The energy giant said it will install charge points in homes and businesses across the country, including domestic driveways and garages and office car parks.
Customers will pay from around £1,000 to have a charge point installed, while solar panels start from around £9,000.
Phil Bentley, managing director of British Gas, said: “From today, Britons can drive an electric car powered by solar energy.
“We want our customers to use greener and cheaper energy. Partnering with Nissan on powering their electric cars is a very exciting driver of growth for British Gas as electric vehicles move into the mainstream.”
Paul Willcox, managing director of Nissan Motor (GB), said: “The Nissan Leaf is pioneering the electric car revolution in the UK. Leaf drivers will be ‘filling up’ with cheaper, cleaner fuel.”