Rooftop solar: what it does to your Scope 2

Rooftop solar cuts your Scope 2 emissions by the grid electricity you no longer buy: each kWh of solar you use on site saves 0.13096 kg CO2e at the 2026 UK grid factor. Power you export doesn't reduce your gross Scope 2 under the GHG Protocol, so the more of your own generation you use, the bigger the cut.

Updated 19 October 2026 by the Carbon Recycling team. Figures use the official UK government conversion factors and are checked against the current gov.uk guidance.

How solar shows up in your footprint

Scope 2 covers electricity you buy. Solar panels you own produce power without burning anything, so there is nothing to report in Scope 1, and the power you use yourself never passes through your supplier's meter. The effect is simple: your grid imports fall, and so does your Scope 2.

Generation splits three ways, and each is treated differently:

Solar power that is...	Effect on Scope 2	Effect on total energy use
Used on site	Cuts it: you import less from the grid	None: it still counts as energy you used
Exported to the grid	None on the gross figure (see below)	Not counted
Used on site, but with its certificates sold	Market-based: you can't count it as zero-carbon; the GHG Protocol gives it the residual mix factor	None

The GHG Protocol's Scope 2 Guidance asks you to use your total, or gross, grid purchases, not purchases net of what you export. Your total energy consumption includes the solar power you used yourself as well as what you imported.

A worked example

An office imported 40,000 kWh of grid electricity a year. It installs solar panels that its installer expects to generate 12,000 kWh a year. 9,000 kWh is used in the building during the day and 3,000 kWh is exported. These are example figures: your installer's estimate and your half-hourly data will give yours.

	Grid import	Scope 2 (location-based, 2026)
Before solar	40,000 kWh	5.24 tCO2e
After solar	40,000 − 9,000 = 31,000 kWh	4.06 tCO2e
Cut	9,000 kWh	1.18 tCO2e (22%)

Each kWh used on site is multiplied by the 2026 grid factor of 0.13096. The 3,000 kWh exported doesn't change the gross figure. Total energy use is still 40,000 kWh: 31,000 kWh from the grid plus 9,000 kWh from the roof.

What about the power you export?

Here the two main sources of guidance differ, so be clear which you follow:

GHG Protocol: exports are left out. You report gross grid purchases, and power sold back to the grid isn't deducted.
UK Environmental Reporting Guidelines (2019): you may report an emissions reduction, in a net figure, for renewable electricity you generated and exported, calculated with the grid average factor. Total reductions from exports and green tariffs must not be more than your gross Scope 2. The guidelines say this section is still under review.

In the example, the exported 3,000 kWh would be worth 393 kg CO2e on that net basis. The safe approach: report gross Scope 2 as your headline, and if you show a net figure, label it and say how you got it. A PPN 006 Carbon Reduction Plan reports Scope 2 on the location-based basis, so use the gross figure there. The GHG Protocol is also revising its Scope 2 guidance and has consulted on changes, so check for updates before each report.

Use it, don't export it

In the example, 75% of the generation is used on site. The higher that share, the bigger the Scope 2 cut. Running flexible loads such as hot water, EV charging or dishwashers in the middle of the day raises it. Exported power still earns money: under the Smart Export Guarantee, suppliers that offer a SEG tariff must offer it to eligible generators, including solar installations in Great Britain of up to 5 MW. Each supplier sets its own rate, which must stay above zero, so Ofgem advises shopping around.

If someone else owns the panels

Under a rent-a-roof or power purchase deal, a third party owns and runs the panels and sells you the power. The GHG Protocol treats this as a direct line purchase: the power is Scope 2 for you, and the generation belongs to the owner. Ask the provider for the kWh supplied each month and whether they keep or sell the certificates, because that affects your market-based figure.

How Carbon Recycling helps

Enter the electricity you import from your bills, as before, and Carbon Recycling calculates location-based and market-based Scope 2 from it, so the drop after the panels go in shows straight away against your baseline. Record the installation as a completed measure in your Carbon Reduction Plan. Solar pairs well with the other measures in this series, LED lighting and heat pumps, and our post on location-based and market-based figures explains the two Scope 2 numbers.

Frequently asked questions

Do solar panels reduce Scope 2 emissions?

Yes, by the grid electricity you no longer buy. Every kWh of solar power you use on site is a kWh you don't import, worth 0.13096 kg CO2e in 2026 on the location-based method.

Is electricity from my own solar panels Scope 1 or Scope 2?

Neither. Solar panels burn no fuel, so power you generate and use yourself has no Scope 1 emissions, and because you didn't buy it, it isn't Scope 2 either. Only the electricity you still import from the grid is Scope 2.

Can I subtract the electricity I export from my footprint?

Not under the GHG Protocol, which says to use gross grid purchases and leave exports out of your inventory. The UK government's 2019 Environmental Reporting Guidelines do let you show a reduction in a separate net figure for exported renewable electricity, capped at your gross Scope 2. Report the gross figure first and label any net figure clearly.

Does solar reduce my SECR energy use?

Not the total. Under the GHG Protocol your total energy consumption includes the solar power you use on site as well as what you import, so total kWh stays about the same. What falls is the grid electricity you buy, and the emissions that go with it. The government's SECR guidance also suggests stating how much electricity you generated yourself.

Should I use solar power or export it?

For your carbon figures, use it on site. Each kWh you use replaces a grid kWh you would otherwise buy, while exported power earns a Smart Export Guarantee tariff and doesn't reduce your gross Scope 2.

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