Hayes replaced fellow Conservative Charles Hendry, who was demoted to the backbenches, earlier this month. Hendry had been responsible for renewable energy as junior minister since the coalition government was elected in 2010.
The appointment of Hayes prompted observers to comment the Conservatives were toughening up their approach to renewable energy in terms of spending.
In 2009, Hayes was quoted by the BBC saying that wind power failed to pass twin tests for economic sustainability and the environment.
A spokesman for the Department of Energy and Climate Change (DECC) said: "The secretary of state has been here six months, got his feet under the table, and now is the opportunity to spread the workload fully between all four ministers in the new ministerial line up – for instance, him having a role in renewables while John Hayes sees the Energy Bill through."
There have been reports of friction between Davey and chancellor George Osborne over possible cuts to onshore wind subsidies of 25%. In the event, Davey kept the cut to 10%.
UK energy minister Davey assumes control of renewables
UK: UK energy minister and Liberal Democrat Ed Davey has assumed responsibility for renewable energy from newly appointed Conservative junior minister John Hayes.
