Proponents say driving up the cost of coal generation will push utilities to seek out cleaner alternatives.

FORBES: Frack Gas Not Likely To Displace King Coal, Study Suggests

Cancelling such extensions will thus both push up electricity prices and, as coal, gas and oil use increases, result in an overall rise in CO2 emissions - at least in the short-run.

BBC: Will Japanese crisis curb the rise of nuclear power?

Wind farms are being planned as part of the UK and Welsh governments' push to produce more electricity from less polluting sources, and reduce the use of coal, oil and gas.

BBC: Mid Wales