It costs the gas and electricity customers £84 per year more than the firm's standard dual fuel deal.
"Green tariffs are moving from niche to mainstream products and we're leading the industry by offering a tariff that will do more for the environment than any other product currently available," Gearoid Lane, managing director of British Gas new energy, said.
The company has also launched a second electricity-only tariff which carries an average £20 premium on the cost of annual electricity usage.
"We welcome the efforts of companies such as British Gas in making inroads into the area of green tariffs," Energy Saving Trust chief executive Philip Sellwood told 24dash.com.
"Our research shows that over one third of all households are interested in signing up to a green tariff, once the concept had been explained to them.
"We need to make sure they get the best impartial advice to make informed choices."
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