Some of the world’s biggest fossil-fuel producers are calling on taxpayers to help them kick their pollution habit.

The world’s biggest oil, natural gas and mining companies are stepping up their campaign to deploy carbon capture and storage, or CCS, as way to slow global warming. But with a potential $90-billion-a-year price tag, it’s too rich for them to do it on their own.

The technology siphons pollution away from the chimneys of industrial plants and injects it permanently underground. It holds the promise of reducing greenhouse gases without overhauling the world’s energy system. For all its potential, CCS raises unpalatable questions for policymakers about how to fund it, and nobody in the industry has worked out a solution beyond either direct subsidies or much higher carbon taxes. Either of those measures would make burning fossil fuels much less economical.

Even so, companies including the mining giants Glencore Plc and BHP Billiton Ltd. as well as oil majors Royal Dutch Shell Plc and Total SA have been emboldened in their push by a United Nations report showing CCS is critical to containing global warming.

“It’s about changing the way people look at CCS from thinking that it’s kind of inevitable but impossible and turning into kind of necessary and doable,” Fiona Wild, head of climate change and sustainability at BHP Billiton, said in an interview in Edinburgh. “We need to get policy regimes in place that support development over the longer term because we need scale.”

The CCS industry’s lobby group on Tuesday  released a report outlining the benefits of the technology and backers ranging from a polar explorer to the former Republican U.S. Senator John Warner. The paper from the Global CCS Institute is meant to draw attention to the issue at the UN climate talks in Katowice, Poland, on Tuesday.

Cost is the biggest impediment to CCS. The International Energy Agency estimates the price for sequestering carbon starts at about $40 a ton, double the cost of emissions in Europe. Industry needs to capture 2.3 billion tons a year by 2040. That suggests CCS would need $92 billion a year in support to work at scale—more than the entire coal industry took in investment last year.

Those figures leave CCS vulnerable both to challenges from environmentalists, who dislike the principle of helping fossil fuels, and from developers of renewables, who increasingly are building wind and solar farms at a cost rivaling traditional forms of energy.

“CCS is a get-out-of-jail card and a great business opportunity,” said Michael Liebreich, founder of the Bloomberg NEF research group in London now owned by Bloomberg LP. “Not only would it allow them to keep on doing what they do, but also it offers the prospect of being paid to clean up their own pollution. I just can’t see it ever happening at scale.”