FOR more than 30 years Peterhead power station has churned out electricity from a windswept spot on the north-east coast of Scotland. Its chimney (pictured) is a familiar landmark for strollers on Aberdeen’s chilly beach. Yet soon the ageing gas-fired plant could host a crucial experiment. Engineers from Shell, an oil firm, and SSE, an energy company, plan to add technology that will capture the carbon dioxide which billows from Peterhead’s furnace and store it in a depleted gasfield more than a mile beneath the North Sea. That could cut its emissions by up to 90%, making Peterhead by far the cleanest gas plant in the world.

Peterhead is one of two preferred bidders in a government contest that aims to kick-start Britain’s adoption of carbon capture and storage (CCS) technologies. The other pet project is a proposed coal-fired plant at Drax power station in Yorkshire, which will pipe its pollutants about 50 miles to the coast before trapping them in rocks beneath the waves. Yet politicians have been soliciting similar proposals since 2007, without bringing any to fruition; abortive efforts at Peterhead go back even further. Boosters hope this latest crop will buck a sorry trend.

The rewards could be great. CCS is one of a very few ways to clean up industries such as steelmaking or chemicals. Fossil-fuel power stations fitted with carbon-capturing kit would provide an unusually flexible source of green power (solar panels and wind farms work only in the right weather, and nuclear reactors cannot respond quickly to changes in demand).

These benefits would bring savings. Carbon capture could be lopping £30 billion ($51 billion) off Britain’s annual energy bill by 2050, says the Energy Technology Institute, a government and industry research body. The International Energy Agency, an intergovernmental outfit, reckons CCS will have to deliver one-sixth of the emissions cuts required to limit the damage done by climate change, and that forgoing it would raise costs by 40%.

Britain is well placed to cash in. Its wealth of underwater engineers will need new ways to keep busy as the North Sea’s fields run dry. A steady supply of carbon could be useful to roughnecks, who are experimenting with techniques that use the gas to squeeze more oil from mature wells. And the country’s deep aquifers and depleted reservoirs could probably hold 100 years-worth of emissions.

That makes slow progress all the more frustrating. In May MPs on the climate-change select committee complained that government dithering had led to a “lost decade” for CCS in Britain. Money is part of the problem—boffins say energy from the first CCS plants could cost £150-£200 per megawatt hour, four times the current wholesale price of power and more expensive even than offshore wind farms. European laws that oblige Britain to invest heavily in renewables are diverting resources away from CCS, says Judith Shapiro, an industry spokesperson.

Yet the government is digging deep to make sure its latest efforts pay off. In 2007 it put aside £1 billion to help fund the capital costs of some CCS projects—not least the huge expense of laying new pipelines overland. Lately it has also promised ongoing subsidies of the type given to renewables (at a rate to be agreed). Bosses at Peterhead and at Drax say that next year they hope to make a final decision on whether or not to press ahead.

Pessimists say that a few pilot projects will not make an industry, even if the technology proves viable. Some fret that runners-up in the government’s competition will run out of money while it mulls what subsidies to offer; others warn of bottlenecks without more efforts to identify storage sites. One big uncertainty is how the public will react when plans for carbon capture are better known. Though engineers have been cramming carbon underground for several years—notably in Norway—the idea could still spark alarm. That would not easily go back in the bottle.