Hourly Matching for Scope 2? What 1,100 Consultation Responses Told the GHG Protocol

Hourly matching would require every renewable certificate behind a market based Scope 2 figure to be issued and redeemed for the same hour as the electricity it covers. This paper answers one question. What did the GHG Protocol consultation actually say about it and what does that mean for a UK landlord reporting a REGO backed zero? The answer comes from the consultation feedback published on 29 July 2026 and the minutes of the expert group that drafted the proposal. Of the 909 people who rated hourly matching 70% gave it no or low support. The expert working group had backed it 27 votes to 16.

Summary of findings

The findings in six numbers

Source. GHG Protocol consultation feedback [1] and working group minutes [2] and standard development announcement [3].

The result is not close. Table 19 of the summary of feedback records 909 responses to the hourly matching question. The form numbered it question 71. 22% rated it 4 or 5 for support and 7% were neutral and 70% rated it 1 or 2 [1]. The executive summary puts it plainly. The proposals for hourly matching and deliverability showed low levels of support by respondents [4].

Support tracks what the respondent would have to do. Companies gave 12% support and 82% no or low support across 429 responses. Industry groups matched them at 12% and 82% across 76 responses. Data and analytics or software providers gave 81% support across 21 responses [1]. Only four of the fifteen respondent groups gave more support than opposition and together they account for 128 of the 909 responses.

The experts had reached the opposite view. At its sixteenth meeting on 25 June 2025 the Scope 2 Technical Working Group held an indicative vote on the same proposal. Of 43 members voting 21 fully supported it and 6 supported it with concerns or suggestions. That is 27 in favour against 11 with significant concerns and 5 not supporting it [2].

Nothing has been decided. The announcement of 29 July 2026 folds the Scope 2 Guidance together with the Corporate Standard and the Scope 3 Standard into a single corporate standard written jointly with the International Organization for Standardization (ISO) with a consolidated public consultation in Q2 2027 and publication in Q4 2028 [3]. It does not mention hourly matching. Annual retirement of certificates remains permitted under the 2015 criteria until a new standard replaces them [5].

Why hourly matching matters for UK landlords

Most UK landlords buy common parts electricity on a renewable tariff and report a market based Scope 2 at or near zero. British Land states that 93% of its purchased electricity in FY26 was backed by Renewable Energy Guarantees of Origin (REGOs) and that the REGOs are retired annually in June [6]. Its FY26 ran from 1 April 2025 to 31 March 2026 [6]. Annual retirement is exactly the practice hourly matching would end.

The zero is not a rounding. It is the whole figure. Under the 2015 quality criteria a contractual instrument must be issued and redeemed as close as possible to the period of energy consumption to which the instrument is applied [5]. That is criterion 4 of the eight quality criteria. Six of the eight apply to every instrument used in the market based method [5]. In a market where certificates are issued monthly and retired annually that criterion is met by a calendar year. An hourly criterion would test 8760 periods instead of one.

The exposure is asymmetric. UK Sustainability Reporting Standard S2 (UK SRS S2) requires location based Scope 2 and the information about contractual instruments that users need to understand it. It says an entity might disclose the market based figure rather than that it must [7]. The Financial Conduct Authority applies the standard to listed commercial companies on a comply or explain basis for accounting periods beginning on or after 1 January 2027 [8]. A landlord whose market based zero moves will not have breached the required disclosure. It will have to explain why a number it has published for years changed without any change in its buildings or its contracts.

The Science Based Targets initiative requires a single and consistent Scope 2 approach for setting a target and tracking progress against it [9]. A sustainability performance target written on a market based basis inherits whatever the accounting rule becomes.

Definitions

Hourly matching means an energy attribute certificate is issued and redeemed for the same hour as the electricity consumption it is applied to. It is also called temporal matching or temporal correlation. Deliverability means the generation behind the certificate could physically reach the consuming load. Both were put to the same consultation as revisions to quality criteria 4 and 5 [10].

Scope 2 covers indirect emissions from purchased electricity and heat and steam and cooling. A location based figure prices electricity at the average emission factor of the grid. A market based figure prices it by the contracts and certificates held. The GHG Protocol requires companies with operations in markets that offer contractual instruments to report by both methods and calls this dual reporting [11]. A REGO is a certificate for one megawatt hour of renewable output. A residual mix is the emission factor of the electricity left after all claimed certificates are removed. A conversion factor turns a kilowatt hour into a quantity of greenhouse gas and a factor set is a dated collection of those factors published together.

Half hourly data is electricity consumption recorded in half hour intervals and collected automatically from the meter. An MPAN is the Meter Point Administration Number that identifies an electricity supply point in Great Britain. Data coverage is the share of a portfolio with actual data behind its figures.

An audit trail records who changed what and when alongside the data. An evidence pack is the assembled set of source documents supporting a disclosure. Assurance is the independent review that tests them. Operational carbon is the emissions from running a building.

The Independent Standards Board (ISB) oversees GHG Protocol standard development and a Technical Working Group (TWG) supplies the technical content. tCO2e is tonnes of carbon dioxide equivalent and MWh is megawatt hours.

Method

Four primary documents were read in full on 12 October 2026. The consultation proposal of October 2025 [10]. The summary of feedback and its executive summary published on 29 July 2026 [1] [4]. The minutes of Scope 2 Technical Working Group meeting 16 [2]. The standard development announcement of 29 July 2026 [3].

The response figures come from Table 19 of the summary of feedback which reports question 71 by organisation type [1]. The 15 organisation type counts in that table were summed and they total 909 which matches the published grand total. The published support and neutral and low support percentages were then reweighted by those counts as a check. The result is 22.3% and 7.5% and 70.3% against the published 22% and 7% and 70%. The small difference is rounding in the per group percentages.

The working group vote comes from the indicative vote recorded in the meeting 16 minutes [2]. Support is counted as fully support plus support with concerns or suggestions. Opposition is counted as significant concerns plus do not support. The one unsure vote on the deliverability question is reported separately and excluded from both. The minutes record the vote as indicative and state that its purpose was to document consensus and to inform decisions by the Independent Standards Board [2].

The worked example in Finding 5 uses an invented portfolio and is labelled as such. It applies the Great Britain residual mix factor published by British Land and the UK electricity generation factors from the 2026 DESNZ methodology paper [6] [12]. Peer reviewed studies were found through Google Scholar and each was checked at its publisher page or its Digital Object Identifier (DOI) record or an open repository copy.

Findings

Finding 1. Seven in ten respondents gave hourly matching no or low support

The consultation form was open for a 104 day period between 20 October 2025 and 31 January 2026 [10]. It drew nearly 1100 responses from 56 countries [4]. 909 of those rated the hourly matching proposal [1].

Table 1. Ratings for the hourly matching proposal

Source. Table 19 on page 49 of the summary of feedback [1]. Table 20 on page 50 reports the same grand total by geographic region.

Opposition outweighed support by about three to one. The executive summary records that low levels of support were most prevalent among companies and industry groups and in North and South America and in East and South East Asia. GHG reporting programmes and data providers showed higher levels of support [4].

Finding 2. Support tracked the respondent role rather than the argument

The feedback summary breaks the 909 responses into 15 organisation types. The spread between them is wider than the spread between regions.

Table 2. Hourly matching support by organisation type

Source. Table 19 on page 49 of the summary of feedback [1]. Group names are shortened from those printed. Two groups are omitted from this table and are included in the total. Electric grid operators numbered 2 and split 50% either way and international agencies numbered 1. The balance in each row is the neutral rating of 3.

Companies and industry groups are 505 of the 909 responses. Both gave 12% support and 82% no or low support. Only four groups gave more support than opposition. They are academia and research and data and software providers and GHG reporting programmes and non profit organisations. Together they account for 128 responses or 14% of the total.

The two smallest results are the most pointed. Data analytics and software providers would build the hourly accounting systems and they gave the highest support at 81%. The six verification and assurance providers would have to test the result and they gave zero support. Both groups are too small to carry statistical weight and both are recorded here as published.

Finding 3. The expert working group had voted the other way

The proposal did not come from the Secretariat alone. A Technical Working Group drafted it and voted on it before the consultation opened. At meeting 16 on 25 June 2025 the group held an indicative vote intended to document the level of consensus or disagreement across key Phase 1 revisions and to help the Secretariat determine topics that need further discussion prior to public consultation [2].

Table 3. The same two proposals put to the working group and to the public

Source. Working group indicative vote in the meeting 16 minutes [2] and Table 19 of the summary of feedback [1]. Working group support percentages calculated by this paper as fully support plus support with concerns or suggestions over total votes cast.

On hourly matching the working group supported the proposal 1.7 to 1 and the public opposed it 3.2 to 1. The difference between 62.8% and 22% is 41 percentage points on the same question. The experts voted seven months before the consultation closed. 42 working group members were listed as attending that meeting and the vote tables record 43 of 45 members voting on this question [2].

This is the finding that matters for anybody reading the headline. The proposal was not a Secretariat idea that experts rejected. It was an expert recommendation that the market rejected.

Finding 4. The proposal would tighten two criteria that a calendar year currently satisfies

The 2015 Scope 2 Guidance sets eight quality criteria for contractual instruments. Criteria 1 to 5 and criterion 8 apply to every instrument used in the market based method and the other two are conditional [5]. The consultation proposed replacing the wording of two of them.

Table 4. Current and proposed wording of the two criteria

Source. Scope 2 Quality Criteria in Table 1 on page 6 of the 2015 guidance [5] and criterion 4 on page 21 and criterion 5 on page 23 of the consultation proposal [10]. The 2015 table numbers the criteria without naming them. The names in the third column are those proposed in 2025. Wording is reproduced without the punctuation of the originals.

The proposal anticipated that hourly certificates would often not exist. Where hourly contractual instruments are not available it states that production load profiles shall be combined with monthly or annual contractual instruments to estimate hourly data [10]. That is a modelling step. A modelled figure carries a different data coverage position from a metered one.

For a landlord the practical requirement is a consumption profile at hourly resolution per supply point. Half hourly data against each MPAN already exists for most larger meters so the consumption side is largely in place. The certificate side is not. A REGO carries a generation month rather than an hour.

Finding 5. What hourly matching would do to a REGO backed zero

The following is a worked example and not an observed portfolio. A landlord buys 10000 MWh of electricity. All of it is REGO backed and the market based Scope 2 is reported as zero. Under an hourly rule the volume that falls outside a matched hour would be priced at a residual mix rather than at zero. British Land publishes a Great Britain residual mix of 0.42076 kgCO2e per kWh for 2024 sourced from RE DISS European Residual Mixes 2024 version 1.1 of 11 August 2025 [6]. The UK electricity generation factor is 0.17700 in the 2025 factor set and 0.13096 in the 2026 set [12].

Table 5. Worked example. Market based Scope 2 at different unmatched shares

Source. Worked example by this paper. Residual mix factor from British Land reporting criteria [6] and generation factor of 0.17700 from the 2025 set [12]. Location based Scope 2 for 10000 MWh at that factor is 1770.0 tCO2e. The portfolio is invented.

The residual mix is 2.4 times the 2025 generation factor and 3.2 times the 2026 factor because claimed renewable output has been removed from it. Above about 42% unmatched the market based figure would exceed the location based figure for the same electricity. A reader who assumes the market based number can only be lower than the location based number would be wrong under an hourly rule.

This paper found no published figure for the unmatched share of a UK commercial portfolio. The closest measured work is European. Scholta and Blaschke studied 24 European countries trading guarantees of origin and find that green electricity supply consistently meets green electricity demand when accounting on an annual volumetric basis. In 2021 under coverage was 0.7% under quarterly matching and 4.3% under hourly matching [13]. The hourly gap is about six times the quarterly gap on the same data. They also report uncovered intervals peaking at 66.8% in the fifth hour of the day. All four figures come from the results of that paper rather than its abstract.

That last figure cuts both ways for property. An office with a daytime load profile overlaps solar generation and would be matched more easily than a 24 hour asset. Student accommodation and self storage and data centres carry overnight load and would not. The unmatched share is a property level question and no portfolio can assume the European average applies to it.

Finding 6. The research says annual matching does little and hourly does more at a cost

The consultation did not test whether hourly matching works. The modelling literature does.

Table 6. What peer reviewed studies find

Source. Abstracts and open text of the studies cited. The three restrictions tested by Bjørn et al are geographical proximity and facility age and power purchase agreement type. Hourly matching is not one of them. The Riepin and Brown premium is for the Ireland 2025 scenario.

The direction is consistent. Annual matching moves little and hourly matching moves more and it costs more. None of these studies covers UK commercial property and all but one model systems rather than buildings. The Zou study is the only buildings work in the set and it uses United States grid data.

The Bjørn study is the closest evidence that a rule change moves reported figures rather than only methodology. It did not test hourly matching so it should not be read as a forecast of what hourly matching would do.

What this means in practice

The decision is not made and the published timeline is long. The consultation closed on 31 January 2026 and the feedback was published 179 days later. The Scope 2 Guidance has since been folded into a single corporate standard written jointly with ISO alongside the Corporate Standard and the Scope 3 Standard and the Actions and Market Instruments workstream and ISO 14064 part 1 [3].

Table 7. Published dates on the Scope 2 revision

Source. Consultation proposal [10] and standard development announcement [3]. Dates after 29 July 2026 are announced and not legislated or adopted.

The executive summary records that in July the ISB set that direction. Having reviewed the consultation feedback it called for further work on multiple market based method reporting approaches that reflect different theories of change and tasked the TWG with refining the approach and resolving open questions [4]. Multiple approaches is not the same as hourly matching and it is not the same as the status quo. Neither outcome can be assumed.

Five actions before the next reporting cycle

1. Report the market based figure with its retirement basis stated

Say in the basis of reporting that certificates are retired annually and name the month. British Land states that its REGOs are retired annually in June [6]. A reader who knows the basis can judge what an hourly rule would change. A reader who does not will assume the zero is robust to any rule.

2. Measure the unmatched share before a rule requires it

Hourly consumption already exists for most larger supply points. Set it against the generation profile of the contracted sources and calculate the share that would fall outside a matched hour. Finding 5 shows the range. The exercise costs a week and removes the main unknown.

3. Keep the certificate record against the consumption it covers

Hold each certificate batch against the meter and the period rather than as an annual total in a supplier letter. The article on automating utility data collection covers what a repeatable feed needs. An evidence pack assembled per period survives a rule change. An annual summary does not. This is a record keeping step for the landlord rather than something a reporting platform can supply.

4. Do not write a target or a covenant that assumes the rule

A target set on a market based basis inherits the accounting rule [9]. A figure that feeds a sustainability linked loan margin or an internal carbon price should state which basis and which standard version it rests on. The article on setting a science based net zero target covers how baseline years differ across a portfolio.

5. Record the method version that produced each published figure

UK SRS S2 asks an entity to disclose its measurement approach and the inputs and assumptions behind it and the reason for choosing them and any changes made to them during the reporting period [7]. If the rule changes in 2028 the disclosure needed is the difference between the old basis and the new one. That is only possible if the old basis was recorded at the time.

How Sustainify AI supports market based reporting

Carbon data governance pins each factor set to its reporting period and locks a period when it closes so a figure produced under the 2015 criteria stays reproducible under them. Carbon data lineage traces each Scope 2 figure to the entry and the factor behind it. Carbon data integration takes meter and invoice data through a validating importer and keeps the source file against every row it creates.

The platform supports the disclosure. It does not perform hourly matching and it does not hold certificate registers. It does not replace an assurance provider and it does not predict what the revised standard will require.

Disclosure of interest. This paper is published by Sustainify AI. The analysis used the public sources and the method set out in the Method section and was carried out independently of the platform.

Limitations

A consultation is not a vote. Respondents were self selected and the sample is not representative of any population. 429 of the 909 respondents to this question were companies. A different mix of respondents would give a different percentage. The GHG Protocol has not said that the result decides the outcome.

The working group comparison is between two different exercises. The indicative vote covered 43 experts who had drafted the proposal. The consultation covered 909 self selected respondents seven months later. The 41 point gap is real and the two groups are not comparable samples.

Two small groups carry no statistical weight. The 81% support among data and software providers rests on 21 responses and the zero support among assurance providers rests on 6. They are reported because they are published rather than because they are robust.

The deliverability percentages were not read. The summary of feedback carries a quantitative section on quality criterion 5 at section 13.2 and further quantitative data at section 13.7. Both sit on pages beyond the part of the file that could be read [1]. The executive summary describes low levels of support for deliverability and plurality support among several other groups [4]. Only the hourly matching percentages are quoted here.

The worked example is invented. It shows the arithmetic of an unmatched share and not a measured result for any portfolio. The residual mix factor used is one company published figure for Great Britain in 2024 and a landlord applying a different residual mix would get a different answer.

The research is not about UK property. The modelling studies cover United States and continental European systems and hydrogen production. The one buildings study uses United States grid data. They establish the direction of the effect and not its size in a UK portfolio. Several of the figures quoted sit in the full texts rather than in the abstracts. The Xu study was read through its abstract and its publisher record only.

The minutes carry a date discrepancy. The meeting 16 minutes are titled 25 June 2025 and the running page headers read 4 June 2025 [2].

What not to conclude. A market based zero reported under the 2015 criteria is a permitted figure and remains permitted. Low consultation support does not mean hourly matching has been rejected and the expert vote does not mean it will be adopted. Neither is a decision.