The new units may be equipped to store carbon dioxide underground

E.ON's scheme will be the first such power station to be built in the UK for more than 20 years and campaigners have said it would be a step backwards.

Greenpeace wants it rejected, fearing a widespread return to the use of coal and an increase in carbon emissions.

E.ON said efficiency improvements would make it more environmentally friendly.

Spokeswoman Emily Higmore said the power station would see an increased efficiency of about 10%.

Coal-fired power stations should not have a future Douglas Parr, Greenpeace

"What that actually means is a reduction in carbon emissions of around two million tonnes - that is equivalent to taking half a million cars of the UK's roads each and every year."

But Douglas Parr, from Greenpeace, argued the plant would continue to emit large quantities of carbon dioxide "at a time when we know this is linked to climate change".

"In our view that means that coal-fired power stations should not have a future," he said.