Maidenhead Synagogue has installed solar panels on its roof - the first shul in the country to do so, it claims.
"The main motive was fulfilling Jewish teachings about preserving the environment and a desire to play a part in the fight for sustainability," minister Rabbi Jonathan Romain said. "The panels also serve as a powerful message to congregants about Jewish eco-values.
"If it leads to all 800 of our households installing their own solar panels, it will have a massive knock-on effect."
A combination of grants, donations and fuel bill savings are recouping the £20,000 cost. The synagogue not only generates its own electricity but sells its excess to the national grid, earning £1,500 annually. Former Maidenhead chair Danny Allen and energy specialist Ellen Salazar led the project.
The shul's self-sufficiency extends to a vegetable garden, growing tomatoes, cucumbers, potatoes, lettuce, carrots and onions.
Produce is used both at the Shabbat kiddush and for the weekly lunches for the homeless the synagogues organises.
There is also a wormery for decomposting wastage.