The National Trust in the UK, founded in 1895 by three fascinating people who worked on social reform in industrial England, looks after more than 500 historic houses and castles in England, Wales and Northern Ireland. It also cares for more than 250,000 hectares of land and more than 780 miles of coastline; and nearly a million works of art.
And, while many of its magnificent buildings are drafty, and built long before energy efficiency became commonplace, the National Trust has been introducing climate friendly strategies that will save energy and money and move towards generating more of its power from renewable sources.
On the North Wales coast, where they care for a 300-year-old mansion, they installed Britain’s biggest marine source heat pump to provide 100 per cent of the heating needed by Plas Newydd Country House and Gardens.

National Trust
During the Regency years in England, Lady Eleanor Butler and Miss Sarah Ponsonby received a stream of visitors to their little cottage which, over the years, they transformed into a Gothic fantasy of projecting stained glass and elaborately carved oak. The poet William Wordsworth, Sir Walter Scott and the Duke of Wellington had tea there, as visitors can do today.
The 18th-century mansion used to be the Trust’s biggest oil user and on some winter days, consumed 1,500 litres of oil a day – the same as a typical house would use in ten months. Before installing the marine pump in 2014, the Trust spent five years reducing the house’s energy demand.
The 300kW marine pump cost £600,000 to install and after some initial teething problems, is saving around £30,000 a year in operating costs. It pumps a small amount of sea water from the Menai Strait in Anglesey, through pipes to and from a heat exchanger on the shore, and then up 30 metres of cliff face to the mansion’s boiler house. The installation was done by Kimpton Energy Solutions.
It was a challenging project because there are few marine source heat pumps in the UK and none of that size, says Adam Ellis-Jones, Assistant Director for operations in Wales.
The Trust has plans to invest in 43 renewable schemes at places it looks after. ‘This is a transformative scheme,” says Patrick Begg, the Rural Enterprises Director. “I couldn’t be more delighted that Plas Newydd – a really sensitive and special place – is not only converting to clean energy, but taking the lead on innovation.’
“it was one of the catalyst projects that allowed the Trust to see the impact renewables could have both financially and with our environmental impact,” said Paul Southall in 2018. “It started us on a course over the following years of investing over £30 million in renewable energy projects.”