Appropriate context for any significant emissions changes that trigger base year emissions recalculation (acquisitions/divestitures, outsourcing/insourcing, changes in reporting boundaries or calculation methodologies, etc.).” A change log attached to the figure, with a reason field
“Emissions data for direct CO2 emissions from biologically sequestered carbon … reported separately from the scopes.” A biogenic line that sits outside the scope totals
“Methodologies used to calculate or measure emissions, providing a reference or link to any calculation tools used.” Method provenance per figure, exportable
“Any specific exclusions of sources, facilities, and / or operations.” An exclusion register with justifications
SOURCE: GHG Protocol Corporate Standard, Chapter 9 — “Reporting GHG Emissions”, required information, WRI/WBCSD 2004 [2]. Left column verbatim; right column is this page’s reading of it. Chapter 9 names six gases because it is 2004 text; the 2013 amendment [3] adds NF₃ to what must be accounted for.

Three of those elements are worth pausing on, because they are the ones tools most often get wrong. Gross totals independent of any GHG trades means offsets and allowances cannot be netted into a scope total — they belong in a separate ledger, and Chapter 9 lists them among the optional information. Biogenic CO₂ reported separately from the scopes means a tool that folds biomass combustion into Scope 1 is producing a non-conforming figure. And the base-year recalculation policy is a stored decision, not a calculation — which brings us, later, to the fact that there is no numeric threshold to store.

If you want the standard itself explained rather than its software consequences, the GHG Protocol page covers the framework, and the scopes page defines the three categories with worked examples.

GHG reporting software and organisational boundaries — a tree growing through corporate concrete, equity share against financial and operational control Photo: Unsplash / Alexander Abero
03 · The boundary

Who is inside the number, and on what basis

The boundary is a software configuration, not a policy PDF. Getting it wrong changes every figure downstream and nothing on the dashboard.

Chapter 3 of the Corporate Standard sets organisational boundaries, and offers a company equity share or control. A company choosing control then chooses financial control or operational control. That nesting matters, and most summaries flatten it into three parallel options [1].

Equity share The company accounts for GHG emissions “according to its share of equity in the operation”. Reflects economic interest, and produces fractional emissions from joint ventures and associates.
Financial control The company “has the ability to direct the financial and operating policies of the latter with a view to gaining economic benefits” from its activities. Tends to follow the financial-statement consolidation.
Operational control The company “has the full authority to introduce and implement its operating policies at the operation”. Tends to follow who runs the site, which is not always who owns it.
SOURCE: GHG Protocol Corporate Standard, Chapter 3 — “Setting Organizational Boundaries”, WRI/WBCSD 2004 [1]. Definitions verbatim.

The choice is not cosmetic. A group with material joint ventures reports a materially different Scope 1 under equity share than under operational control, and the difference is not an error in either case. What the standard requires is that you state which approach you chose — it is the first item in Chapter 9’s required list — and apply it consistently.

And the approach itself may be about to change
The draft Corporate Standard Phase 1 progress update of December 2025 proposes eliminating the equity share approach altogether, with financial control as the primary basis tied to financial-statement consolidation. That document carries its own disclaimer — “All revisions under development … are subject to change and should not be construed as final nor relied upon as advice” — and no consolidated draft standard has been published for consultation. Treat it as a reason to ask whether your platform can re-run a boundary, not as a reason to change one. SOURCE: Corporate Standard Phase 1 Progress Update, GHG Protocol, December 2025 [12]

The UK SRS S2 requirement that defeats spreadsheets

UK SRS S2 adds a requirement the Corporate Standard does not have. Paragraph 29(a)(iv) requires an entity, for Scope 1 and Scope 2, to disaggregate emissions between “the consolidated accounting group” and “other investees excluded from paragraph 29(a)(iv)(1)” — associates, joint ventures and unconsolidated subsidiaries [32].

That is a requirement about the accounting boundary, not about emission factors, and it is the one that separates a tool with an entity model from a tool with a site list. You cannot produce it by tagging facilities. You produce it by knowing, for each source of emissions, which legal entity owns it and how that entity is treated in the consolidated accounts.

The checker below runs that logic against the standard’s own definitions. Nothing is sent anywhere; the whole thing runs in your browser.

03b · Boundary checker

Which entities land inside your inventory?

Pick a consolidation approach and a relationship, and the checker works out what goes in, on what basis, and what UK SRS S2 forces you to split out.

Answer for one investee at a time. A group with several relationships should run it once for each, because the approach applies uniformly but the outcome does not.

The output is an account of what two published documents require: Chapter 3 of the Corporate Standard for the consolidation basis, and UK SRS S2 paragraph 29(a)(iv) for the disaggregation. It is not advice about your accounts.

Boundary and disaggregation checker Ch. 3 / 29(a)(iv)
SOURCE: GHG Protocol Corporate Standard, Chapter 3 [1]; UK SRS S2 paragraph 29(a)(iv) [32]
GHG emissions software and Scope 2 dual reporting — wind turbines above a flowering field, the location-based and market-based methods reported side by side Photo: Unsplash / Zbynek Burival
04 · Two numbers

GHG emissions software and the Scope 2 that is not one number

The 2015 Guidance made Scope 2 a pair. Half the market still reports a single figure and does not say which one it is.

The Scope 2 Guidance of January 2015 is described by GHG Protocol as “the most significant amendment to the Corporate Accounting and Reporting Standard since its inception” [4]. Because it is an amendment, its requirements are requirements of the Corporate Standard — which means they are requirements of UK SRS S2, which names that standard.

“Companies with any operations in markets providing product or supplier-specific data in the form of contractual instruments shall report scope 2 emissions in two ways and label each result according to the method: one based on the location-based method, and one based on the market-based method.”

“If companies only have operations in markets without product or supplier-specific data, then only one scope 2 result shall be reported, based on the location-based method.”

GHG Protocol Scope 2 Guidance, section 1.5.1 and Table 1.1, WRI/WBCSD, January 2015

Both halves matter, and the second is almost never quoted. Market-based reporting is not universally required. A company with no contractual instruments reports one number, and a platform that forces a market-based figure into an empty market is producing a number the standard did not ask for. The methods themselves are defined tightly:

Location-based “Reflects the average emissions intensity of grids on which energy consumption occurs (using mostly grid-average emission factor data).” In the UK this is the DESNZ grid factor. UK SRS S2 paragraph 29(a)(v) makes this one mandatory — the market-based figure is supplementary, never a substitute.
Market-based “Reflects emissions from electricity that companies have purposefully chosen (or their lack of choice). It derives emission factors from contractual instruments.” Requires contractual instruments that meet eight quality criteria, and a residual mix for whatever is left over — or a disclosure that no residual mix is available.

The eight quality criteria

All contractual instruments used in the market-based method shall meet eight criteria. The first five are quoted here from GHG Protocol’s own executive summary; criteria six to eight are set out in prose below because they were read from two concordant reproductions of Table 7.1 rather than from the Guidance PDF itself, and this page marks that difference rather than hiding it.

01 “Convey the direct GHG emission rate attribute associated with the unit of electricity produced.”
02 “Be the only instruments that carry the GHG emission rate attribute claim associated with that quantity of electricity generation.”
03 “Be tracked and redeemed, retired, or canceled by or on behalf of the reporting entity.”
04 “Be issued and redeemed as close as possible to the period of energy consumption to which the instrument is applied.”
05 “Be sourced from the same market in which the reporting entity’s electricity-consuming operations are located and to which the instrument is applied.”
06–08 Three further criteria cover utility and supplier-specific emission factors (they must be calculated on delivered electricity, with sold-off attributes characterised at the residual mix), direct contracts and on-site generation (the instruments must be transferred to the reporting entity only, with no parallel claim issued to another end user), and the residual mix itself — which must be made available for consumer Scope 2 calculations, “or its absence shall be disclosed by the reporting entity”.
SOURCE: criteria 1–5 verbatim from the GHG Protocol Scope 2 Guidance Executive Summary [4]. Criteria 6–8 from Table 7.1 of the Guidance as reproduced concordantly by CDP’s Corporate Questionnaire v12.0 (20 April 2026) and by GHG Protocol’s own Scope 2 revision guide framework, 16 December 2024 [17]; Table 7.1 in the Guidance PDF itself was not read for this page.

Criterion 3 is the one that turns a procurement fact into a software fact. An instrument must be tracked and redeemed, retired, or cancelled on your behalf. In the UK that instrument is the REGO, issued and redeemed through Ofgem’s register [55] — and a REGO conveys an attribute claim, not an emissions reduction, so it is not a carbon offset. A certificate you have bought but not retired is not evidence of anything, and a platform that lets you enter “100% renewable” as a percentage rather than as retired instruments with identifiers cannot demonstrate criterion 3 to an assurer.

The UK has no official residual mix — and that is not a gap in your software

The market-based method needs a factor for whatever electricity you did not claim with instruments. That is the residual mix. In the UK, there is no official one.

AIB Great Britain residual mix, 2025 vintage280.64 gCO₂/kWh
Untracked share it rests on58.16%
Published byAssociation of Issuing Bodies, 26 May 2026
Adopted by a UK authorityNo
Residual mix in the DESNZ conversion factorsNone — the term does not appear
OfgemPublishes fuel mix disclosure, not a residual mix factor
DESNZ residual fuel mix, to 31 Mar 2026Percentages only, no CO₂ intensity

The AIB does publish a Great Britain figure, and it is the de facto convention because it is the only published GB residual-mix intensity. But the AIB says so itself: “the official residual mixes for each country are in principle published by the respective national authorities” [49], and no UK authority adopts it. Ofgem operates a fuel mix disclosure regime, which is a different instrument [50].

The two official-adjacent pictures disagree, and that is the honest story
The AIB’s GB residual mix rests on a 58.16% untracked share and puts gas at 51.29%. DESNZ’s residual fuel mix, for roughly the same period, puts gas at 65.3%. They are built for different purposes over different periods, and they produce materially different pictures of the same thing. That disagreement is why there is no official UK residual mix, and it is why criterion 8’s alternative — disclose that a residual mix is not available — is live for most UK reporters rather than exotic. SOURCE: European Residual Mixes 2025, AIB, 26 May 2026, Table 2 [49]; Fuel mix disclosure data table 2025, DESNZ [51]

What that means for a buyer is specific: ask to see the disclosure, not the number. A platform that silently substitutes a grid average for a residual mix has made an accounting choice on your behalf and left no record of it.

04b · Scope 2 checker

How many Scope 2 numbers must you report?

One question about your market, one about your instruments, and the Guidance answers it — including the disclosure most UK reporters owe.

The checker computes from section 1.5.1 and the eight quality criteria, and adds the UK SRS S2 paragraph 29(a)(v) overlay where it applies. Nothing is sent anywhere.

Read the verdict as an account of what two documents require of a disclosure. It is not a calculation of your emissions and it is not advice.

Scope 2 dual-reporting checker S2 Guidance 1.5.1
SOURCE: GHG Protocol Scope 2 Guidance, section 1.5.1, Table 1.1 and the eight quality criteria [4][17]; UK SRS S2 paragraph 29(a)(v) [32]
Greenhouse gas reporting software and the 15 Scope 3 categories — hands holding a seedling, the value chain the minimum boundary defines Photo: Unsplash / Nikola Jovanović
05 · The value chain

Greenhouse gas reporting software and the 15 Scope 3 categories

Fifteen categories, each with a minimum boundary. Report by category or you have not reported.

The Corporate Value Chain (Scope 3) Accounting and Reporting Standard, published September 2011, is a separate document from the Corporate Standard and carries its own requirements [5]. Two of them, from Table 3.1, verbatim:

“Companies shall account for all scope 3 emissions and disclose and justify any exclusions.”

“Companies shall account for emissions from each scope 3 category according to the minimum boundaries listed in table 5.4.”

Corporate Value Chain (Scope 3) Accounting and Reporting Standard, Table 3.1, WRI/WBCSD, September 2011

The categories are numbered and named, and the names are part of the standard. Category 3 in particular carries a parenthetical that vendors routinely drop — and the parenthetical is what stops it double-counting Scopes 1 and 2.

Upstream 1Purchased goods and services
Upstream 2Capital goods
Upstream 3Fuel- and energy-related activities (not included in scope 1 or scope 2)
Upstream 4Upstream transportation and distribution
Upstream 5Waste generated in operations
Upstream 6Business travel
Upstream 7Employee commuting
Upstream 8Upstream leased assets
Downstream 9Downstream transportation and distribution
Downstream 10Processing of sold products
Downstream 11Use of sold products
Downstream 12End-of-life treatment of sold products
Downstream 13Downstream leased assets
Downstream 14Franchises
Downstream 15Investments
SOURCE: Corporate Value Chain (Scope 3) Standard, Chapter 5, WRI/WBCSD 2011 [5]. Category names verbatim, including category 3’s parenthetical.

Minimum boundary is the concept that makes the categories tractable

Without a boundary rule, tracing a value chain runs indefinitely: your supplier’s supplier’s supplier. Table 5.4 fixes that. Its stated purpose, verbatim: it “identifies the minimum boundaries of each scope 3 category in order to standardize the boundaries of each category and help companies understand which activities should be accounted for” [5]. Going beyond the minimum boundary is optional; falling short of it is an exclusion, and exclusions must be disclosed and justified.

For software this is a schema question, not a calculation question. A tool that models Scope 3 as one bucket cannot state which categories it includes, cannot record an exclusion with a justification, and therefore cannot produce a disclosure that satisfies either the 2011 standard or UK SRS S2 paragraph 29(a)(vi)(1) — which requires an entity to disclose the categories included in its measure, by reference to that standard’s own list [32].

Specificity is not accuracy — and the Protocol says so

Almost every platform on this market sells the same upgrade path: get off spend-based estimates, onto supplier-specific data, and your Scope 3 gets better. The Scope 3 Technical Guidance says something more careful, and it says it in a box:

“Even though the supplier-specific and hybrid methods are more specific to the individual supplier than the average-data and spend-based methods, they may not produce results that are a more accurate reflection of the product’s contribution to the reporting company’s scope 3 emissions.”

Technical Guidance for Calculating Scope 3 Emissions, version 1.0, Box 1.1, pp. 22–23, WRI/WBCSD, 2013

The Guidance goes on to note that supplier data “may actually be less accurate than industry-average data”, because of allocation complexity and reliability. The Guidance’s own Table IV ranks levels of data — product-level, then activity or process level, then facility, business unit and corporate — explicitly “in order of specificity”, which is not a synonym for quality [6].

None of that is an argument for staying on spend-based data. It is an argument for a platform that records which method produced each category figure and lets you defend the choice, rather than one that treats a supplier-data percentage as a score to maximise.

Deeper on the categories themselves: the Scope 3 emissions page works through all fifteen with UK examples, and Scope 3 under UK SRS covers the relief that lost its time limit.

GHG reporting software and emission factor versions — an Only Leave Your Footprints sign, a printed instruction that dates the moment the factors change Photo: Unsplash / Nick Fewings
06 · The factors

Emission factors are versioned data, and most tools store the answer instead

The UK grid factor fell 26% in one edition, and most of that fall was a change in how it is calculated.

The UK government publishes conversion factors annually. The current edition is Greenhouse gas reporting: conversion factors 2026, published by the Department for Energy Security and Net Zero on 11 June 2026 and last updated 31 July 2026 [18]. It ships as a full-set spreadsheet, a flat file for automatic processing, a 152-page methodology report and an 18-page major changes report.

Its own statement of scope is narrow and worth quoting, because it is the sentence that makes these factors the right ones for a UK reporter and the wrong ones for a global consolidation: they “enable users to calculate and report greenhouse gas emissions from their UK activities in 2026”, and are suitable for “UK-based organisations of all sizes” and “International organisations reporting on their UK operations” [18].

What changed in 2026

Headline movements, 2025 edition → 2026 edition
UK electricity−26% — and see below, most of it is not decarbonisation
Electric cars and vans−12% to −37%
London Underground−44% / −45%
International rail+154% / +156%
Refrigerant R-511ACorrected from 6.9 to 0 kgCO₂e/kg
Delivery-van plug-in hybrids+16%
SOURCE: Conversion factors 2026: major changes, DESNZ, entry 17 and adjacent entries [20].

A 26% fall in the grid factor looks like a decarbonisation story. Most of it is not. The major changes report explains why, verbatim [20]:

“In previous updates, the data used in the calculations lagged the publication year by two years. In this year’s update, the lag has been reduced to one year using latest Energy Trends statistics. As a result, the reported change since the 2025 publication reflects two years’ worth of changes in the electricity grid mix and grid losses, rather than the usual one year.”

“Changes in the grid mix from 2023-2024 had a bigger impact (-16 percentage points) than the incorporation of an additional years’ worth of data (changes in the grid mix from 2024-2025 accounted for -3pp). The remaining 6-7pp of the decrease is due to methodological changes, improvements and corrections described above.”

Conversion factors 2026: major changes, DESNZ, entry 17

The report also cites improved import and export accounting, and “correcting the previous methodology to resolve a small double-counting issue that affected autogenerators”. So of a 26-point fall, roughly six or seven points are definitional and a further three are simply a year of data arriving early.

The trap, in one table

2026 edition, Table 9 — kgCO₂e per kWhGeneratedConsumed (incl. losses)
Total CO₂e0.130960.14396
CO₂0.129430.14227
CH₄0.000670.00074
N₂O0.000860.00095
Transmission & distribution losses alone0.01299
SOURCE: 2026 GHG conversion factors methodology report, DESNZ, Table 9 — “Base electricity generation emissions factors (including imported electricity)”, 2025 data year applied to 2026 reporting [19]. Confirmed 19 August 2026 against the full-set spreadsheet, which publishes the generated factor (0.13096, ‘UK electricity’) and the transmission and distribution factor (0.01299) as separate Scope 2 and Scope 3 entries, and no combined consumed figure at all. Consumed is generated ÷ (1 − losses), not generated plus losses — which is why it reads 0.14396 and not 0.14395.

Here is the trap, and it is the reason this chapter exists. The 2025 edition’s equivalent table is titled “excluding imported electricity” and totals 0.18882. The 2026 table is titled “including imported electricity” and totals 0.13096. They are not like-for-like. Compute the change naively and you get −31%; the government prints −26%, because it compared on a consistent basis.

What this means for software, precisely

A tool that stores a computed tCO₂e figure without also storing the factor table, its edition and its definitional basis cannot tell those two numbers apart. It will present a change in what the factor measures as a change in what your company emitted. Ask a vendor to show you the factor version stamped on a specific figure from two years ago. If the answer is a screenshot of a settings page rather than a field on the record, the tool stores the answer and not the working.

The cadence compounds this. Factors are updated annually — the 2025 edition was published 10 June 2025, the 2024 edition on 30 October 2024 and the 2023 edition on 28 June 2023 [21]. The publication month moves, so a process that assumes a June refresh will be wrong roughly one year in three.

GHG accounting software and global warming potential — a single leaf held in an open hand, one unit weighted by the assessment report you chose Photo: Unsplash / @name_ gravity
07 · The weighting

Global warming potential: AR6 is recommended, not required

And a UK company using the government’s own factors is on AR5. That is a divergence, not a defect — but it has to be handled explicitly.

A tonne of methane is not a tonne of CO₂e until you multiply it by a global warming potential, and which GWP you use depends on which IPCC assessment report you chose. The GHG Protocol’s requirement, from the February 2013 amendment, is narrower than most people assume — verbatim: companies “shall use 100-year GWP values from the IPCC” and “shall use GWPs from a single Assessment Report for any one inventory, where possible” [3].

The requirement does not name an assessment report. The recommendation does: GHG Protocol’s Global Warming Potential Values, version 2.0 of 7 August 2024, tabulates AR4, AR5 and AR6 and says “the use of the latest values (AR6) is recommended”, acknowledging that AR4 and AR5 values “are sometimes used for inventory and reporting purposes” [8].

The UK government has not followed the recommendation. The 2026 conversion factors methodology report states its basis verbatim: “Global Warming Potential (GWP) factors from the Intergovernmental Panel on Climate Change (IPCC)’s fifth assessment report (IPCC, 2014) (GWP for CH4 = 28, GWP for N2O = 265)” [19]. Some refrigerants not covered by AR5 take values from AR6 or from earlier reports.

GHG Protocol requirement100-year horizon; one assessment report per inventory
GHG Protocol recommendationAR6 — recommended, not required
UK conversion factors, 2026 editionAR5
Methane, AR5 100-year, excluding feedbacks28
Nitrous oxide, AR5 100-year, excluding feedbacks265
Base year and current yearMust use the same GWP values

Two precision points, because this is where imprecise pages go wrong. First, 28 and 265 are the AR5 100-year values excluding climate–carbon feedbacks; AR5 also publishes higher values including feedbacks, where methane is 34. Saying “AR5” without the qualifier is not precise enough to reproduce a calculation.

Second, GHG Protocol’s technical assistance is explicit that companies “should use the same GWP values for the current inventory period and the base year to maintain consistency and comparability across time and scopes”. That is a restatement trigger in waiting: the day you move from AR5 to AR6, your base year has to move with you, or your trend line stops meaning anything.

The question this makes worth asking on a demo
“Show me a 2023 figure, and tell me which assessment report’s GWP values produced it.” A platform that cannot answer at the level of the individual figure cannot move you from AR5 to AR6 without either invalidating your history or quietly rewriting it. Neither is acceptable to an assurer, and the second is worse. Derived from GHG Protocol’s single-assessment-report requirement [3] and the base-year consistency guidance [8]
08 · Restatement

Base year, restatement, and the 5% rule that does not exist

There is no GHG Protocol significance threshold. You choose one, you disclose it, and your software has to apply it consistently for years.

Restatement is the least glamorous thing a GHG platform does and the thing that decides whether its output is worth anything after year three. The rule comes from Chapter 5 of the Corporate Standard, and GHG Protocol’s own 2019 Scope 1 & 2 GHG Inventory Guidance handbook states it plainly [7]:

A company “may be required to recalculate its baseline year inventory whenever the following happens: Significant changes in the structure of the reporting company; Significant changes in the calculation methodology; [and] Discovery of significant errors or smaller errors that are collectively significant.

“The GHG Protocol Corporate Standard does not have a set definition for ‘significant’, however a company should determine its own significance threshold (i.e. 2 percent) to define when changes, in aggregate, should trigger recalculation of the baseline year inventory.”

Scope 1 & 2 GHG Inventory Guidance, GHG Protocol, November 2019

Read that second paragraph carefully, because a great deal of marketing depends on nobody doing so. There is no GHG Protocol significance threshold. The 2% in that sentence is GHG Protocol’s own worked example, introduced with “i.e.”. The widely-quoted “5% rule” does not appear in any GHG Protocol document this page could locate. What the standard actually requires is that the company sets its own threshold and discloses it — Chapter 9 lists the base-year recalculation policy among the required reporting elements [2].

The distinction that decides every case: structural or organic

Structural — recalculate The company changed shape, or the method did. Acquisitions and divestitures. Outsourcing and insourcing. Changes in reporting boundaries. Changes in calculation methodology. Discovery of significant errors, or smaller errors that are collectively significant. Each of these makes the base year and the current year measure different things.
Organic — do not recalculate The company is the same shape and did something different. Opening or closing a facility you built or shut. Growing or shrinking output. Actually reducing emissions. These are the changes the trend line exists to show, and recalculating them away destroys the very comparison the base year is for.

An emission factor revision sits awkwardly across that line, and it is worth being explicit rather than glib. A revision that changes what the factor measures — the 2026 grid factor’s move to an including-imports basis, say — is a change in calculation methodology. A revision that reflects a genuinely different grid is not. Chapter 9 requires you to give “appropriate context” for any significant change that triggers a recalculation either way, which is a documentation requirement your platform either supports or leaves to a Word file nobody can find in 2029.

The checker below works a change through that logic, using the triggers the 2019 Guidance names and the threshold you set yourself.

08b · Restatement checker

Does this change trigger a base-year recalculation?

Pick what changed and how big it was against your own threshold. The checker applies the 2019 Guidance triggers and tells you what Chapter 9 then requires you to disclose.

The threshold is yours, not the tool’s. The checker asks for it rather than assuming one, because assuming one is the error this chapter exists to correct.

Nothing is sent anywhere. The verdict is an account of what two published documents require, not advice about your inventory.

Base-year restatement checker Ch. 5 / Ch. 9
SOURCE: recalculation triggers and the absence of a set definition of “significant”, Scope 1 & 2 GHG Inventory Guidance, GHG Protocol, November 2019 [7]; required reporting on the policy and on context for changes, Corporate Standard Chapter 9 [2]
GHG reporting software and the UK regimes — offshore wind turbines, the five places a UK greenhouse gas number can legally land Photo: Unsplash / Nicholas Doherty
09 · The regimes

Where a UK greenhouse gas number legally lands

Five regimes, one dataset, and only two of them are in force. Knowing which is which is most of the procurement decision.

Vendors sell against a blur of acronyms. The blur hides the only distinction that matters for a buyer: which of these obliges you to do anything today.

RegimeStatus, 19 August 2026Where the number goes
SECR In force. Statutory. Mandatory for financial years beginning on or after 1 April 2019 Directors’ report; a standalone energy and carbon report for LLPs
UK SRS S1 / S2 Published 25 February 2026. Voluntary. No effective date. No entity is required to apply them Nowhere statutory yet
FCA CP26/5 Consulted. Closed 20 March 2026. No policy statement published as at 19 August 2026 Proposed: listed issuers’ annual financial report
ESOS In force. Statutory. Mandatory. Phase 4 notification deadline 5 December 2027 ESOS report and notification to the Environment Agency, plus an action plan
EU CSRD / ESRS In force in the EU; scope narrowed by Omnibus I, Directive (EU) 2026/470, in force 18 March 2026 The EU management report of the in-scope EU entity
SOURCE: SECR, SI 2008/410 Schedule 7 Parts 7 and 7A as inserted by SI 2018/1155 [22][23][24]; UK SRS, GOV.UK guidance and the published standards [31][34]; FCA CP26/5 and the FCA’s reporting-requirements page, both last modified 5 June 2026 [36][37]; ESOS phase 4 guidance, Environment Agency, updated 3 August 2026 [38]; Directive (EU) 2026/470 [53].

Two of the five oblige you today, and they oblige different things of different companies. SECR is a GHG reporting regime. ESOS is not — it is an energy audit regime, and there is no greenhouse gas emissions reporting requirement in it at all. The only link the Environment Agency’s guidance draws runs the other way: “Systems in place to collect and audit energy consumption to meet ESOS obligations … can help organisations to meet their SECR requirements” [38] [39].

ESOS also moved recently, which is worth knowing before accepting a vendor’s account of it. The Energy Savings Opportunity Scheme (Amendment) Regulations 2026, SI 2026/701, came into force on 22 July 2026 [40]. They remove Display Energy Certificates and Green Deal Assessments as alternative compliance routes, extend ISO 50001 deemed compliance, and insert a new regulation 33A exempting undertakings with zero kWh of total energy consumption. None of that changes the point above: ESOS still asks for energy audits, not a greenhouse gas disclosure.

“Large” means different things in different regimes

This is where a procurement conversation usually goes wrong, because the two live UK regimes use different tests with different logic and different numbers.

SECR — a 2-of-3 test Turnover £36m · balance sheet total £18m · 250 employees Framed as an exemption: a company is out if it meets two or more of those limits, and in if it exceeds two or more. Schedule 7 paragraph 20B.
ESOS — an OR/AND test 250 employees or (turnover over £44m and balance sheet total over £38m) The employee limb stands alone; the financial limbs are conjunctive. Qualification date for Phase 4 is 31 December 2026.

And there is now a band that is medium-sized for accounts and large for SECR

On 6 April 2025 the Companies (Accounts and Reports) (Amendment and Transitional Provision) Regulations 2024 raised the Companies Act medium-sized thresholds: turnover from £36m to £54m and balance sheet total from £18m to £27m, with employees unchanged at 250 [28].

It did not move SECR. Schedule 7 paragraph 20B has always carried its own table of figures rather than cross-referring to section 465 of the Companies Act, so the uplift moved section 465 and left 20B standing at £36m / £18m / 250 [25]. The Explanatory Memorandum says so in terms: these regulations “do not affect the streamlined energy and carbon reporting (‘SECR’) requirements”, with the consequence that “qualifying as an unquoted company or LLP required to comply with SECR requirements will no longer be aligned with qualifying as an unquoted large company or LLP under the Companies Act 2006” [29].

The practical consequence, and it is a live one

For financial years beginning on or after 6 April 2025 there is a band of companies — roughly £36m to £54m of turnover — that have become medium-sized for accounts purposes while remaining in scope for SECR. If your finance team has told you the company “dropped below the threshold”, check which threshold they meant. Two different instruments, two different tables, one of which did not move.

For UK groups with EU operations, the CSRD position narrowed sharply in 2026: the amended scope test is net turnover over €450m and more than 1,000 employees, and a third-country parent is caught only where it generates €450m of net turnover in the EU and has an EU subsidiary or branch above €200m [53] [54]. That is a materially smaller population than before Omnibus I. This page does not publish a figure for how many UK groups that is, because no post-Omnibus population figure is traceable to a single Commission document.

10 · The live obligation

What SECR actually makes you disclose

Seven paragraphs of a 2008 statutory instrument, and a guidance document that has not been updated since March 2019.

A point of order that trips up software procurement: the SECR obligations do not live in the 2018 regulations. SI 2018/1155 is an amending instrument. The operative requirements sit in Schedule 7 to SI 2008/410 — Part 7 for quoted companies, Part 7A for large unquoted companies and LLPs [22] [24]. If a vendor cites the 2018 SI for a substantive requirement, they are citing the wrong document.

20D(1) Annual emissions in tonnes CO₂e from activities for which the company is responsible involving the combustion of gas or the consumption of fuel for transport purposes.
20D(2) Annual emissions in tonnes CO₂e “resulting from the purchase of electricity by the company for its own use, including for the purposes of transport”.
20D(3) Aggregate annual quantity of energy consumed in kWh from the sources in (1) and (2).
20D(4) “If the company has in the financial year … taken any measures for the purpose of increasing the company’s energy efficiency, the report must contain a description of the principal measures taken for that purpose.”
20F “The directors’ report must state the methodologies used to calculate the information disclosed under paragraph 20D(1), (2) and (3).”
20G “The directors’ report must state at least one ratio which expresses the company’s annual emissions in relation to a quantifiable factor associated with the company’s activities.”
20H Except in the first year, the report must state the same information as disclosed in the report for the preceding financial year — the comparatives requirement.
SOURCE: SI 2008/410, Schedule 7 Part 7A, paragraphs 20D, 20F, 20G and 20H, as inserted by SI 2018/1155 [24][26][27]. Quoted verbatim from the in-force text. Quoted companies have the parallel requirements at paragraphs 15–18A of Part 7, on a global rather than UK basis, with the UK and offshore proportion stated separately.

Paragraph 20D(5) permits exclusion of emissions and energy consumed outside the UK, and 20D(6) is a practicability carve-out that requires you to state what has been omitted and why. Neither is a licence to leave things out quietly.

The 40,000 kWh exemption is an exemption from disclosure, not from the regime

Where a company consumed 40,000 kWh of energy or less in the United Kingdom during the period, the report need not contain the information — but the report must state that it is not disclosing, and why [26]. The company remains in scope. A platform whose SECR module simply produces nothing for a low-energy user has produced a non-compliant report, because the statement is itself a required disclosure.

What SECR does not require

SECR is not a Scope 3 regime, and the government guidance says so directly: “You are not required to report on other emissions associated with inputs into your company (such as emissions from your supply chain)” [30].

There is exactly one Scope 3 sliver inside the mandatory calculation for large unquoted companies, and it is a good test of whether a tool actually models SECR rather than approximating it. In: “Fuel used in personal/hire cars on business use (including fuel for which the organisation reimburses its employees following claims for business mileage)”. Out: “Fuel associated with taxi journeys your employees take where you do not operate the taxi firm”. Both sentences are from the same page of the same guidance.

The statutory guidance is seven years old
The Environmental reporting guidelines: including Streamlined Energy and Carbon Reporting requirements was first published on 12 June 2013 and last updated on 29 March 2019. That is the guidance for the regime vendors sell SECR modules against — unchanged through the 2024 company-size threshold uplift, through the publication of UK SRS, and through a single edition in which the grid factor fell by a quarter. Anything a platform tells you about SECR “best practice” after 2019 is the vendor’s view, not the government’s. SOURCE: GOV.UK publication page and the PDF itself, both dated 29 March 2019 [30]

If SECR is the whole of your obligation, the SECR requirements page is the fuller treatment, and the SECR reporting guide walks the disclosure itself.

11 · The voluntary standard

UK SRS S2 on greenhouse gases, quoted rather than summarised

Paragraph 29(a) is the most software-relevant paragraph in UK sustainability reporting, and almost nobody quotes it.

UK SRS S1 and UK SRS S2 were published on 25 February 2026. GOV.UK states the position in one sentence: “The standards are available for voluntary use, by any entity that chooses to do so” [34]. Neither standard contains an effective date, deliberately, and as at 19 August 2026 no legislation or regulation requires any UK entity to apply them.

Paragraph 29(a) of UK SRS S2 sets out what an entity applying the standard must do about greenhouse gases. Six sub-paragraphs; five consequences for software.

UK SRS S2 paragraph 29(a)What it means for a platform
29(a)(ii) — measure “in accordance with the Greenhouse Gas Protocol: A Corporate Accounting and Reporting Standard (2004) unless the entity is required … by a jurisdictional authority or an exchange … to use a different method” The 2004 standard is named, by title and year. The carve-out is a permanent provision of the main requirement, and is a different mechanism from the first-year transitional relief at paragraph C3
29(a)(iii) — disclose the measurement approach, inputs and assumptions, why they were chosen, and any changes made during the period and the reasons Method provenance and a change log, per figure, exportable as narrative
29(a)(iv) — disaggregate Scope 1 and Scope 2 between the consolidated accounting group and other investees An entity model tied to the accounting consolidation. Not achievable by tagging sites
29(a)(v) — disclose location-based Scope 2, and information about contractual instruments Location-based is the required figure. A tool that reports only a market-based number does not satisfy this
29(a)(vi)(1) — disclose the categories included, per the 2011 Scope 3 Standard’s list Category-level inclusion state, stored and reportable. Category transparency, not all-fifteen-or-nothing
29(a)(vi)(2) — additional information about financed emissions for asset management, commercial banking or insurance Attribution and allocation modelling, with the methodology disclosed — see below on what is and is not required
SOURCE: UK SRS S2 Climate-related Disclosures, paragraph 29(a), DBT, 25 February 2026 [32]. Left column quoted and abridged; right column is this page’s reading.

The two reliefs, and the asymmetry nobody states correctly

UK SRS S2 carries two transitional reliefs that bear on greenhouse gases, and the government response to the consultation is the authority on both [35].

What the UK changed, relief by relief
IFRS S2 para C4(a) — a first-year relief from using the GHG Protocol Corporate StandardUK SRS S2 para C3 — carried across, and it keeps its first-year limit
IFRS S2 — a Scope 3 relief limited to the first annual reporting periodUK SRS S2 para C4 — “the reference to the first annual reporting period has been removed for this relief. The availability of this relief will, instead, be specified in legislation or regulation”
SOURCE: Government response to the consultation on UK Sustainability Reporting Standards, Annex A, DBT, 25 February 2026 [35]. Second row quoted verbatim.

The consequence is a fact that almost nothing on this subject states: the Scope 3 relief in UK SRS S2 has no time limit and no instrument to give it one, because the legislation that would specify its availability does not exist. An entity applying UK SRS voluntarily today may omit Scope 3 entirely and still assert compliance with UK SRS S2.

That claim depends on paragraph 73A of UK SRS S1, which is asymmetric and is almost always quoted in its symmetric form:

“An entity making use of the provision in paragraph E3 of UK SRS S1 is not permitted to assert compliance with UK SRS S1 and shall disclose use of this provision instead. However, an entity making use of one or more of these three provisions is not prevented from asserting compliance with UK SRS S2, but it shall disclose its use of those provisions alongside its statement of compliance.”

UK SRS S1 General Requirements for Disclosure of Sustainability-related Financial Information, paragraph 73A, DBT, 25 February 2026 [33]

Stated standard by standard, because that is the only correct way to state it: using C3 or C4 costs you nothing. Using the climate-only relief at S1 paragraph E3 costs you the S1 compliance statement, while leaving the S2 statement available. Any page that compresses this into “taking a relief costs you your compliance statement” has lost the distinction that matters.

Financed emissions — PCAF is convention, not requirement

For asset managers, commercial banks and insurers, paragraph 29(a)(vi)(2) and paragraphs B58–B63A require additional information about financed emissions. What those paragraphs require is disclosure about methodology — for asset management, at B61, “the methodology used to calculate the financed emissions, including the method of allocation the entity used to attribute its share of emissions in relation to the size of investments”, with commercial banking and insurance mirroring it against gross exposure [32].

It does not prescribe an attribution formula and it names no provider. A full-document search of the published UK SRS S2 for “PCAF” and “Partnership for Carbon Accounting Financials” returns nothing. The PCAF standard exists and most firms use it — The Global GHG Accounting and Reporting Standard Part A: Financed Emissions, third edition, December 2025 [52] — but “UK SRS S2 requires PCAF” turns an implementation choice into a false normative claim.

One further detail worth knowing before treating “PCAF-aligned” as transitive to GHG Protocol conformance: PCAF’s own imprint records that only the 2020 first edition was reviewed by GHG Protocol, and that because “the GHG Protocol has since closed its Built on GHG Protocol review service”, the second-edition additions and “all new methodologies and guidance introduced in the December 2025 edition, have not yet been reviewed by the GHG Protocol”.

GHG emissions software and assurance readiness — hands cupping a fern frond, a figure held up to third-party verification Photo: Unsplash / Noah Buscher
12 · Assurance

The assurance standard changes on 15 December 2026

The only standard written specifically for a greenhouse gas statement is withdrawn that day, and the UK register that would replace part of it has not opened.

ISAE 3410, Assurance Engagements on Greenhouse Gas Statements, has been the IAASB’s dedicated GHG assurance standard since reports covering periods ending on or after 30 September 2013. The IAASB’s own page now states it plainly: “ISAE 3410 has been withdrawn with effect from December 15, 2026, the effective date of ISSA 5000” [43].

What replaces it is general rather than specific. ISSA 5000, General Requirements for Sustainability Assurance Engagements, applies “to all assurance engagements on sustainability information … regardless of how that information is presented”, and is effective for periods beginning on or after 15 December 2026 [44]. The FRC issued ISSA (UK) 5000 in November 2025 with the same effective date [45].

12 November 2024
IAASB issues ISSA 5000
A general sustainability assurance standard, replacing the need to apply ISAE 3000 (Revised) for these engagements.
SOURCE: IAASB publication page [44]
17 September 2025
DBT’s assurance consultation closes
It proposed “a voluntary oversight regime and register for entities that offer third-party assurance services for sustainability-related disclosures”.
SOURCE: GOV.UK consultation page [47]
November 2025
FRC issues ISSA (UK) 5000
The UK version, same scope and same effective date. Described by the FRC as being for “voluntary use in sustainability assurance engagements”.
SOURCE: FRC, 12 November 2025 [45][46]
30 January 2026
Government response: the FRC will run it, and by mid-2026
99 responses. The regime is voluntary and opt-in, and because the Audit Reform Bill is not proceeding, “the FRC has been tasked to move forward to establish an interim, non-legislative regime by mid-2026”. Registered practitioners would be required to use ISSA (UK) 5000.
SOURCE: DBT government response, paras 1.9, 1.12–1.13, 4.4 [47]
Today · 19 Aug 2026
15 December 2026
ISAE 3410 withdrawn; ISSA 5000 and ISSA (UK) 5000 take effect
The dedicated GHG assurance standard ceases to exist on the day the general sustainability assurance standard begins.
SOURCE: IAASB [43]; ISSA 5000 para 15 [44]; ISSA (UK) 5000 [45]

ISO 14064 is additional, not alternative

Two ISO standards come up in vendor material, and the relationship between them and the GHG Protocol is routinely misdescribed. ISO 14064-1:2018 is the preparer’s specification for quantification and reporting at organisation level; ISO 14064-3:2019 is the specification for verification and validation [41] [42]. They are not alternatives to each other, and neither is an alternative to the GHG Protocol. ISO says so itself: “The ISO 14064 series is GHG programme neutral. If a GHG programme is applicable, requirements of that GHG programme are additional to the requirements of the ISO 14064 series.”

What assurance actually demands of software

Strip away the standard-setting and the requirement is unchanged from the Corporate Standard’s transparency principle: a clear audit trail. In practice an assurer will ask to walk a number backwards — from the disclosed figure, to the calculation, to the factor and its version, to the activity data, to the source document, and to whoever entered or changed it and when. A platform that can produce that chain on demand makes assurance a sampling exercise. One that cannot makes it a reconstruction project, and reconstruction is billed by the hour.

13 · The rewrite

The standard is being rewritten, and the timeline has slipped twice

Everything in this chapter is draft. That is the most important thing about it, and it is the part vendor blogs keep dropping.

GHG Protocol is consolidating four workstreams — the Corporate Standard, the Scope 2 Guidance, the Scope 3 Standard and a new Actions and Market Instruments workstream — into a single document, harmonised with ISO 14064-1. The deliverable is named in the Standard Development Plan of 29 July 2026: “GHG Protocol Corporate Standard: Corporate Accounting and Reporting Standard (Version 3.0)”, in two parts [9].

As at 19 August 2026 no revised standard has been published, and no consolidated draft has been published for consultation. The 2004 Corporate Standard as amended, the 2015 Scope 2 Guidance and the 2011 Scope 3 Standard remain the standards in force.

The dates, and how they have moved

Stated onConsultationFinal publication
14 October 2025 — Scope 2 blog [15] Revised Scope 2 Standard “anticipated late 2027”
December 2025 — Corporate Standard Phase 1 update [12] “mid-2026” “end-2027”
29 July 2026 — SDP, announcement and FAQ [9][10][11] “estimated Q2 2027” “estimated Q4 2028”
SOURCE: as cited. The SDP itself carries the caveat “The workplan and timeline are subject to change during the standard revision process” [9].

Two consultations have already run. The Scope 2 Guidance and Electricity Sector Consequential Accounting consultation opened on 20 October 2025 and, after an extension “in response to stakeholder feedback”, closed on 31 January 2026 [16]. The Actions and Market Instruments Phase 1 white paper ran a 60-day request for information from 31 March to 31 May 2026 [14]. GHG Protocol’s summary of the Scope 2 outcome runs to a single sentence — that it “highlighted a range of stakeholder perspectives” — so whether hourly matching survived consultation in its proposed form is, on the published record, unresolved.

What is proposed — every item below is draft

01
Scope 2: hourly matching and deliverability — DRAFT Certificates would have to be matched to consumption hourly, and sourced from deliverable grid regions, replacing the 2015 approach of same-year certificates from broad market boundaries. It would apply “only to certificate-backed market-based method claims, not to totals reported using residual mix or other default factors”. Proposed 14 Oct 2025. Implementation “expected to phase in over multiple years”; no effective date has been set [15]
02
Consolidation: equity share eliminated — DRAFT The December 2025 progress update proposes removing the equity share approach entirely, with financial control as the primary basis tied to financial-statement consolidation on a GAAP-agnostic footing. Proposed Dec 2025. “Subject to change and should not be construed as final nor relied upon as advice” [12]
03
Scope 3 becomes mandatory; 1% exclusion caps — DRAFT The same update proposes making Scope 3 reporting mandatory and capping Scope 1 and Scope 2 exclusions at 1% each. Proposed Dec 2025, same disclaimer [12]
04
A 95% Scope 3 inclusion rule — DRAFT “Companies shall account for and report at least 95% of total required scope 3 emissions.” Proposed 31 Mar 2026. “This is not a GHG Protocol Standard; all content is draft and subject to change” [13]
05
A new Category 16; Category 15 narrowed — DRAFT Category 16 would cover facilitated and other value-chain activities, with Category 15 narrowed to investments only — moving insurance and other financial services out of 15. Proposed 31 Mar 2026, same disclaimer [13]
06
A multi-statement structure — DRAFT Four statements rather than one: a physical GHG inventory, a market-based inventory, a GHG impact statement covering consequential and avoided emissions, and non-GHG indicators, with “separate reporting of physical inventory emissions from project-based GHG reductions and trades of market instruments”. Proposed Mar 2026. “Works in progress … should not be construed as final standard text” [14]
The procurement question this raises, and it is not “is the vendor ready for v3.0”

Nobody is ready for a standard that does not exist, and a vendor claiming otherwise is selling a draft as a rule. The useful question is narrower and answerable today: could this platform re-run a closed year on a different set of rules? Hourly matching, if it lands, is a data-architecture change — half-hourly consumption joined to certificate issue and retirement timestamps, by grid region. A tool that already stores consumption at interval resolution and certificates as retired instruments with identifiers has a migration. A tool that stores monthly kWh and a renewable percentage has a rebuild.

14 · The demo

Nine questions for the demo, and the answer that passes

Each one traces to a paragraph of a published document. None of them can be answered with a dashboard.

Vendor demos are optimised. They show you the chart at the end, on data that was prepared for the purpose. These nine questions are designed to be asked in the demo, on the vendor’s own sample data, and to have answers you can see on a screen rather than answers you have to take on trust.

01
“Show me a figure from two years ago, and the factor version that produced it.” You are looking for a field on the record, not a settings page. UK conversion factors are republished annually and the 2026 edition changed the electricity factor’s definitional basis as well as its value. Passes if: the factor table, edition and basis are attributes of the stored figure · DESNZ 2026 factors and methodology report [18][19]
02
“Recompute 2024 on 2026 factors, without changing what 2024 published.” Restatement and the published record are different objects. A tool that overwrites history when factors change has destroyed the comparison the base year exists to support. Passes if: both versions coexist, each labelled · Corporate Standard Chapter 5 and Chapter 9 [2][7]
03
“Show me both Scope 2 numbers, labelled by method.” The Guidance requires two results, each labelled, wherever contractual instruments exist in the market — and exactly one where they do not. Passes if: location-based and market-based are separate, labelled outputs · Scope 2 Guidance § 1.5.1 [4]
04
“What does it print when no residual mix is available?” In the UK that is the normal case, not an edge case. Quality criterion 8 requires the absence to be disclosed. Silently substituting a grid average is an accounting choice made on your behalf, with no record. Passes if: a disclosure is generated, not a substitution · Scope 2 Guidance quality criterion 8 [4][17]
05
“Split Scope 1 and Scope 2 between the consolidated group and other investees.” This is UK SRS S2 paragraph 29(a)(iv), and it is an accounting-boundary question. If the answer involves exporting to a spreadsheet and tagging rows, the platform has a site list rather than an entity model. Passes if: it is a report, not an export · UK SRS S2 para 29(a)(iv) [32]
06
“Show me Scope 3 by category, with the excluded categories and the justification.” The 2011 standard requires accounting for all Scope 3 and disclosing and justifying any exclusions; UK SRS S2 requires the included categories to be named. A single Scope 3 total satisfies neither. Passes if: exclusions are first-class records with justification text · Scope 3 Standard Table 3.1 [5]; UK SRS S2 para 29(a)(vi)(1) [32]
07
“Show gross Scope 1 and Scope 2, independent of any offsets or allowances.” Chapter 9 requires exactly that, verbatim: totals “independent of any GHG trades such as sales, purchases, transfers, or banking of allowances”. Offsets belong in a separate ledger and appear in Chapter 9’s optional information. Passes if: gross and net are separate, and gross is the default · Corporate Standard Chapter 9 [2]
08
“Where do I set my base-year significance threshold, and what happens when a change crosses it?” There is no GHG Protocol threshold to default to. If the tool ships a hard-coded 5%, it is implementing a rule that does not exist; if it has no field at all, it cannot support the policy Chapter 9 requires you to disclose. Passes if: the threshold is your input, and crossing it raises a recalculation task · GHG Protocol 2019 Guidance [7]; Chapter 9 [2]
09
“Show biogenic CO₂ reported separately from the scopes.” A required Chapter 9 element and a good five-second test of whether a platform implements the standard or a summary of it. Biomass and biofuel combustion CO₂ sits outside the scope totals. Passes if: there is a biogenic line, outside Scope 1 · Corporate Standard Chapter 9 [2]

A tenth question is worth asking of the people rather than the product: who signs the methodology statement? SECR paragraph 20F requires the directors’ report to state the methodologies used. That is a statement by directors, informed by a tool. No platform can make it for them, and any vendor implying otherwise is selling something it cannot deliver.

15 · The field

The platforms, and what this page does not claim about them

Seventeen platforms reviewed on the sibling page. Listed here for orientation, grouped by what they are, not ranked.

This page is about mechanics, so it does not rank vendors and it does not assert that any named platform passes the nine questions above — that is what the demo is for, and the answers change with releases. What follows is the roster from the carbon reporting software comparison, where each platform has a fuller write-up, grouped by the kind of product it is.

UK-first platforms
Climatise (London) · Emitwise (London) · Seedling (London). Built around SECR and UK reporting rather than adapted from a global ESG suite. The group where statutory UK output tends to be native rather than configured.
Enterprise carbon platforms
Normative (Stockholm / London) · Greenly (Paris / UK) · Watershed (US / London) · Persefoni (US / UK) · Sweep (Paris / London) · Plan A (Berlin). Broad multi-framework coverage; the group most likely to be handling CSRD and UK reporting together.
Platform-stack modules
Microsoft Sustainability Manager · Salesforce Net Zero Cloud · Workiva Carbon. Bought because the rest of the stack is already there. The integration argument is real; so is the question of whether the emissions model is as deep as a specialist’s.
Industrial and EHS suites
Sphera · IBM Envizi ESG Suite · Cority · SINAI Technologies. Strongest where emissions sit alongside environment, health and safety data, product-level footprints or capital decisions.
Software plus advisory
Sami (Paris, SGS group). Sold with consulting attached, which is a different procurement and a different failure mode — the methodology lives partly with the adviser.
What the groups do not tell you
None of these categories predicts how a platform answers the nine questions. Factor versioning and restatement in particular cut across the groups: they are data-model decisions taken early in a product’s life, and they are invisible in a feature list.
What this site does and does not say about vendors

This page makes no certification, endorsement, award or client claim about any platform listed, and none of the groupings above is a ranking. Where the sibling page marks a capability as native or configured, that is its editorial reading of published vendor material at the time it was written, not a test result. Ask the nine questions yourself. A vendor that cannot show you factor versioning on a stored figure has told you something no comparison table can.

GHG reporting software — wind turbines at dawn over UK farmland, the bottom line on what a platform must actually hold

A greenhouse gas figure is a claim about a boundary, a factor version and a method, expressed as a number. Software that stores only the number cannot restate a base year, cannot tell a definitional change from a decarbonisation trend, and cannot walk an assurer backwards from the disclosure to the source document. Everything else is presentation.

The bottom line · Photo: Unsplash / Zac Wolff
The standard is from 2004
Amended in 2013 for NF₃ and in 2015 for Scope 2. UK SRS S2 names it by title and year at paragraph 29(a)(ii). A consolidated Version 3.0 is in draft, with consultation estimated Q2 2027 and publication estimated Q4 2028.
Scope 3 is called optional in that text
It became required through the separate 2011 Scope 3 Standard, and is proposed to become mandatory in the consolidated standard. Three documents and a draft, not one rule.
Scope 2 is two numbers, or one, never an unlabelled one
Two where contractual instruments exist in the market, one — location-based — where they do not. UK SRS S2 paragraph 29(a)(v) makes the location-based figure the required one.
There is no 5% recalculation rule
GHG Protocol “does not have a set definition for ‘significant’”. You set a threshold, you disclose it, and Chapter 9 requires the policy to be reported.
Factors are versioned data, and 2026 proved it
UK electricity fell 26%, of which six or seven points were methodological and three were a year of data arriving early. The 2025 and 2026 tables are on different bases.
The assurance standard changes on 15 December 2026
ISAE 3410 is withdrawn that day; ISSA 5000 and ISSA (UK) 5000 take effect. The FRC’s voluntary register of assurance providers was promised by mid-2026 and had not launched as at 19 August 2026.
GHG reporting software next steps — climate demonstrators with a There Is No Planet B placard

You now know what the standards require of a platform. The question that decides your shortlist is the one this page cannot answer: which regime actually reaches you, and when.

See which UK regime reaches you Or compare the seventeen platforms in full
GHG reporting software in reference form — a walker standing open-armed in an open field, the sourced record Photo: Unsplash / Quokkabottles
The sourced record

GHG reporting software in reference form

The same material restated for lookup rather than reading — key facts, what is settled and what is not, then the FAQs, the glossary and every source.

Key facts

GHG reporting software — the short version

Every figure below appears earlier on this page with its source. Nothing is introduced here for the first time.

FactPosition as at 19 August 2026
The standard UK SRS S2 names GHG Protocol Corporate Accounting and Reporting Standard, Revised Edition, 2004 — at paragraph 29(a)(ii)
Amendments to it Two — February 2013 (NF₃ added) and January 2015 (Scope 2 Guidance)
Gases Six in the 2004 text; seven since the 2013 amendment
Scope 3 in the 2004 text Described as “an optional reporting category”. Required for conformance with the separate 2011 Scope 3 Standard
Scope 3 categories 15 — 8 upstream, 7 downstream, each with a minimum boundary in Table 5.4
Scope 2 results to report Two where contractual instruments exist in the market; one, location-based, where they do not
Scope 2 quality criteria Eight. Criterion 8 requires a residual mix, or a disclosure of its absence
Official UK residual mix None. AIB publishes a GB figure (280.64 gCO₂/kWh, 2025 vintage) that no UK authority adopts
GHG Protocol base-year significance threshold None. No set definition of “significant”; the company sets and discloses its own
GWP requirement 100-year values, one IPCC assessment report per inventory. AR6 recommended, not required
UK conversion factors, current edition 2026 — DESNZ, published 11 June 2026, last updated 31 July 2026. On AR5
UK electricity factor change, 2025 to 2026 −26%, of which 6–7 percentage points are methodological and 3 are an extra year of data
SECR thresholds 2 of 3 — turnover £36m, balance sheet total £18m, 250 employees. Unchanged by the 2025 Companies Act uplift
Companies Act medium-sized thresholds from 6 April 2025 £54m turnover, £27m balance sheet total, 250 employees — a different test in a different instrument
SECR statutory guidance Last updated 29 March 2019
UK entities required to report under UK SRS None. Published 25 February 2026 for voluntary use, no effective date
UK SRS S2 Scope 3 relief, paragraph C4 Time limit removed; availability deferred to legislation that does not exist
ESOS and GHG reporting ESOS is an energy audit regime. No greenhouse gas reporting requirement. Phase 4 deadline 5 December 2027
ISAE 3410 Withdrawn with effect from 15 December 2026
ISSA 5000 / ISSA (UK) 5000 Effective for periods beginning on or after 15 December 2026
FRC voluntary assurance-provider register Not launched as at 19 August 2026. Promised by mid-2026
Consolidated GHG Protocol Standard v3.0 Not published. Consultation “estimated Q2 2027”, publication “estimated Q4 2028”
SOURCE: as cited throughout this page — GHG Protocol [1][2][3][4][5][6][7][8][9][11][12][13], DESNZ [18][19][20][21], legislation.gov.uk [22][24][25][26][28], GOV.UK [30][31][34][35][38], FCA [36], IAASB and FRC [43][44][45][47][48], AIB [49].
Settled and unsettled

What is decided, and what is genuinely open

The distinction most pages on this subject collapse. Everything in the right-hand column is dated and checkable.

Decided The GHG Protocol Corporate Standard (2004, as amended) is the measurement standard UK SRS S2 names · Scope 2 dual reporting has been required since 2015 · the 15 Scope 3 categories and their minimum boundaries have been fixed since 2011 · SECR is in force and its thresholds did not move in 2025 · ISAE 3410 is withdrawn on 15 December 2026 and ISSA 5000 takes effect that day · the 2026 UK conversion factors are published and on AR5.
Open Whether any UK entity is ever required to apply UK SRS, and when · whether the FCA makes the CP26/5 rules, and on what timetable — no policy statement as at 19 August 2026 · when the UK SRS S2 Scope 3 relief ends, since the legislation that would specify it does not exist · whether hourly matching survives consultation, and from when · what the consolidated Version 3.0 actually says · when the FRC’s assurance register opens.

Two of those open items are worth restating as dated negatives rather than as uncertainty, because the difference matters when a vendor quotes a deadline at you.

A
No FCA policy statement responding to CP26/5 The consultation closed on 20 March 2026. Both the CP26/5 page and the FCA’s sustainability reporting requirements page were last modified on 5 June 2026 and still read that the FCA will “aim to publish a Policy Statement in autumn 2026, subject to the final UK SRS, with the rules coming into force from 1 January 2027”. Checked 19 August 2026 [36][37]
B
No FRC register of sustainability assurance providers The government response of 30 January 2026 tasked the FRC with establishing an interim regime and register “by mid-2026”. The FRC news index carries no launch announcement, opening date or application process, and the FRC’s sustainability assurance library path returns HTTP 404. Checked 19 August 2026 — roughly seven weeks past target [47][48]
Questions

GHG reporting software FAQs

The questions people actually search on this subject, answered from the primary documents rather than from each other.

What is GHG reporting software?

GHG reporting software is a platform that collects activity data, applies emission factors to it, and produces a greenhouse gas disclosure that conforms to a named standard. The standard that matters in the UK is the GHG Protocol Corporate Accounting and Reporting Standard (2004), which UK SRS S2 names by title and year at paragraph 29(a)(ii). The useful test of such a platform is not whether it calculates emissions — anything can — but whether it stores the factor version, the organisational boundary and the base-year recalculation policy alongside the figure, because Chapter 9 of that standard requires all three to be reported.

What is the difference between GHG reporting software and carbon accounting software?

In practice, nothing — the terms are used interchangeably by vendors, and the same products appear under both labels. GHG accounting software and carbon accounting software both usually mean a tool implementing the GHG Protocol. If there is a distinction worth drawing, it is that “carbon” sometimes implies CO₂ alone while a GHG inventory covers seven gases, and that “reporting” emphasises the disclosure output while “accounting” emphasises the measurement. Do not choose a product on the label.

Is GHG reporting mandatory in the UK?

Partly. SECR is mandatory and in force — quoted companies, and large unquoted companies and LLPs meeting the 2-of-3 test, must disclose Scope 1 and Scope 2 emissions, energy use in kWh, at least one intensity ratio, a methodology statement and comparatives, in the directors’ report. UK SRS is not mandatory: S1 and S2 were published on 25 February 2026 for voluntary use, they contain no effective date, and as at 19 August 2026 no legislation requires any entity to apply them. ESOS is mandatory but is not a GHG reporting regime — it requires energy audits, not emissions disclosure.

What is the SECR reporting threshold?

For large unquoted companies and LLPs it is a 2-of-3 test: turnover of more than £36 million, a balance sheet total of more than £18 million, and more than 250 employees. Schedule 7 paragraph 20B of SI 2008/410 frames it as an exemption, so a company is out of SECR if it meets two or more of the limits and in if it exceeds two or more. Quoted companies are in scope regardless of size. Note that the Companies Act medium-sized thresholds rose to £54 million and £27 million on 6 April 2025 — SECR’s figures did not move, because paragraph 20B carries its own table.

Does the GHG Protocol require Scope 3 reporting?

Not in the 2004 Corporate Standard, which describes Scope 3 as “an optional reporting category that allows for the treatment of all other indirect emissions”. Scope 3 accounting is required for conformance with the separate Corporate Value Chain (Scope 3) Standard of 2011, which says companies “shall account for all scope 3 emissions and disclose and justify any exclusions”. Making Scope 3 mandatory in the consolidated Corporate Standard is a draft proposal in a December 2025 progress update, not a rule. Three documents and a draft — not one requirement.

Why does Scope 2 have two numbers?

Because the GHG Protocol Scope 2 Guidance of January 2015 requires it. Companies with operations in markets that provide product or supplier-specific data in the form of contractual instruments “shall report scope 2 emissions in two ways and label each result according to the method” — one location-based, using grid-average factors, and one market-based, using contractual instruments. The Guidance is equally explicit the other way: where no such instruments exist in the market, “only one scope 2 result shall be reported, based on the location-based method”.

Which Scope 2 number does UK SRS S2 require?

Location-based. Paragraph 29(a)(v) requires an entity to “disclose its location-based Scope 2 greenhouse gas emissions, and provide information about any contractual instruments that is necessary to inform users’ understanding”. The market-based figure and the contractual-instrument narrative are supplementary information, not a substitute. A platform that reports only a market-based number does not satisfy 29(a)(v).

Is there a UK residual mix factor?

No official one. The Association of Issuing Bodies publishes a Great Britain residual mix — 280.64 gCO₂/kWh for the 2025 vintage, published 26 May 2026 — and it is the de facto convention because it is the only published GB figure. But the AIB states that “the official residual mixes for each country are in principle published by the respective national authorities”, and no UK authority adopts it. Ofgem operates fuel mix disclosure, which is a different instrument, and the DESNZ conversion factors contain no residual mix at all. Scope 2 quality criterion 8 provides for exactly this case: the residual mix must be made available, “or its absence shall be disclosed by the reporting entity”.

What are the 15 Scope 3 categories?

Upstream: 1 purchased goods and services; 2 capital goods; 3 fuel- and energy-related activities (not included in scope 1 or scope 2); 4 upstream transportation and distribution; 5 waste generated in operations; 6 business travel; 7 employee commuting; 8 upstream leased assets. Downstream: 9 downstream transportation and distribution; 10 processing of sold products; 11 use of sold products; 12 end-of-life treatment of sold products; 13 downstream leased assets; 14 franchises; 15 investments. Each has a minimum boundary defined in Table 5.4 of the 2011 standard, and category 3’s parenthetical is part of its official name — it is what stops it double-counting Scopes 1 and 2.

Is supplier-specific Scope 3 data more accurate than spend-based data?

Not necessarily, and the GHG Protocol says so. The Scope 3 Technical Guidance states at Box 1.1 that although supplier-specific and hybrid methods are “more specific to the individual supplier”, “they may not produce results that are a more accurate reflection of the product’s contribution to the reporting company’s scope 3 emissions”, and that supplier data “may actually be less accurate than industry-average data” because of allocation complexity and reliability. The Guidance’s own ranking of data levels is explicitly a ranking of specificity, not of quality. Specificity is worth pursuing; it is not the same thing as accuracy.

What is the GHG Protocol’s 5% rule for base-year recalculation?

There isn’t one. GHG Protocol’s own 2019 Scope 1 & 2 Inventory Guidance states that the Corporate Standard “does not have a set definition for ‘significant’, however a company should determine its own significance threshold (i.e. 2 percent)” — and that 2% is a worked example, introduced with “i.e.”, not a rule. The company sets its own threshold and discloses it. Chapter 9 of the Corporate Standard lists the base-year recalculation policy among the information a public GHG report must contain. Software that ships a hard-coded 5% threshold is implementing a rule that does not exist.

When do you have to recalculate your base year?

The 2019 Guidance names three triggers: “significant changes in the structure of the reporting company”; “significant changes in the calculation methodology”; and “discovery of significant errors or smaller errors that are collectively significant”. The distinction that decides most real cases is structural versus organic. Acquisitions, divestitures, outsourcing, insourcing, boundary changes and method changes are structural and trigger recalculation. Opening a facility you built, growing, shrinking or genuinely reducing emissions are organic — recalculating those away would destroy the comparison the base year exists to make.

Which emission factors should a UK company use?

The UK government’s own. The current edition is Greenhouse gas reporting: conversion factors 2026, published by DESNZ on 11 June 2026 and last updated 31 July 2026. Its stated scope is that it “enable[s] users to calculate and report greenhouse gas emissions from their UK activities in 2026”, suitable for UK-based organisations of all sizes and for international organisations reporting on their UK operations. It is updated annually, with a methodology report and a major changes report alongside — and the publication month moves, so do not build a process that assumes a June refresh.

Why did the UK electricity emission factor drop so much in 2026?

UK electricity fell 26% between the 2025 and 2026 editions, and most of that is not decarbonisation. DESNZ’s major changes report explains that the data lag was reduced from two years to one, so the change “reflects two years’ worth of changes in the electricity grid mix and grid losses, rather than the usual one year”. Of the fall, grid mix changes from 2023–2024 accounted for 16 percentage points, the extra year of data for 3, and “the remaining 6-7pp of the decrease is due to methodological changes, improvements and corrections” — including improved import and export accounting and a double-counting fix affecting autogenerators. The 2025 table also excluded imported electricity where the 2026 table includes it, so the two are not like-for-like.

Which IPCC GWP values should I use — AR5 or AR6?

GHG Protocol requires 100-year GWP values from the IPCC and requires you to use values from a single assessment report for any one inventory. It does not name a report. Its Global Warming Potential Values document of 7 August 2024 recommends AR6 while acknowledging that AR4 and AR5 values are still used. The UK government’s 2026 conversion factors use AR5 — methane at 28 and nitrous oxide at 265, the 100-year values excluding climate–carbon feedbacks. So a UK reporter using DESNZ factors is on AR5 while the Protocol recommends AR6. That is permitted, not a defect, but it is a divergence your software has to handle explicitly, because base year and current year must use the same values.

Does SECR require Scope 3 reporting?

Essentially no. The government’s Environmental Reporting Guidelines state: “You are not required to report on other emissions associated with inputs into your company (such as emissions from your supply chain)”. There is exactly one Scope 3 element inside the mandatory calculation for large unquoted companies — fuel used in personal or hire cars on business use, including fuel reimbursed on business mileage claims. Taxi journeys where you do not operate the firm are outside it. Anything wider is voluntary.

What must a SECR disclosure actually contain?

For large unquoted companies, Schedule 7 Part 7A requires: emissions in tonnes CO₂e from gas combustion and transport fuel (20D(1)); emissions from purchased electricity (20D(2)); aggregate energy consumed in kWh (20D(3)); a description of the principal energy efficiency measures taken, if any (20D(4)); the methodologies used (20F); at least one intensity ratio (20G); and the prior year’s figures as comparatives, except in the first year (20H). Quoted companies have parallel requirements at paragraphs 15–18A on a global basis, stating the UK and offshore proportion separately.

What is the 40,000 kWh SECR exemption?

Where a company consumed 40,000 kWh of energy or less in the United Kingdom during the reporting period, the report need not contain the energy and emissions information. But it is an exemption from disclosure, not from the regime: the report must state that the company is not disclosing, and why. A platform whose SECR output simply produces nothing for a low-energy user has produced a non-compliant report, because that statement is itself required.

Can you claim compliance with UK SRS S2 without reporting Scope 3?

As the standards stand, yes. UK SRS S2 paragraph C4 permits an entity not to disclose Scope 3 information, and the UK removed the “first annual reporting period” limit that IFRS S2 places on that relief — the government response records that its availability “will, instead, be specified in legislation or regulation”, and no such legislation exists as at 19 August 2026. UK SRS S1 paragraph 73A confirms that an entity using C3 or C4 “is not prevented from asserting compliance with UK SRS S2”, provided it discloses the use. The asymmetry is that the climate-only relief at S1 paragraph E3 does cost the entity its S1 compliance statement.

Does UK SRS S2 require PCAF for financed emissions?

No. A full-document search of the published UK SRS S2 for “PCAF” and “Partnership for Carbon Accounting Financials” returns nothing. What paragraphs B58–B63A require is disclosure about methodology — for asset management, “the methodology used to calculate the financed emissions, including the method of allocation the entity used to attribute its share of emissions in relation to the size of investments”, with commercial banking and insurance mirroring that against gross exposure. PCAF is the market convention and most firms use it, but it is an implementation choice, not a requirement of the standard.

Does ESOS require greenhouse gas reporting?

No. ESOS is an energy audit regime. It requires an organisation to measure total energy consumption, identify areas of significant consumption covering at least 95% of the total, calculate energy intensity ratios, carry out audits or use a deemed-compliance route such as ISO 50001, produce a report with director-level sign-off, notify compliance and file an action plan. There is no greenhouse gas emissions reporting requirement in it. The Environment Agency’s guidance draws the link only in the other direction — ESOS energy data can help meet SECR requirements. The Phase 4 compliance notification deadline is 5 December 2027, with a qualification date of 31 December 2026.

Which assurance standard applies to a greenhouse gas statement?

Until 15 December 2026, ISAE 3410, the IAASB’s standard written specifically for assurance engagements on greenhouse gas statements. From that date it is withdrawn — the IAASB states that “ISAE 3410 has been withdrawn with effect from December 15, 2026, the effective date of ISSA 5000”. ISSA 5000 and the FRC’s ISSA (UK) 5000 take effect for periods beginning on or after that date and apply to all assurance engagements on sustainability information. ISO 14064-3:2019 remains available for verification and validation of GHG statements; note that ISO describes the 14064 series as GHG programme neutral, with a programme’s requirements being “additional to” ISO’s rather than replaced by them.

Is the GHG Protocol being updated?

Yes, and nothing has been published yet. GHG Protocol is consolidating the Corporate Standard, the Scope 2 Guidance, the Scope 3 Standard and a new Actions and Market Instruments workstream into a single “GHG Protocol Corporate Standard … (Version 3.0)”, harmonised with ISO 14064-1. Its 29 July 2026 update gives “a consolidated public consultation in Q2 2027 and publication of the consolidated joint corporate standard in Q4 2028” — estimates that have moved twice in nine months, from “mid-2026 / end-2027” in December 2025. As at 19 August 2026 no consolidated draft has been published for consultation and the existing standards remain in force.

What is hourly matching, and does my software need it?

Hourly matching is a draft proposal for the revised Scope 2 standard: organisations using certificates would have to match them to consumption hourly, and source them from deliverable grid regions, replacing the 2015 approach of same-year certificates from broad market boundaries. It would apply only to certificate-backed market-based claims. It is not required today, no effective date has been set, and GHG Protocol says implementation “is expected to phase in over multiple years” after publication. The sensible procurement question is not whether a platform supports hourly matching but whether it stores consumption at interval resolution and certificates as retired instruments with identifiers — because that is the difference between a migration and a rebuild.

Glossary

The GHG reporting software vocabulary, defined

Eighteen terms that appear on this page and are routinely used loosely elsewhere.

GHG Protocol Corporate StandardThe Greenhouse Gas Protocol: A Corporate Accounting and Reporting Standard, Revised Edition, WRI/WBCSD, March 2004. Amended February 2013 (NF₃) and January 2015 (Scope 2). Named by UK SRS S2 at paragraph 29(a)(ii).
Organisational boundaryWhich operations are inside the inventory. Chapter 3 offers equity share or control; a company choosing control then chooses financial or operational control.
Operational boundaryWhich emissions from those operations are counted, and in which scope. Chapter 4.
Scope 1“Direct GHG emissions occur from sources that are owned or controlled by the company.”
Scope 2Emissions from generating the energy the company purchases. Defined in 2004 for purchased electricity; steam, heat and cooling were folded in by the 2015 Guidance.
Scope 3All other indirect emissions in the value chain. Described as optional in the 2004 text; governed by the separate 2011 Scope 3 Standard, which requires accounting for all of it with exclusions disclosed and justified.
Location-based methodScope 2 calculated on the average emissions intensity of the grids where consumption occurs, using grid-average factors. The method UK SRS S2 paragraph 29(a)(v) requires.
Market-based methodScope 2 calculated from contractual instruments — what the company purposefully bought. Required only where such instruments exist in the market.
Contractual instrumentEnergy attribute certificates (REGOs in the UK, GOs in the EU, RECs in the US), direct contracts, supplier-specific emission rates, and default factors for untracked energy. An attribute claim, not a carbon offset.
Residual mixThe emissions intensity of electricity left over after contractual instruments are claimed. There is no official UK residual mix; criterion 8 requires the absence to be disclosed.
Minimum boundaryThe activities that must be included in each Scope 3 category, fixed by Table 5.4 of the 2011 standard. Going beyond it is optional; falling short is an exclusion that must be justified.
Base yearThe reference year a company’s emissions trend is measured against. Chapter 9 requires it to be stated, together with the recalculation policy and an emissions profile over time.
Significance thresholdThe change, in aggregate, at which a company recalculates its base year. The company sets and discloses it; the GHG Protocol has no set definition of “significant”.
GWPGlobal warming potential — the factor converting a gas into CO₂e. GHG Protocol requires 100-year values from a single IPCC assessment report and recommends AR6. The UK conversion factors use AR5.
Conversion factorThe published coefficient converting an activity figure into emissions. In the UK, published annually by DESNZ; the 2026 edition is current.
Biogenic CO₂Carbon dioxide from burning biomass or biofuels. Chapter 9 requires it to be reported separately from the scopes, not folded into Scope 1.
SECRStreamlined Energy and Carbon Reporting. In force since financial years beginning on or after 1 April 2019. Obligations live in Schedule 7 Parts 7 and 7A of SI 2008/410, not in the 2018 SI that inserted them.
ISSA 5000The IAASB’s general sustainability assurance standard, effective for periods beginning on or after 15 December 2026 — the day ISAE 3410 is withdrawn. The FRC’s UK version is ISSA (UK) 5000.
Primary sources

GHG reporting software — every source, linked

Primary documents only. Where a quotation reached this page through a secondary reproduction rather than the original PDF, the citation on the relevant section says so.

  1. The Greenhouse Gas Protocol: A Corporate Accounting and Reporting Standard (Revised Edition) — WRI and WBCSD, March 2004
  2. Chapter 9 — Reporting GHG Emissions — the required and optional reporting elements of the above, WRI chapter text
  3. Required Greenhouse Gases in Inventories: Accounting and Reporting Standard Amendment — GHG Protocol, February 2013. Adds NF₃; sets the 100-year single-assessment-report GWP rule
  4. GHG Protocol Scope 2 Guidance — WRI and WBCSD, January 2015. An amendment to the Corporate Standard; dual reporting and the eight quality criteria
  5. Corporate Value Chain (Scope 3) Accounting and Reporting Standard — WRI and WBCSD, September 2011. The 15 categories and Table 5.4 minimum boundaries
  6. Technical Guidance for Calculating Scope 3 Emissions, version 1.0 — WRI and WBCSD, 2013. Box 1.1 on specificity and accuracy
  7. Scope 1 & 2 GHG Inventory Guidance — GHG Protocol, November 2019. The recalculation triggers, and the absence of a set definition of “significant”
  8. Global Warming Potential Values, version 2.0 — GHG Protocol, 7 August 2024. AR4, AR5 and AR6 tabulated; AR6 recommended
  9. Consolidated Corporate Standard — Standard Development Plan — GHG Protocol, 29 July 2026
  10. GHG Protocol announces key standard development updates — GHG Protocol, 29 July 2026
  11. Standard development updates — FAQ resource — GHG Protocol, 29 July 2026. Consultation “estimated Q2 2027”; publication “estimated Q4 2028”
  12. Corporate Standard Phase 1 Progress Update — GHG Protocol, December 2025. Draft: equity share removed, Scope 3 mandatory, 1% exclusion caps
  13. Scope 3 Phase 1 Progress Update — GHG Protocol, 31 March 2026. Draft: 95% inclusion rule, new Category 16
  14. Actions and Market Instruments Phase 1 White Paper and RFI — GHG Protocol, March 2026. Draft: the multi-statement structure
  15. Upcoming Scope 2 public consultation: hourly matching and deliverability — GHG Protocol, 14 October 2025
  16. GHG Protocol opens public consultations on Scope 2 and Electricity Sector Consequential Accounting — 20 October 2025; extended to 31 January 2026
  17. Instructions for Proposing Revisions to the Scope 2 Standard — GHG Protocol, 16 December 2024. Reproduces the eight quality criteria
  18. Greenhouse gas reporting: conversion factors 2026 — DESNZ, published 11 June 2026, last updated 31 July 2026
  19. 2026 GHG conversion factors: methodology report — DESNZ, 152 pages. Table 9 and the AR5 basis
  20. Conversion factors 2026: major changes — DESNZ, 18 pages. Entry 17 explains the −26% electricity change
  21. Government conversion factors for company reporting — DESNZ collection page; every edition and its publication date
  22. The Companies (Directors’ Report) and Limited Liability Partnerships (Energy and Carbon Report) Regulations 2018 — SI 2018/1155. The amending instrument that inserted SECR
  23. SI 2008/410, Schedule 7 Part 7 — SECR requirements for quoted companies
  24. SI 2008/410, Schedule 7 Part 7A — SECR requirements for unquoted companies and LLPs
  25. SI 2008/410, Schedule 7 paragraph 20B — the SECR qualifying conditions: £36m, £18m, 250
  26. SI 2008/410, Schedule 7 paragraph 20D — what must be disclosed, and the 40,000 kWh exemption
  27. SI 2008/410, Schedule 7 paragraphs 20F, 20G and 20H — methodology, intensity ratio and comparatives
  28. The Companies (Accounts and Reports) (Amendment and Transitional Provision) Regulations 2024, regulation 10 — SI 2024/1303, in force 6 April 2025. Medium-sized thresholds to £54m / £27m
  29. Explanatory Memorandum to SI 2024/1303 — DBT. Paragraph 6.7 confirms SECR is unaffected
  30. Environmental reporting guidelines: including Streamlined Energy and Carbon Reporting requirements — Defra / HM Government. Last updated 29 March 2019
  31. UK Sustainability Reporting Standards (UK SRS) S1 and UK SRS S2 — DBT, 25 February 2026
  32. UK SRS S2 Climate-related Disclosures — DBT, 25 February 2026, 45 pages. Paragraph 29(a) and Appendix B
  33. UK SRS S1 General Requirements for Disclosure of Sustainability-related Financial Information — DBT, 25 February 2026, 45 pages. Paragraph 73A
  34. UK Sustainability Reporting Standards — GOV.UK guidance, last updated 25 February 2026. “Available for voluntary use”
  35. Government response to the consultation on UK Sustainability Reporting Standards — DBT, 25 February 2026. Annex A on the C3 and C4 reliefs
  36. CP26/5: Aligning listed issuers’ sustainability disclosures with international standards — FCA. Closed 20 March 2026; page last updated 5 June 2026
  37. Sustainability reporting requirements — FCA, last updated 5 June 2026
  38. How to comply with the Energy Savings Opportunity Scheme phase 4 — Environment Agency, published 30 July 2026, last updated 3 August 2026
  39. Energy Savings Opportunity Scheme (ESOS) — GOV.UK guidance, last updated 16 February 2026
  40. The Energy Savings Opportunity Scheme (Amendment) Regulations 2026 — SI 2026/701, in force 22 July 2026
  41. ISO 14064-1:2018 — organisation-level GHG quantification and reporting
  42. ISO 14064-3:2019 — verification and validation of GHG statements
  43. Assurance on a Greenhouse Gas Statement (ISAE 3410) — IAASB. “Withdrawn with effect from December 15, 2026”
  44. ISSA 5000, General Requirements for Sustainability Assurance Engagements — IAASB. Effective for periods beginning on or after 15 December 2026
  45. ISSA (UK) 5000 — Financial Reporting Council, November 2025
  46. FRC takes steps to support quality and consistency in the assurance of sustainability reporting — FRC, 12 November 2025
  47. Assurance of sustainability reporting — DBT consultation, 25 June to 17 September 2025, and the government response of 30 January 2026
  48. FRC sets out year of delivery in Plan and Budget for 2026/27 — FRC, 27 March 2026
  49. European Residual Mixes 2025, version 1.0 — Association of Issuing Bodies, 26 May 2026. The Great Britain figure and its untracked share
  50. Fuel Mix Disclosure (FMD) — Ofgem
  51. Fuel mix disclosure data table 2025 — DESNZ. The residual fuel mix, as percentages only
  52. The Global GHG Accounting and Reporting Standard Part A: Financed Emissions, third edition — PCAF, December 2025
  53. Directive (EU) 2026/470 — EUR-Lex. Adopted 24 February 2026, in force 18 March 2026. The Omnibus I scope narrowing
  54. Council signs off simplification of sustainability reporting and due diligence requirements — Council of the EU, 24 February 2026
  55. Renewable Energy Guarantees of Origin (REGO) — Ofgem. The UK energy attribute certificate
Keep reading

Where to go next

This page covers the mechanics a platform must implement. These cover the regimes, the standards and the products themselves.

The seventeen platforms in full, with budgets, implementation time and a matcher.
The framework itself, explained rather than applied to procurement.
The three scopes defined, with worked UK examples.
All fifteen categories, in detail, with the minimum boundaries.
Who is in scope, what must be disclosed, and where it goes.
Measuring emissions from first principles, for a UK organisation.
The climate standard in full, beyond its greenhouse gas paragraphs.
The wider ESG reporting tools, where carbon is one module of several.
What assurance involves, and what changes on 15 December 2026.
Before you go

You now know what the standards require of GHG reporting software. The remaining question is which UK regime actually reaches you, and on what timetable.

See which regime reaches you

Photography: Unsplash (free licence) — Ricardo Gomez Angel, Paula Prekopova, Alexander Abero, Zbynek Burival, Nikola Jovanović, Nick Fewings, @name_ gravity, Nicholas Doherty, Noah Buscher, Zac Wolff, Li-An Lim, Quokkabottles.

A reference on GHG reporting software and the standards it implements. Every figure cited to a named, dated primary source. Nothing here is advice. Privacy · Terms Spotted an error? hello@uksrs.org.uk
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