More than 5,500 churches in the U.K. are using renewable energy, according to Christian Aid.
Fifteen Anglican cathedrals, including York Minster and Salisbury Cathedral, are among the religious sites now using 100 percent green electricity tariffs, the charity said Friday.
There are 16,000 Anglican churches in the U.K., although the places of worship now using renewable energy come from a range of denominations, including Catholic, Baptist, Quaker, Methodist and Salvation Army.
Christian Aid said that, based on figures provided by national church buying group 2buy2, the average annual electricity bill of a church was £1,000 ($1,300). By using renewable energy, British churches helped to divert over £5 million from fossil fuels to renewable energy providers.
"Climate change is one of the great moral challenges of our time and so it's fantastic to see churches doing their bit to ensure they reduce their impact on the environment," the Bishop of Salisbury, Nicholas Holtam, said in a statement.
"They are also giving a boost to clean energy which is essential to reduce harmful carbon emissions," Holtam, who is also the Church of England's lead bishop on the environment, added.
The switch to renewables has come via a range of initiatives. These include the Church of England's procurement group, Parish Buying, which uses the Church's bulk-buying power to get competitive rates for gas and electricity. All the electricity bought via the scheme comes from U.K.-based renewable sources.
Some religious buildings are even generating their own clean energy. In 2016, for example, 150 solar panels were installed on the top of Gloucester Cathedral. Other churches have made use of the Big Church Switch Campaign, a collaboration between Christian Aid, Tearfund and the Church of England's Environment Programme.
"Renewable energy is now a mainstream power source," Emma Pinchbeck, the executive director of RenewableUK, said.
"Any organization that takes tackling climate change seriously would want to make sure it's taking full advantage of our bountiful natural resources, including wind, wave and tidal power," she added.