More than 400 UK churches are planning to switch to renewable energy providers in a move which will see more than £1 million shifted to clean power.

Launched at the beginning of Lent by charities Christian Aid and Tearfund, The Big Church Switch invited churches and individuals in the UK to switch energy companies, to demonstrate the need for a transition from fossil fuels.

This week the charities' partner 2buy2 will negotiate with energy companies to find the best deal. Because of the number of churches and the total value of their business – more than £1 million – it can secure a better deal with green energy providers.

Among the 424 churches that have registered to switch is the oldest Methodist building in the world, The New Room in Bristol. Manager David Worthington said: "We may be the oldest Methodist building in the world but that doesn't mean we have to use the polluting energy of the past.

"We take seriously the impact we have on our neighbours, both locally and globally. Switching our energy provider to clean sources of power is a simple thing we can do to help the global transition to a low carbon world. If we, in a building as old as ours, can embrace the idea of renewable energy then anyone can."

The Bishop of Manchester, Rt Rev David Walker, welcomed the initiative, saying: "By creating technology which can turn wind and sunshine into clean and renewable energy humans continue to benefit from the gift of creation. Making the most of this bountiful harvest is a common sense way for us to roll back the ravages of climate change and ensure we are taking an active role in being part of the solution. The Big Church Switch is a practical way for us all to do our bit."

Christian Aid's head of advocacy, Laura Taylor, said: "The Big Church Switch shows that people are willing to reduce our CO₂ emissions, and that we want to take action together. The UK Government must help accelerate the shift from fossil fuels to renewables as they prepare the next carbon budget for our country."

Churches are able to sign up to the Big Church Switch throughout the year and are offered the opportunity to switch as and when their current contracts end.