The GHG Protocol asks companies that buy electricity under contracts to report Scope 2 two ways. The two figures answer different questions, so MetricOra keeps them side by side and never adds them together.
Location-based: what the grid emitted
Location-based Scope 2 multiplies the electricity you used by the average emissions of the grid where you used it. For a UK site in 2025, MetricOra's DEFRA 2025.2 library uses 0.177 kg CO₂e per kWh. A quarter's meter reading at our demo head office is stored like this:
36,224.3 kWh × 0.177 kg CO2e/kWh = 6,411.70 kg CO2e
This is the figure SECR asks for, and it is the headline Scope 2 number on the dashboard and in reports.
Market-based: what you chose to buy
Market-based Scope 2 reflects the contracts behind your supply. In MetricOra you add them under Settings, then Electricity contracts: REGOs, power purchase agreements, green tariffs, a supplier's own emission rate, or a residual mix figure. Each has the site it covers, the dates it runs and, where relevant, the kWh it covers.
When a run calculates market-based electricity, it works through them in the GHG Protocol order:
- certificates and PPAs, never claiming the same certificate twice
- green tariffs
- the supplier's specific rate
- the residual mix
Any kilowatt-hours left uncovered fall back to the library factor, and the calculation says so.
Reading the two together
Our demo office has a REGO covering 130,000 kWh in 2025. Its location-based figure stays the same whatever contract it signs. Its market-based figure falls, because the certificates carry a zero emission rate. The gap between the two shows how much of the change comes from purchasing and how much from using less electricity.
That gap is why neither figure replaces the other. Location-based tracks efficiency at the site. Market-based tracks procurement decisions. Reporting both makes it clear which one moved.