A wind farm big enough to power 240,000 homes will be built near Dalby by 2020, the Queensland government has decided.

In state Parliament on Thursday, State Development Minister Anthony Lynham announced the environmental impact study for the $500 million Coopers Gap wind farm proposed by AGL Energy had been approved by the Co-ordinator-General.

A new wind farm near Dalby is set to generate 350 jobs during construction.

"AGL has advised it will employ local people and use local contractors from across the Wide Bay Burnett and Darling Downs wherever possible," Dr Lynham said.

"This project will contribute up to $4 million each year to the local economy."