Green energy certificates — whether sourced directly, ‘unbundled’ from the actual energy supply, or as part of a Power Purchase Agreement (PPA) or a supply contract — have long been key tools in corporate sustainability. These certificates give firms a simple way to offset their carbon-intensive power consumption and support the shift to clean energy in one go.
For years, it’s worked. If a company couldn’t source enough renewable energy in its local area, procurement could buy certificates and ‘match’ the megawatt hours they represented to actual consumption. The fees would help fund the broader transition to renewables.
Today we know the match was rarely perfect.
Certificates have been generated on an annual basis, forcing companies to try and link their real and green consumption retrospectively — a gargantuan undertaking when you factor in variables like wind and solar intermittency. It either results in undercounting the actual renewable energy used, or accidentally over-stating it.
Today’s Scope 2 standard was first defined over 10 years ago [...]. A number of very large companies already report “no emissions”, which doesn’t reflect what’s actually needed to get to zero emissions in society or in power systems.
– Killian Daly, EnergyTag, in the Plugged In podcast with Montel News and Renewabl
For certificates to deliver on their promise, something has to change.
Enter hourly matching
The imminent arrival of 24/7 carbon free energy (CFE) or ‘hourly’ matching is a big step forward. It proposes that companies align their renewable energy portfolios with their electricity demand on an hourly basis, matching a given volume of clean energy demand with an equal volume of clean energy generation — on or about the time the electricity was used.
With the GHG Protocol amending Scope 2 accounting rules, some worry that hourly-matching means replacing 100% matching annually with 100% matching at every hour of the day. Adding ‘24/7’ to the description might also suggest that actual consumption must be correlated to clean energy certificates hour by hour, every day of the week.
In reality, GHGP does not propose any specific targets. Such granular accounting starts with a new level of data visibility, allowing companies to gradually increase alignment, rather than demanding full correlation at all times.
It’s about increasing traceability and credibility in reporting. Currently, many corporates report on an annual basis. We are moving toward more precise spatial (locational) and temporal (hourly) matching, so you can say that every hour of consumption you report as clean is matched by actual clean production.
– Carolyn Addy, Renewabl
It’s also distinct from carbon offsets, which subsidise emission reductions elsewhere rather than aligning clean energy procurement with actual use.
Let’s try and clear up any confusion.
How does it work?
Hourly matching differs from other clean energy procurement methods by matching demand to consumption on an hourly (and eventually sub-hourly) basis. To guarantee a match, corporations acquire energy certificates with a time stamp of one hour from renewable generators, usually validated by meter and grid data.
In the UK, clean energy certificates are called Renewable Energy Guarantees of Origin (REGOs) and issued by the Office of Gas and Electricity Markets (Ofgem). In the European Union they’re called Guarantees of Origin (GOs) and are issued by a number of EU accredited national bodies.
Generators apply for certificates to be issued and sell them to energy consumers, either in a form of unbundled REGOs / GOs, as part of a green tariff or a long-term agreement (PPA). EACs function as a commodity, so can be traded like power on the over-the-counter (OTC) market.
24/7 CFE introduces the need for a revised certification scheme called Granular Certificates (GCs) or T-EACs. While issuing bodies and regulations are working to introduce GCs, the calculations and transactions can be done on a digital platform like Renewabl.
Hourly matching, 24/7 CFE, granular accounting: same idea, different language
You will often see 24/7 carbon-free energy (CFE), hourly matching, and hourly (or granular) accounting used almost interchangeably because they describe closely connected parts of the same idea. Different organisations emphasise different aspects, which is why the language can feel crowded.
24/7 carbon-free energy (CFE) is the goal. It means using carbon free generation in the same grid and the same hours that electricity is consumed — not just claiming renewables on an annually matched basis, but aligning electricity use with clean supply across all 24 hours of the day. This framing is used by Climate Group’s 24/7 Carbon-Free Coalition and Google in their public reporting.
Hourly renewable energy matching (often shortened to hourly matching or hourly CFE matching) is the practical method. It focuses on electricity matching at a granular level, aligning demand with renewable supply hour by hour instead of relying on annually matched volumes. We at Renewabl use this term because it is simple and clearly describes what needs to be done to reach the desired objective.
Hourly (or granular) accounting is the measurement and reporting layer. It is how hourly electricity matching is quantified, verified, and disclosed under frameworks including GHG Protocol Scope 2. By applying granular accounting, companies can see when their electricity is clean, identify gaps, and report progress credibly to stakeholders.
In short: 24/7 carbon-free energy is the objective, hourly CFE matching is how it is achieved, and hourly accounting is how that progress is measured and reported.
How do you get started?
1. Get your data ready
Your consumption is not constant and isn't always in sync with renewable energy generation.
Start by introducing more precise approach to energy data management. This means pulling hourly demand from your suppliers or smart metres, and getting generation or certificate data from your existing contracts. Analyse the performance of your existing contracts as well as when and where you need electricity for business operations. You don’t need to change your procurement strategy at this stage – the focus is on visibility, not targets.
See an example of how a wind PPA vs solar PPA cover the demand curve of a sample energy buyer (source: Renewabl's platform):
2. Measure your baseline 24/7 CFE score
Calculate the overall level of matching between your consumption and clean energy generation on an hourly or sub-hourly basis to generate a carbon free energy (CFE) score. Platforms like Renewabl Track can do this calculation for you – see Renewabl's methodology for calculating the hourly CFE score alongside emissions avoided.
3. Educate the board and internal teams
Share what the GHG Protocol Scope 2 update and other regulatory frameworks are moving towards and why hourly accounting matters. Most teams find it helpful to see their own demand curve next to their PPAs or certificates. It makes the discussion concrete and brings finance, sustainability and procurement onto the same page.
4. Stress-test procurement options
Once the data is in place, buyers start looking at how different PPAs, tariffs or storage options fit their demand curve. The aim is not to jump to 100% coverage but to test what a mix of solar, wind or storage would do to both your CFE score and your risk position.
5. Pilot hourly claims in one site or country
Most organisations begin with a small pilot. They may run a tender for granular certificates or take the learnings into account when signing a new PPA, then track hourly performance for a few months. It’s enough to learn how the accounting works and what “good” looks like for your specific load shape.
"The challenge is to find certificates that address factors like the desired percentage of renewable energy, preferred type of generation, geographic location, or the times of day when demand tends to rise or fall."
– JP Cerda, Renewabl
6. Make your matching and reporting scalable
After the pilot, buyers bring more sites into scope and set internal expectations for what a good hourly CFE score should be. At Renewabl, we see many organisations in energy-intensive industries aiming for hourly CFE score of 60-70% as they start. Moving further, if you’re on a path to net-zero the goal should be 80-90%. The final 10-20% can be addressed when certificates are issued in increments of 30 minutes or less, something likely coming in the next few years.
The key is that the system can scale — the reporting becomes consistent and your procurement decisions become easier.
"Renewabl’s online marketplace enables you to search for clean energy certificates using all these variables and more, then purchase them in the volumes you need."
– JP Cerda, Renewabl
Procurement options for hourly matching
To achieve credible Scope 2 emissions reductions, companies can choose from several renewable energy procurement methods, each with its own risks and benefits. This section outlines key options, from simple solutions to more complex arrangements. Each method can be tailored to fit a company’s energy strategy and sustainability goals.
Unbundled Energy Attribute Certificates (EACs / REGOs / GOs)
An EAC represents one megawatt-hour (MWh) of renewable electricity. Unbundled EACs are sold separately from the physical electricity and are typically used to meet Scope 2 decarbonisation goals.
While most EACs have been sold annually, new platforms now offer hourly-matched EACs using real-time generation data. This allows for more accurate, data-driven matching of clean energy to actual consumption, increasing transparency and credibility.
Hourly matching with EACs is one of the most cost-effective ways to achieve compliance and demonstrate a genuine commitment to renewable energy, even if registries haven’t yet adopted hourly time-stamping. Independent platforms, like Renewabl, enable precise clean energy tracking by using granular certificates (GCs) that provide exact hourly production data.
Hourly matched electricity supply contracts ('green tariffs')
Suppliers offer contracts where companies pay a premium to ensure electricity comes from renewable sources, often supplemented by EACs. Fixed-price contracts are typically load-following, adjusting energy volumes to meet fluctuating demand. Larger energy users may opt for flexible contracts, buying power in blocks and adjusting purchases to optimise costs based on market conditions.
For hourly matching, larger suppliers — especially those with renewable generation and storage portfolios — can curate assets to match a buyer’s unique demand profile. While these contracts offer greater flexibility, they tend to come at a premium due to the need for more diverse renewable assets and the integration of higher-cost technologies like battery storage.
Hourly matched Power Purchase Agreements (PPAs)
PPAs are long-term contracts where a buyer commits to purchasing renewable energy from a developer at a set price for a specified term. They offer stability and long-term sustainability benefits, but are typically best suited to larger buyers due to contract lengths and financial guarantees required by developers. Smaller buyers may find it challenging to meet the financial criteria.
There are various types of PPAs, including on-site, off-site, physical, virtual, and more. Learn more in our in-depth article on Power Purchase Agreements.
Hourly matching with PPAs is growing in popularity, as companies look to align specific demand profiles with renewable generation data from the supplier.
“Flexibility is driving demand — we’re seeing shorter tenures, mixed technologies, and rising interest in certificates alongside traditional PPAs.”
– JP Cerda, Renewabl
Buyers can assess projects through tenders, providing aggregate demand and historical generation data to find the best fit for hourly matching. Though these contracts involve more complexity and longer-term commitments, they provide high-impact renewable sourcing and can help hedge against price fluctuations over time.
The costs and ROI of hourly matching renewable energy
Hourly matching for carbon free energy starts with how you report, not what you buy. The current GHG Protocol Scope 2 update focuses first on hourly accounting. In practice, that means lining up your electricity demand with your existing clean supply on an hour-by-hour basis. The main cost at this stage is time: getting hourly data from your energy suppliers, pulling in your metre data, and bringing it together in one place. Your energy procurement strategies do not need to change straight away.
Costs change when you aim for a higher hourly match. Most buyers begin by improving their mix rather than jumping to 100% 24/7 carbon free coverage. Eurelectric study based on real examples shows that a blend of wind and solar, instead of a single-technology PPA, can reach around 60–75% hourly coverage. Another study shows that hourly matching scores of up to 90-95% can be achieved with only a small cost premium compared to annually matching 100% renewable energy. The expensive part is usually the final 5–10% and it may need either storage and/or demand flexibility on top.
There is also a clear financial angle as power prices settle each hour. A diverse energy portfolio encouraged by hourly matching can stabilise electricity prices and act as a hedge against market volatility. If your supply only covers some hours, you still buy the rest at the spot price — that is where unexpected costs and negative price risk appear. Better hourly matching means fewer uncovered hours, fewer surprises from price swings, and more stable budgets.
According to the study by Eurelectric and Pexapark, a buyer with a wind, solar and storage PPA saved about €14 million in 2022 because their hedge covered more of the volatile hours.
So the return on hourly matching has two sides. You get stronger Scope 2 reporting and a clearer 24/7 carbon-free profile. At the same time, you build a hedge that follows your real demand curve. Platforms like Renewabl help buyers see this link in practice by placing hourly load data next to each project or certificate option before they sign.
Learn more about hourly matching and hedging correlation from Renewabl's recent webinar with Enery and BloombergNEF:
Why is hourly matching important?
Hourly matching will become a priority for corporate energy buyers very soon. Coming regulation around sustainability disclosures will essentially make it a requirement for compliant ESG reporting.
In nutshell, any claims a company makes about its renewable energy consumption will need to be backed by detailed data. Short of having major onsite capacity, a renewable generation plant nearby, or PPAs that cover 100% of your needs, corporates will have gaps to fill.
"GHG Protocol is voluntary — it’s a choice of accounting standard. But it also underpins initiatives like SBTi, RE100, and CDP, so most of those target‑setting frameworks use GHG Protocol rules."
– Carolyn Addy, Rebewabl
Clarity and transparency
Annual matching leaves energy buyers open to greenwashing accusations because transparency is harder to achieve. Every organisation has a unique consumption profile that blends multiple generation sources. With annualised certificates, green generation could theoretically be matched with consumption across a 12-month window, day or night — something likely to raise eyebrows if solar is in the mix.
"Green credentials may seem to be taking a back seat right now — but if you think you can get away without them, it will come back to bite you."
– Laurent Segalen, Megawatt-X / Redefining Energy, at Renewabl Day in London
Addressing intermittency
Moving to hourly matching could also help overcome the intermittency problem. Using annual certificates, a corporate buyer could stick with the firm’s traditional load profile while claiming to be 100% powered by renewables. Though accurate on paper, it would ignore the reality of fluctuating carbon-free electricity on the grid during periods when renewables aren’t abundant and prices tend to be higher.
The growing demand for renewable power during the hours of scarce generation, like winter evening, will send the right demand signals to the systems so we can more closer to a fully decarbonised electricity system. The adoption of hourly matching strategies is expected to accelerate the development of advanced technologies like energy storage.
Stoking internal demand
There is also hope that reporting a company’s level of hourly matching will create internal pressure to push whatever fossil fuel generation remains out of the consumption profile. As the percentage of hourly matching increases, demand for more flexible net-zero production and demand response will grow too, helping overcome a key barrier to the renewables transition.
Why regulations are moving towards 24/7 Carbon-Free Energy or hourly matching
The movement towards 24/7 CFE is gaining momentum as a response to the urgency of the climate crisis. Regulators want more detail, and hourly matching prevents "greenwashing" by ensuring real-time carbon-free energy consumption, providing a more accurate view of actual emissions.
The EU’s rules for renewable hydrogen set the tone by requiring hourly matching between consumption and production. This same direction appears in wider energy policy, including the changes proposed under the GHG Protocol Scope 2 update, which is now in public consultation. The United Nations has launched a 24/7 Carbon-Free Energy Compact to promote the principles of 24/7 CFE.
The Scope 2 revision introduces time-based and regional matching for market-based reporting. Annual certificates will not give enough evidence on their own. Buyers will need data that shows which hours were clean and which hours were not. This approach brings reporting closer to real grid behaviour and makes claims easier to verify.
European policy work around Guarantees of Origin also signals this shift. Shorter issuance periods, tighter disclosure rules and more direct links between certificates and consumption support a move away from broad annual averages. We cover these changes in more detail in our explainer on changing EU regulatory frameworks.
Climate Group have two initiatives linked to clean energy. The commitment to Climate Group's RE100 must be supported by either net-zero self-generation or electricity purchased from net-zero sources, including green energy certificates.In 2024, Climate Group launched the new 24/7 Carbon-Free Electricity Coalition which promotes the importance of hourly matching.
What are the challenges of moving to hourly matching?
Perceived complexity
Implementing hourly matching requires access to large volumes of granular, time-stamped data on energy generation and consumption. This can be easier in the countries where companies can utilise smart meter data to track consumption in intervals of 15, 30, or 60 minutes for hourly matching.
While there is positivity, there’s also a realistic appreciation of the work required.
– Carolyn Addy, Renewabl
Buyers also need to understand the mechanics of obtaining hourly certificates, adopt best practices to ensure the price and choice of supplier is optimised, and then apply the certificates strategically to support net zero goals.
The need to determine the organisation's electricity consumption mix
To benefit from hourly matching you first need to gather your current consumption data and create a consumption profile.
It will answer important questions like:
- What proportion of your power comes from renewables, non-renewables, self-generation from on-site solar arrays, or via PPAs?
- To what extent is intermittency a factor in energy supply?
- Does the local grid have reliable sources of green energy?
Most of the consumption data is readily available through smart metres, your PPA agreements and any certificates you own currently. The answers will show you where hourly matching can help fill the gaps.
Getting hold of the certificates you need
While Ofgem issues a wide variety of hourly certificates, finding certificates that fit your company’s consumption profile can be challenging.
How can Renewabl help?
Many organisations still consume a proportion of electricity from plants that burn fossil fuels, making it harder to achieve corporate net zero commitments.
REGOs / GOs and PPAs have been a useful tool for compensating carbon-intensive grids while providing a level of funding for new renewable capacity, but their effectiveness has hit a ceiling. Coming regulation will soon render annualised green energy certificates impractical as a way to source clean energy. Hourly matching is coming.
In order to take advantage of hourly matching, energy buyers can now purchase certificates on an hourly basis. The challenge is to find certificates that address factors like the desired percentage of renewable energy, preferred type of generation, geographic location, or the times of day when demand tends to rise or fall.
Renewabl’s platform enables you to search or run a tender for clean energy certificates using all these variables and more, then purchase them in the volumes you need.
Want to find out more?
– With files from Renewabl contributor Mark de Wolf.
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