Plans for solar farms of up to 10,000 panels on two sites in Carmarthenshire have been approved.
The development on Ffos Las horse racing course and the former Cynheidre Colliery near Five Roads could power up to 1,000 homes.
Councillors approved the planning application on Thursday.
Made up of rows and rows of individual ultra solar panels, the electricity generated will be fed into the National Grid.
In January neighbouring Pembrokeshire become the first council in Wales to approve a solar farm when planning grant permission was granted for land at Rhos-Y-Gilwen Mansion, a country retreat near Cardigan.
Entec, acting as an agent for developers, said the two sites in Carmarthenshire had been chosen as they were well positioned and well screened from surrounding areas.
To encourage low carbon electricity generation schemes to feed in to the National Grid, the UK Government currently pays operators a subsidy guaranteed for 25 years.
But due to the number of applications it said it planned to "tweak" the system next year.
Energy Secretary Chris Huhne said big solar farms threatened to use up the available cash for homes and small businesses who want to use the system.
BBC Wales Online - Thursday, 3 March, 2011.
