Three applications to test drill for gas have been approved by Vale of Glamorgan Council's planning committee.
Bridgend company Coastal Oil and Gas Ltd wants to carry out exploratory tests at three sites at Llandow, Llantrithyd, and near Dyffryn.
The test drilling could then lead to the process of hydraulic fracturing - or fracking - where water, sand and chemicals are pumped into a well to split the rock, and release gas.
Campaigners have raised fears about water contamination, and say even exploratory drilling will damage the countryside with excess noise and traffic.
Supporters say fracking could provide vital affordable energy.
Cliff Patten, Planning Consultant for Coastal Oil and Gas Ltd - whose applications to test drill for gas are being considered by Vale of Glamorgan Council this evening - says the company has drilled six boreholes in South Wales "without any major incidents."
He told our Correspondent Carole Green "this is a fairly ordinary application - hundreds of these have been drilled" throughout the UK.
Anti-fracking campaigners in the Vale Of Glamorgan are tonight demonstrating in Barry, to demand that councillors turn down plans to test drill at three sites.
The Brigend company Coastal Oil and Gas Ltd wants to carry out exploratory tests at locations including Llandow and Llantrithyd. It also has plans to test drill near Llantrisant.
The protest group Villages Against Drilling says exploratory drilling for gas will spoil the countryside, but those in favour dismiss the environmental concerns, saying test drilling is a step on the road to fracking which in turn could provide vital affordable energy.
Campaigners have protested outside the Senedd to voice their concerns against fracking in Wales.
The Welsh Government says we need to look at new ways of sourcing energy. Many of those opposed to fracking say they're concerned about the environmental consequences.
Alexandra Lodge reports.
Hundreds of campaigners are expected to gather outside the Senedd today to show their concerns against so-called 'fracking' in Wales.
'Fracking' is the term given to a technique used to release gas and oil from shale rock. It involves drilling down before fracturing layers of rock using a pressurised liquid.
Anti-fracking groups such say 'this is not an alternative energy source' and that "the money which is being in invested in ever more extremes of energy extraction should now go into clean energy'
The Welsh Government say given the challenges of the energy sector they understand there is a need to look at the potential of this type of energy resource. However, there is also a need to fully consider the impacts on communities and the environment.
Around 35 campaigners have demonstrated outside the Senedd in Cardiff Bay this afternoon, to oppose fracking in Wales.
The event was organised by Frack-Free Wales, after the Chancellor George Osborne signalled his support for the controversial method of extracting shale gas in last month's Budget.
Frack-Free Wales' plans for today's demonstration began after the Chancellor signalled the UK Government's support for fracking in last month's Budget.
– George Osborne, Chancellor, in his Budget speech
I also want Britain to tap into new sources of low cost energy like shale gas.
So I am introducing a generous new tax regime, including a shale gas field allowance, to promote early investment.
And by the summer, new planning guidance will be available alongside specific proposals to allow local communities to benefit.
Shale gas is part of the future. And we will make it happen.
Around 200 campaigners are expected to protest outside the Senedd later against so-called 'fracking' in Wales.
Hydraulic fracturing involves pumping high pressure fluids into shale rock to recover gas and oil.
Campaigners 'Frack-Free Wales' say they have "grave environmental concerns" that the methods "are unsafe to our future generations."
They are planning to hand in a letter, addressed to the First Minister Carwyn Jones.
It is thought there is a substantial amount of gas under parts of South Wales.
The most controversial fracking issue here has centred around an application to test drill for shale gas at Llandow in the Vale of Glamorgan.