The Spaans Babcock turbine will use water power to generate electricity for the park's visitor and education centre, supplying 59,000kW hours of electricity.
The trust said the centre will be the nation's most energy-efficient building. Funding is part of the overall Livinggreen project. The turbine cost £350,000 with funding from City Bridge Trust, Thames Water and the Heritage Lottery Fund.
The building, opened in November 2011, includes solar panels, an air source heat pump and a wood-burning stove.