That depends on your lifestyle and what you use electricity for. If you use gas for heating and hot water and are out all day you may only use about 30%, averaged over the year. You can increase this by using devices like a washing machine on a sunny day if possible, or if you have an electric vehicle that you plug in during the day. If you use gas for heating hot water you can fairly easily divert excess electricity to do some of this. You can improve it even further by using a battery to store excess electricity generated (see section on ‘Electrical battery storage and other complementary technologies’ below).