Draft:Hourly Matching V1

A corporate carbon accounting method From Wikipedia, the free encyclopedia

Hourly Matching

Hourly matching (also called 24/7 hourly matching, granular matching, or CFE matching) is an emerging approach to energy accounting that links an organisation's electricity consumption to actual renewable power generation on an hourly basis.

It replaces the process of annual matching, whereby renewable energy generation and consumption are balanced using totals accumulated over a year. Advocates of the approach say it aligns corporate renewable energy claims more closely with the timing of actual power production on the electrical grid, painting a more accurate picture of the carbon intensity of a firm’s electricity use.

To verify sustainability claims related to clean energy consumption, many organizations quantify renewable electricity consumption by purchasing energy attribute certificates (EACs) such as Renewable Energy Certificates (RECs) in North America or Guarantees of Origin (GOs) in Europe. Issued by recognized statutory bodies, EACs measure renewable generation and electricity consumption on an annual basis, regardless of the day or time-of-day when the energy was generated.

The concept of hourly matching is associated with initiatives from firms like Google and Microsoft to promote 24/7 carbon-free energy, and spearheaded by non-profit industry associations including EnergyTag, which develop technical standards for clean energy accounting.

Background

Scope 2 emissions accounting

Current certificate systems ‘match’ renewable generation and consumption over an annual accounting period, regardless of when the electricity was generated or consumed. In the early 2020s, researchers and policymakers began exploring new carbon accounting approaches that would align renewable energy procurement more closely with the temporal characteristics of generation and consumption.[1]. Those discussions led to proposals for new, granular accounting methods that would strengthen net zero and sustainable operating claims, culminating in the Greenhouse Gas Protocol (GHG).

Under GHG, corporate carbon reporting separates emissions into Scope 1 (emissions due to owned operations), Scope 2 (indirect emissions due to electricity procurement), and Scope 3 (emissions attributed to a company’s supply chain) [2].

To address Scope 1 reporting and prove that a given quantity of electricity has been generated from renewable sources, organizations typically use EACs to substantiate renewable energy claims, which correspond to one megawatt-hour (MWh) of renewable electricity generation. EACs are purchased and then ‘retired’ (or ‘cancelled’) after use, ensuring no double counting took place.

To address Scope 2 reporting, organizations must adopt two distinct approaches: location-based and market-based [3].

1. Location-based method: Instead of relying on EACs, this method reports the average emissions intensity of the local grid where energy is consumed, using average emission factors (often called grid-average data) provided by national or regional authorities. This is mandatory for all companies, as it represents the physical reality of the electricity being used, regardless of who the supplier is.

2. Market-based method: This method reports emissions from the actual generation sources companies have purchased energy from. EACs are commonly used as the backup or proof to support reported figures. Power Purchase Agreements (PPAs), long-term, direct contracts with renewable generators, may also be used.

In some cases, electricity suppliers can provide a specific emissions figure based on their entire energy portfolio, which might be lower than the grid average. Utilities may offer a special green energy tariff backed by EACs to ensure they are not double-counted.

Scope 3 reporting represents the next frontier of hourly matching, with particular challenges related to lower data availability and higher audit risks.

Hourly matching explained

Definition

To achieve hourly matching, a company’s renewable energy use is matched by the hour to renewable power generated in the same period. That means a megawatt hour of power consumed between 7pm and 8pm is matched to a megawatt hour of power generated in the same time frame. As a carbon accounting methodology it aims to align a firm's electricity demand with corresponding renewable generation, ideally from the same local grid.

Matching consumption and generation to the hour better reflects variations in generation types across different hours of the day (e.g., solar power can’t be generated at night), and provides a more accurate depiction of the carbon intensity of electricity use. [4].

The US Green Hydrogen Organization defines hourly matching as having Three Pillars [5]:

Hourly matching (temporal correlation): Requires that electricity consumption be matched with carbon-free energy (CFE) production in the same hour. This prevents "paper greening," where a company claims 24/7 green energy based on annual averages while actually relying on fossil fuels during off-peak hours.

Deliverability (geographic correlation): Mandates that clean energy be generated within the same physical grid region as the consumer. This ensures that the energy being purchased can physically reach the user, accounting for transmission constraints.

Incrementality (additionality): Requires that the clean energy comes from new generation assets (typically built within three years of the load). This prevents existing renewable resources from simply being diverted from the current grid to a specific project, which would otherwise force the grid to fill the gap with fossil fuels.

Terminology

The varied language used to describe hourly matching can cause confusion. The term is used interchangeably with ‘24/7 carbon-free energy (CFE)’, and ‘hourly (or granular) accounting’. Each term describes closely-connected aspects of the same broad concept. Different organisations emphasise different aspects.

24/7 carbon-free energy (CFE) best describes the goal of hourly matching. It means using carbon free generation in the same grid and the same hours that electricity is consumed. This framing is used by Climate Group’s 24/7 Carbon-Free Coalition [6] and Google in their public reporting.

Hourly renewable energy matching (often shortened to hourly matching or hourly CFE matching) is the practical method for achieving that goal. It focuses on electricity matching at a granular level, aligning demand with renewable supply hour by hour instead of relying on annually matched volumes.

Hourly (or granular) accounting refers to measurement and reporting, describing how hourly electricity matching is quantified, verified, and disclosed under frameworks including GHG Protocol Scope 2.

Mechanism

Hourly matching integrates and cross-references time-stamped data for both electricity consumption and renewable energy generation. Advanced metering systems [7] capture electricity use at hourly or even sub-hourly (30 minute) intervals, while renewable generation is also tracked with temporal data attached. Organizations then purchase electricity from renewable sources corresponding to the specific hours in which the electricity is used.

To achieve renewable energy consumption targets, corporate energy buyers sometimes need to blend different generation formats such as wind, solar, or hydropower. They might also need to incorporate battery storage or demand management systems. Hourly matching facilitates this sort of flexibility in a firm’s procurement mix by capturing different generation modes as they’re used, enabling more accurate reporting.

Technically, the match is executed by a firm’s energy management or sustainability department when reporting, either in a table format such as Excel or via digital platforms that align consumption and demand data. There are technology startups that are building the infrastructure for hourly matching and shorter-interval clean energy supply including Matched Energy, Renewabl, and Reel Energy.

Granular energy certificates

One key enabler of hourly matching is the development of granular energy certificates (GECs). Based on proposals from industry organizations like EnergyTag[8], GECs are designed to complement or extend current RECs, which operate on annual or monthly accounting periods. GECs embed data about the specific time and location of each MWh of renewable power generation.

Hourly matching scores

An hourly matching or CFE score is used to capture the percentage of an organization's power consumption matched by CFE within a regional grid. It can be measured annually, monthly, weekly, or hourly, though hourly resolution is increasingly the objective. Scores for longer periods (daily, monthly, annual) can be derived as volume‑weighted averages of hourly matching.

Calculations typically factor in load (the buyer’s electricity demand for the period, measured in megawatt hours, contracted CFE (the amount of carbon-free energy purchased by the buyer, and default delivered CFE (CFE in the electricity utility/supplier mix that has not been voluntarily procured by corporate buyers but is delivered by default).

Hourly matching initiatives

The first proponents of hourly matching were large electricity consumers looking for better ways to back up claims that their corporate net zero commitments were being met. Initiatives like the 24/7 Carbon-Free Energy Compact, coordinated by the World Resources Institute; Climate Group's 24/7 Carbon-Free Coalition; and Eurelectric's Next-Generation CFE Hub, have brought businesses, utilities, and governments together in support of time-based energy procurement frameworks [9].

Private sector initiatives to advance hourly matching include an announcement by Google that it will shift to 24/7 carbon-free energy by 2030. In practice that will require all its electricity demand to be matched against carbon-free sources – at all times and in every location where it operates a data center [10].

Microsoft has also stated an ambition to achieve 100% carbon-free electricity on a 24/7 basis by 2030, which includes procurement strategies that incorporate time-based matching of electricity consumption with renewable energy sources [11].

Non-profit initiatives include the UK’s Matched Energy initiative, which provides verifiable ratings of the renewable electricity UK suppliers actually deliver, hour by hour [12].

Regulatory and accounting standards linked to hourly matching

Adding weight to these goals and initiatives are moves by regulators to make hourly matching an operational requirement.

First is the EU's Carbon Border Adjustment Mechanism (CBAM), a regulatory framework which is promoting implementation on a practical level. As of January 2026 it requires that listed energy-intensive products imported with production-related emissions (ex. electricity, cement, iron or steel) be matched on an hourly basis in order to support any overall low-carbon emission claims.

Second is an emerging EU regulatory framework proposing an Energy Efficient Rating Scheme for Data Centres [13]. It would see implementation of 15-minute temporal matching and same bidding zone requirements for GOs used by data centres within the rating scheme’s jurisdiction.

The GHG Protocol is also in the midst of updates and additions that could lead to its most significant revision in over 20 years. A coordinated update is underway to revise the protocol's Corporate Standard and Scope 2 Guidance, embedding changes that would demand greater temporal and spatial alignment between contractual instruments (e.g., RECs) and actual electricity consumption.

Implementation and infrastructure

To make hourly matching a reality, firms will need high-resolution consumption data captured by advanced metering and digital grid systems [14]. Hourly generation data and information relating to grid carbon intensity at specific times and locations are also seen as key requirements [15].

Certificate registries will play a central role by issuing and tracking time-specific energy certificates. Emerging systems propose the use of metadata such as timestamp, generation source, and grid location.

Hourly matching also has implications for electricity markets and procurement contracts. For example, new power purchase agreement (PPA) formats may be needed that align with hourly demand profiles. Markets could also emerge for trading time-specific energy attributes [16]. In wholesale electricity markets, hourly matching could lead to more flexible generation, energy storage, and demand response, reflecting the need to balance renewable supply and consumption across different times of day [17].

Policy and regulatory developments

Guidance from regulatory bodies and voluntary corporate climate initiatives have played a major role in the development of hourly matching [18]. Multiple efforts are underway that aim to improve the accuracy, transparency, and comparability of corporate climate disclosures, while balancing considerations related to cost, feasibility, and market design.

The Greenhouse Gas Protocol has recently initiated reviews of its Scope 2 emissions reporting requirements to consider time-based approaches [19].

Regulators and energy policymakers have also examined the role of time-based energy tracking and making it part of disclosure requirements.[20].

Debates and criticisms

Arguments against hourly matching

Critics of hourly matching note concerns about increased cost and complexity, plus a lack of market readiness [21]. For example, implementing time-based matching may require some firms to invest in new data infrastructure, switch to new procurement models, or re-write energy procurement contracts – any of which could could create unintended operational issues or add to transaction costs [22].

In regions where grids are relatively low-carbon, the incremental benefits of hourly matching may not justify the business risks [23]. There may also be disparities in the available market infrastructure for hourly energy attributes, which could limit the scale of rollouts and necessitate different reporting regimes for different regions [24].

Some researchers add that it's too soon to abandon annual matching frameworks completely, as they have delivered proven system-wide benefits by supporting investments in new generation capacity [25]. From this perspective, a shift to hourly matching may prioritize precision in reporting mandates over broader goals around grid decarbonization [26].

Arguments in favour of hourly matching

Supporters argue that, as a carbon accounting methodology, hourly matching allows firms to report the carbon intensity of their electricity consumption more accurately [27]. Tracking consumption and generation by the hour, and linking both with verifiable data, also captures fluctuations in grid emissions during different times of day. [28].

Another argument in favour of hourly matching is that it addresses longstanding concerns about the potential for mis-use in carbon accounting systems that rely on annual averages. Many observers believe annual matching may overstate the decarbonization impact of a firm’s power procurement. Because hourly matching provides granular tracking backed by time-tamped data, it would reduce attempts at greenwashing and improve the credibility of corporate sustainability reporting </ref>https://circulareconomy.europa.eu/platform/sites/default/files/greenwashing-policy-paper.pdf</ref>.

Advocates also say that industry-wide adoption would boost investment in a broader range of low-carbon technologies, including dispatchable generation, battery energy storage systems (BESS), and energy management systems that enable demand-side flexibility.

In the context of energy price volatility caused by geopolitical strife, hourly matching could lead to more resilient and price-stable electricity grids. This would be especially beneficial in Europe, where gas-fired generation continues to set marginal prices in many markets in the hours when renewables generation is lowest.

Pro hourly matching voices also believe it could provide an additional hedging avenue for power purchase agreements, leading to more cost stability for corporate power procurement teams, both generally and in times of crisis.

Evidence for this idea can be found in the different PPAs agreed by firms BASF and IKEA prior to the start of the Ukraine war. BASF reported approximately €2.7 billion in additional/unplanned European energy costs in 2022 [29]. IKEA, which had been building out contracted renewable capacity since 2009, was paying at least 50% below market rates in some markets during the same period [30]

Related concepts

Related Articles

Wikiwand AI