What are renewable energy certificates (RECs)?
A renewable energy certificate (REC) is a market-based instrument representing the environmental attributes of 1 MWh of renewable electricity.
Why it matters
According to the US EPA, a REC is issued when one megawatt-hour of electricity from a renewable source is generated and delivered to the grid. It carries the rights to the environmental and other non-power attributes of that generation. Electricity on a shared grid cannot be traced to a particular plant, so certificates are how buyers back up renewable electricity claims.
Under the GHG Protocol Scope 2 Guidance, RECs and similar contractual instruments, such as guarantees of origin, feed the market-based method. The instruments and rules differ from market to market. Buying them does not change the physical generation mix of the grid, so location-based emissions stay the same.
An example
A company buys enough certificates to match a year of electricity used by its servers in a fossil-heavy region. Its market-based Scope 2 can then show close to zero for that electricity. The power stations feeding the region run as before, so its location-based figure, and the carbon intensity of each kWh it draws, do not change.
Where Greenpixie fits
Greenpixie's figures are location-based and describe the average generation mix of each grid area, hour by hour. Its methodology states they should not be combined with RECs, guarantees of origin or power purchase agreements to produce a market-based figure.
This keeps the figures tied to physical electricity use. A reduction shows up only when a workload uses less energy, moves to a cleaner region or runs at a cleaner hour.