FINAL preparations to rebuild two polluting "carbon dinosaurs" as Europe's largest clean-coal power stations were launched by ScottishPower yesterday.
The planned 1 billion project would cut carbon dioxide emissions at the plants at Longannet in Fife and Cockenzie in East Lothian by 20 per cent.
It could also pave the way for reducing such emissions by 90 per cent by pumping them underground when "carbon capture" technology is advanced over the next decade.
Environmental groups welcomed the announcement of a 6 million feasibility study into the clean-coal plans, but said it must be coupled with carbon capture being developed.
WWF Scotland warned ScottishPower that otherwise "we will not have done anything like enough".
Friends of the Earth Scotland (FoES), which has campaigned for the two plants to be cleaned up or shut down, said it was a step in the right direction. They have topped the group's UK-wide pollution league table since 2003.
ScottishPower said if the project went ahead, work to create completely new power stations within the existing buildings could start in 2009, with electricity being generated from 2012.
It would involve installing new "supercritical" turbines and boilers which would burn coal at ultra-high temperatures and pressure to reduce emissions.
ScottishPower said the rebuilt stations could have a lifespan of 35-40 years - far beyond the expected 12-year life of Longannet when the installation of equipment to cut sulphur emissions is completed next year.
Alstom Power and Doosan Babcock are designing the clean-coal equipment for what would be the largest project of its kind in Europe. The feasibility study, to be completed by the end of next year, follows three years of preparation work.
Carbon capture would involve pumping carbon emissions from Longannet into disused underground coal seams to drive out methane gas, which could then be used as a fuel. The carbon emissions would remain trapped in the coal seams.
The plants provide about one-quarter of Scotland's electricity, with much of the rest coming from nuclear.
Duncan McLaren, the chief executive of Friends of the Earth Scotland, said: "Coal remains a dirty and polluting fuel. Refitting with supercritical boilers should cut emissions by about 20 per cent, but this still leaves 80 per cent of the climate-changing pollution unaffected.
"Even after this refit, these power stations will be dirtier than gas turbines, so it is essential that ScottishPower move swiftly to install carbon capture and storage technology in addition."
Alex Salmond, the First Minister, who visited Longannet yesterday, said ScottishPower's clean-coal plans would reduce Scotland's carbon dioxide emissions by 5 per cent, and carbon capture by as much as 25 per cent. He said: "This technology provides huge opportunities to reduce climate change."
Ignacio Galn, the chairman and chief executive of Iberdrola, ScottishPower's Spanish owner, said: "We are delighted today's announcement puts ScottishPower on track to deliver a revolutionary change in low carbon energy generation in Scotland."
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CLEAN coal technology involves a different generation process. Instead of changing the fuel, lower carbon dioxide emissions from power stations are achieved by burning coal at much higher pressure than at present, and at a temperature of 600C.
The high pressure and temperature increases the plant's efficiency so more electricity is generated from less coal.
The "supercritical" boiler involved is smaller than current boilers, but the amount of water used is the same.
Carbon dioxide capture and storage involves separating from the flue gas stream and pumping it into storage areas, such as underground mines.