It follows the successful completion of a five project pilot scheme, launched with Good Energy in 2013, as the Trust strives to meet its target of sourcing 50 percent of its energy from renewable sources by 2020.
The Trust hopes the investment will save up to £4m a year on energy costs, and generate an additional source of income to plough into funding conservation work.
New projects will include:
-A 2ookW water source heat pump at the Blickling Estate, Norfolk
-Two biomass boilers at Upton House, Warwickshire
-A 250kW hydro scheme at Hayeswater, Cumbria
Patrick Begg, rural enterprise director at the National Trust, said: “We have a responsibility to look after the special places in our care, requiring us to make long term decisions that will protect them for future generations.
“Many of the properties in our care are energy intensive and in remote areas without access to mains gas. The success we have seen in decommissioning oil tanks, lowering our energy costs and reducing carbon emissions has shown us that renewables play a vital part in us reaching our 2020 energy targets and in delivering more for our core conservation mission.”