One of the UK's largest installations of photovoltaic (PV) cells on a historic building has been fitted to the roof of the National Trust's carriage museum at Arlington Court near Barnstaple in Devon.

The 113m2 installation is expected to generate up to 6.3MWh of energy each year, saving the museum approximately £600 pounds off its electricity bill. The museum will also generate an additional income of around £2,270 pounds per year by feeding excess energy back into the national grid.

The project has been funded by sales of National Trust Green Energy, which is supplied by the charity's energy partner, npower, and raises money to support low and zero carbon energy savings projects at Trust properties.

So far 25 National Trust properties have benefited from the partnership with npower with solar panels biomass boilers and ground source heat pumps helping generate energy and save money on fuel bills, as the Trust works towards its commitment to cut its overall energy demand by 20% by 2020 and to switch to renewable energy.

The completion of the work comes at the same time as the Trust and npower announce the extension of their partnership for another two years.

npower spokesperson Matthew Cole said, “It's great that customers who choose National Trust Green Energy are getting to see these big investments in renewable energy technologies at their favourite Trust places. The new agreement means more customers can get green electricity and we'll be able to improve the carbon footprint of more Trust properties.”