Hourly carbon-free energy matching: 24/7 CFE and your interval data

Many organizations now report that they run on 100% renewable electricity. Look closely and the claim usually rests on annual matching: across a full year, the megawatt-hours of renewable energy purchased equal the megawatt-hours consumed. That accounting can hide a physical reality. A building drawing power at 2 a.m. is very likely running on whatever the grid dispatches at 2 a.m., which in most regions still includes fossil generation. Hourly carbon-free energy (CFE) matching exists to close the gap between the paper claim and the grid your meters actually pull from.

This is a reporting question, but it is really a data question. You cannot match consumption to clean supply hour by hour if your consumption is only known as a monthly total on a bill. The move toward 24/7 CFE puts a premium on granular, standardized interval data, and that is where most programs stall.

Annual matching versus hourly matching

Conventional renewable claims use volumetric (annual) matching with renewable energy certificates (RECs). Production and consumption only need to average out over the year, so a company can buy certificates from solar generated far away during the day and use them to offset load drawn overnight. As one policy analysis puts it, under annual matching the timing and location of generation do not have to line up with demand, so real-time grid emissions are not reflected in the claim.

Hourly matching, often called 24/7 carbon-free energy, is stricter. The 24/7 Carbon-Free Energy Compact, launched at the UN High-Level Dialogue on Energy in September 2021, defines the goal as every kilowatt-hour of consumption met with carbon-free electricity at every hour of every day, on every grid where you operate. Instead of a yearly balance, each hour is scored on its own.

In practice this means measuring a facility's hourly electricity use against carbon-free supply on the same regional grid in the same hour. If purchased carbon-free generation in a given hour meets or exceeds load, that hour counts as matched. Time-based, or time-stamped, energy attribute certificates (T-EACs) are the instruments used to verify that hourly relationship, in contrast to the annual RECs behind volumetric claims.

Why annual matching can overstate progress

The concern is not just precision for its own sake. Modeling from Princeton's ZERO Lab found that volumetric and emissions-matching procurement strategies can lead to zero or close to zero long-run carbon emissions reductions, because the clean energy bought largely displaces other renewables that would have been built anyway. Temporal (24/7) matching, by contrast, reduces system-level emissions because it requires carbon-free production even in hours when fossil resources would otherwise set the margin. The peer-reviewed version of that work appears in Cell Reports Sustainability.

The cost and impact tradeoff is real. In a California scenario with 25% commercial and industrial participation, the study found that volumetric and emissions matching produced roughly zero system emissions reductions at a modest premium, while 100% temporal matching produced significant cuts at a higher premium. The lesson for an energy or ESG lead is that a 100% annual claim and a high hourly CFE score are not the same achievement.

For context on the operator side, Google reported reaching 66% carbon-free energy on an hourly basis in 2024, up from 64%, with 9 of 20 grid regions at 80% or higher. Its stated goal is running on 24/7 carbon-free energy on every grid where it operates by 2030. Microsoft framed a similar hourly ambition in its 100/100/0 pledge to match 100% of its electricity use, 100% of the time, with zero-carbon energy.

Granular certificates and T-EACs

The instrument that makes hourly claims auditable is the granular certificate. EnergyTag, a non-profit, sets a voluntary standard for hourly matching and granular certificates, with criteria for hourly or sub-hourly time granularity, geographic deliverability, and prevention of double-counting. Where a conventional REC represents a megawatt-hour with no timestamp, a granular certificate carries the hour it was produced.

This market is now moving from pilot to infrastructure. In June 2025, EnergyTag accredited its first two official granular certificate schemes, describing them as the foundational tracking layer for hourly clean energy rather than a carbon-claims standard in themselves.

The standards are moving toward hourly

Voluntary schemes are one signal. The bigger one is that the GHG Protocol is revising its Scope 2 guidance. In its consultation, the proposed market-based method would require that contractual instruments be matched to electricity use on an hourly basis, with a narrow exemption for smaller organizations still to be defined. The same summary notes the guidance is expected to be finalized in late 2027, with an effective date some years after. The GHG Protocol announced the consultations on its own Scope 2 update page.

Hourly interval data is the foundation

None of this works without granular consumption data. Hourly matching depends on metered load at hourly or finer resolution, which is why the rollout of advanced metering and buyer access to interval energy data is what makes hourly accounting feasible at all. If your load is only visible as a monthly bill line, you cannot compute an hourly CFE score, and you cannot retire a granular certificate against a specific hour.

In our experience the practical blocker is rarely the certificate market. It is that a portfolio's interval reads arrive in different formats, with gaps, timezone ambiguity, and inconsistent units. Standardizing that data into clean hourly series is the unglamorous work that has to happen before any 24/7 claim can be defended.

Two attributes turn a raw interval read into a matchable record: an accurate timestamp in the correct timezone, and a consistent unit. A single missing interval, or a read that shifts silently across a daylight-saving boundary, breaks the hour-by-hour comparison and produces an unmatched hour you cannot explain to a reviewer. Deliverability adds a second constraint. A granular certificate only counts toward an hour if the clean generation behind it could physically reach your load on the same grid in that hour, which is why the EnergyTag criteria pair time granularity with geographic deliverability. Both tests are settled in the data layer, well before a certificate is ever retired.

The output of all this is a CFE score: the share of your annual load, hour by hour, that was met with carbon-free supply. Unlike a 100% annual claim, that score can sit anywhere below 100% even for a fully renewable-backed portfolio, because it exposes every hour where clean supply fell short of load. That honesty is the point. A CFE score gives an energy manager a concrete target for where to add supply, shift load, or add storage, rather than a binary claim that hides the remaining work.

How this differs from location-based accounting and offsets

Hourly matching sits inside the market-based world of Scope 2. It does not replace the location-based method, which uses grid-average emission factors to show your physical footprint. For that distinction, see our explainer on market-based versus location-based Scope 2. Hourly matching is also not a carbon offset: it is procurement of attributes for the electricity you actually use, not a credit for a reduction somewhere else. For that boundary, see RECs, offsets, and real reductions.