The chairman of the Environment Agency, Lord Smith, is expected to give his support to the expansion of the controversial "fracking" method of extracting natural gas from shale rock in the UK.
Energy companies say the use of fracking will lead to cheaper supplies.
But critics say there are risks from the process, which has been linked to two earth tremors in Lancashire.
Lord Smith is also expected to give his backing to nuclear power.
The process of fracking (fracturing) involves pumping water and chemicals into shale rock at high pressure to extract gas.
There has been a boom in the process worldwide, as nations seek new and less expensive ways to increase their energy supplies.
But fracking has been blamed for the pollution of underground and surface water supplies, as well as causing minor earthquakes.
The BBC understands that Lord Smith is to say he will not stand in the way of fracking in the UK.
The former Labour cabinet minister will admit that it causes environmental risks, but with careful monitoring these may be overcome.
Lord Smith is expected to insist, however, that power firms should be required to capture the carbon emissions from burning gas and store them in underground rocks to prevent them contributing to climate change - something power firms are not currently obliged to do.
The BBC's environment analyst, Roger Harrabin, says Lord Smith is also likely to anger environmentalists by calling for more nuclear power stations in the UK.
