Plans have been revealed to upgrade a wind farm in a village near Sunderland.
E.ON UK wants to pull down the existing four turbines built in 1997 at Great Eppleton, Hetton-le-Hole, in order to boost capacity.
It plans to replace the existing 71m (232ft) high twin-bladed machines with more up-to-date turbines, which will be 115m (377ft) high.
A planning application submitted to Sunderland City Council will be considered soon.
An E.ON UK spokesman said that, if approved, the new turbines could quadruple the capacity of the scheme.
It has also agreed to sponsor a project to aid the recovery of water voles in the area.
Darren Cuming, project developer for E.ON UK, added: "The turbine design at Great Eppleton is very unusual for the UK in that they have two blades rather than three.
"They're also not very powerful when compared to a modern turbine and so we're looking to take the old ones out and replace them with much more powerful ones.
"Those new machines could both produce enough electricity for more than 5,000 homes and displace the emission of 21,000 tonnes of carbon dioxide every year."