Work has started on installing Europe's biggest floating solar farm.
About 12,000 panels will be placed on a reservoir in Greater Manchester as part of efforts to reduce energy costs, water firm United Utilities said.
The £3.5m project - due to start operation by Christmas - would keep "future water bills low", it added.
The 45,500 sq-m (484 sq-ft) array will be the second biggest floating solar farm in the world, after a scheme in Japan, a company spokesman said.
Chris Stubbs, the firm's head of renewable energy, said the project at Godley Reservoir in Hyde would provide the local water treatment works with about 33% of its energy.
He added it would also help the company reach their target to generate 35% of their in-house power needs via renewable sources.
"While floating solar has been deployed elsewhere, most notably in Japan, it is a new technology to the UK."
It follows the opening of the UK's first floating solar panel project, involving 800 panels, in Berkshire last October.
In the summer, the UK government said it planned to close or significantly reduce subsidies for many new solar farms before 2016.
A United Utilities spokesman said the firm was also considering setting up another floating solar farm in Lancaster after this year.