Two ways to count the same electricity
The GHG Protocol's Scope 2 Guidance gives two methods for counting the emissions from electricity you buy. Where certificates like REGOs exist, as in the UK, it asks companies to report both.
| Method | What it measures | Factor used | Effect of a green tariff |
|---|---|---|---|
| Location-based | The emissions of the grid you actually draw power from | The UK grid average: 0.13096 kg CO2e per kWh in 2026 | None |
| Market-based | The emissions of the electricity you have chosen to buy | Zero for supply backed by REGOs; otherwise your supplier's fuel mix factor, or the grid factor if you have neither | Can bring Scope 2 to zero |
Neither figure is wrong. They answer different questions. Location-based tells you what your electricity use does to the grid you are connected to. Market-based tells you what your buying choices support.
What REGOs do, and don't do
A REGO, or Renewable Energy Guarantee of Origin, is a certificate showing that a unit of electricity was generated from a renewable source. When a supplier sells you a renewable tariff, it should be able to match your usage with REGOs. That is what lets you report zero market-based emissions.
What a REGO doesn't do is change the electricity coming down your wire. Your office still draws from the same grid as before, so your location-based figure is the same whatever tariff you are on. A tariff with "green" in its name but no REGOs behind it doesn't change your market-based figure either, so ask your supplier for confirmation.
A worked example
An office uses 40,000 kWh of electricity in 2026 and switches to a REGO-backed renewable tariff.
| Figure | Calculation | tCO2e |
|---|---|---|
| Location-based Scope 2 | 40,000 kWh × 0.13096 | 5.24 |
| Market-based Scope 2, REGO-backed tariff | 40,000 kWh × 0 | 0.00 |
| Location-based, after cutting use by 6,000 kWh | 34,000 kWh × 0.13096 | 4.45 |
The Carbon Reduction Plan shows 5.24 tonnes for Scope 2, tariff or no tariff. What brings the plan's figure down is using less electricity (better lighting, controls, efficient equipment) or generating your own on site, because solar power you use yourself never comes through the meter.
If you are not on a renewable tariff
You still have a market-based figure. Electricity suppliers publish a fuel mix disclosure showing where their power comes from, and many also give an emissions figure in grams or kilograms of CO2e per kWh. Use that as your market-based factor if you have it. If you don't, the market-based figure falls back to the grid average, so both of your Scope 2 numbers will be the same. That is fine: report both, and say which method each one uses.
What to report
- In a Carbon Reduction Plan: Scope 2 location-based in the emissions tables. If you are on a renewable tariff, you can mention the market-based figure in the text, clearly labelled.
- In an SECR report: location-based as the main figure, with market-based alongside if you have a renewable tariff.
- To a customer questionnaire: give both if the form allows, and say which is which.
Never quietly swap one for the other. Showing a green tariff as a reduction without saying so is listed in our PPN 006 guide as a common reason plans get marked down.
Watch the grid factor too
The location-based factor changes every year. It fell from 0.177 kg per kWh in 2025 to 0.13096 in 2026, so the same 40,000 kWh produced 7.08 tonnes in 2025 and 5.24 in 2026. That is real, but it isn't your doing, so explain it rather than claiming it. Our guide to the 2026 conversion factors explains the change, and the electricity emission factor page has every year since 2019.
How Carbon Recycling helps
Carbon Recycling calculates both Scope 2 figures from the same electricity data. Tick the renewable box on a bill only if your supplier can show REGOs, or enter your supplier's fuel mix factor, and the market-based figure updates while the location-based figure stays on the grid average. The Carbon Reduction Plan reports Scope 2 location-based, and the SECR report shows the market-based figure alongside.