Hourly matching is an energy accounting approach that matches electricity consumption to renewable electricity generation (or energy attribute certificates) on an hour-by-hour basis, rather than using annual or monthly totals. It is used to make more credible claims about time-aligned renewable electricity, and it is increasingly relevant for EV charging networks that want to report when charging occurred and what kind of electricity was available at that time.
What Is Hourly Matching?
Traditional renewable electricity claims often rely on annual matching:
– A company consumes X MWh in a year
– It purchases and cancels X MWh of certificates (e.g., Guarantees of Origin (GO)) for that year
Hourly matching is stricter:
– Consumption is aggregated per hour (e.g., 14:00–15:00)
– Renewable generation (or certificates) is matched to the same hour
– The claim reflects whether renewable supply was available at the time of use, not just over the year
Hourly matching is often discussed in the context of “24/7 carbon-free energy” and more granular Scope 2 reporting ambitions.
Why Hourly Matching Matters for EV Charging
EV charging loads are time-dependent and often peak in the evening, when renewable generation may be lower in some grids. Hourly matching helps charging operators and fleets:
– Improve credibility of “renewable charging” claims beyond annual certificate coverage
– Identify when charging is most aligned with renewable generation
– Support carbon-aware charging strategies that shift charging to cleaner hours
– Provide more transparent sustainability reporting to corporate customers
– Differentiate premium charging offers (time-matched renewable or low-carbon charging)
For B2B customers, hourly matching can strengthen tender responses and ESG narratives—especially when paired with strong metering and audit trails.
How Hourly Matching Works
A typical hourly matching workflow includes:
– Collect hourly electricity consumption data (site meter or charger-level data)
– Obtain hourly generation data or hourly-tagged attributes (e.g., renewable generation profiles, certificate data where available)
– Match consumption and renewable attributes for each hour
– Report the matched share and identify uncovered hours
– Cancel certificates where applicable, following the chosen methodology and market rules
Where certificate systems are not hourly-granular, hourly matching may rely on a combination of contractual instruments, metered generation, and defined accounting rules.
Data Requirements for EV Charging Networks
Hourly matching depends on high-quality, time-stamped data:
– Accurate time-series kWh data per site or per charger
– Consistent time zone handling and daylight savings alignment
– Reliable telemetry from the CPMS and/or energy meters
– Metering suitable for billing and reporting (often MID metering in regulated contexts)
– Clear data governance for auditability (who owns data, how it is stored, how it is corrected)
Granularity matters: hourly matching is far easier when the system can export clean hourly datasets without gaps.
Hourly Matching vs Annual Matching
Key differences:
– Annual matching confirms total renewable coverage over a year, but not timing
– Hourly matching confirms time alignment, improving credibility and enabling operational optimization
– Hourly matching typically exposes periods where consumption is not renewable-aligned, which can drive smarter charging behavior and investment decisions (PV, grid-connected storage, tariffs)
Operational Implications for Charging
Hourly matching often leads operators to adopt:
– Smart charging schedules aligned with renewable-rich hours
– Time-of-use (TOU) tariff optimization combined with carbon signals
– On-site solar PV integration for daytime charging demand
– BESS for shifting renewable energy into evening peaks
– Customer-facing reporting (hourly matched share, emissions intensity trends)
Limitations to Consider
Hourly matching is more complex than annual approaches:
– Requires robust hourly data quality and consistent metering
– Market instruments may not provide perfect hourly traceability everywhere
– Methodologies differ by reporting framework and region
– Implementation adds operational overhead (data pipelines, auditing, certificate handling)
– Claims must be clearly defined to avoid confusion between “renewable covered annually” and “renewable matched hourly”
Related Glossary Terms
Guarantees of Origin (GO)
Energy Attribute Certificates
Scope 2 Emissions
Market-based Accounting
Carbon-aware Charging
Carbon Intensity
Renewable Charging
Time-of-Use (TOU) Tariffs
Smart Charging
MID Metering