Rooftop solar, grid connection and VAT: 5 questions answered
G98 vs G99, telling your network operator, MCS installers and the 0% VAT rate on solar installations in the UK.
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What is the difference between G98 and G99?
They are the two main network connection routes in Great Britain. G98 covers small type-tested generators up to 16 amps per phase, which is about 3.68 kW on a single-phase supply: you connect and then notify your network operator, normally within 28 days. G99 applies above that level and needs the operator's permission before you install.
Do I have to tell my network operator about rooftop solar?
Yes. Your installer normally does this for you: a G98 Form B within 28 days of installation for small systems, or a G99 application before installing for larger ones. Batteries count too. Ask your installer for a copy of the notification and keep it with your paperwork.
That depends on what you want from the system. The Energy Saving Trust says most energy suppliers require a valid MCS certificate before they will pay you under the Smart Export Guarantee. If you want export payments, check with your chosen supplier what proof it needs before you sign an installation contract.
For most homes, installation is currently zero-rated. A 0% VAT rate applies to the installation of energy-saving materials, including solar panels, in residential accommodation in Great Britain from 1 April 2022 and in Northern Ireland from 1 May 2023, until 31 March 2027. The reduced 5% rate is scheduled to return after that unless the government extends the relief. The relief is tied to installation, not to materials alone.
Is VAT charged on a plug-in solar kit I fit myself?
That is not settled by the rules we can point to. The 0% rate is tied to installation of energy-saving materials by a contractor, and materials-only sales are treated differently. Whether it applies to a kit you fit yourself depends on how the retailer supplies it, so check the VAT shown on your receipt and HMRC's Notice 708/6.
