Plas Newydd mansion powered by sea energy

Visitors walking in the garden at Plas Newydd, Anglesey, Wales
Plas Newydd is one of five pilot projects in our good energy programme National Trust Images/Arnhel de Serra

We’ve built Britain’s biggest marine source heat pump, which will heat a 300-year-old mansion at Plas Newydd on the North Wales coast. This is the first project in the pilot phase of our Renewable Energy Investment Programme. We’ve partnered with Good Energy for this £3.5 million pilot scheme which will help us reach our renewable energy targets.

Swapping oil fuel for sea energy
The marine source heat pump will provide 100 per cent of the heating needed by Plas Newydd Country House and Gardens. The 18th-century mansion used to be our biggest oil user and on some winter days would consume 1,500 litres of oil a day – the same as a typical house would use in ten months.
Now Plas Newydd will be heated with a new local and clean energy system, which 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 300kW marine source heat pump cost £600,000 to install in total and is expected to save us around £40,000 a year in operating costs. That money can be reinvested back into the conservation of this elegant mansion.
Challenges and champions
Adam Ellis-Jones, our Assistant Director for operations in Wales, said: 'With the Irish Sea right on the doorstep of Plas Newydd, a marine source heat pump is the best option for us. However, there are very few marine source heat pumps and none of this size in the UK, so it has been a challenging project but a very exciting one.’
Juliet Davenport OBE, founder and CEO of Good Energy, said: 'This project shows that cutting-edge British renewable technology can transform the energy use of some our oldest buildings.’
If pilot projects such as Plas Newydd are successful, we plan to invest in 43 renewable schemes at the places we look after.
Patrick Begg, our Rural Enterprises Director, said: 'This is a transformative scheme. 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’s clear to us that we need to make big changes so that we can continue to protect our treasured places and tackle the impacts of climate change. This successful scheme marks a major step forwards in our clean energy journey.'
The bigger picture
Plas Newydd is just the start of our Renewable Energy Investment Programme. We have committed to reducing our energy use by 20 per cent and generating 50 per cent of our energy from renewable energy sources by 2020. This will enable us to reduce our energy costs by more than £4 million per annum, releasing more money for our important conservation work across England, Wales and Northern Ireland.