The coal industry has been making a big case for capturing CO2 for some time as part of the industry's 'Clean Coal' image makeover. It's been more promised than realized - until now. Catherine Brahic via New Scientist reports Canada's Boundary Dam power plant in Saskatchewan, Canada's largest, will be capturing CO2 before it can go up the flue and into the atmosphere. The captured CO2 will then be injected into the ground, in part to boost oil recovery.
Each year, Unit 3 of SaskPower's Boundary Dam plant emits 1.1 million tonnes of carbon dioxide. But from this summer, 90 per cent of that CO2 will never see the light of day. Instead, the gas will be piped to the nearby Weyburn oilfield and Deadwater saline aquifer, and pumped several kilometres underground.Given that the world is not going to stop burning coal any time soon, this is good news. Anything that reduces CO2 emissions is to be encouraged. This is a pilot project, and it will be getting a lot of attention. Like it or not, there are many new coal plants slated for construction around the world. Coal-fired electric power generation is a major source of greenhouse gases.
"The resulting 110 megawatts of power produced will be some of the world's most environmentally clean power from fossil fuels," says SaskPower's Robert Watson.
"2014 is a pivotal year for CCS," says Stuart Haszeldine of the University of Edinburgh, UK. "The technology is going from zero to something. It's terrific."
Carbon Capture and Sequestration (CCS) not a magic bullet, however, as the New Scientist article points out.
Boundary Dam is CCS's first big success story, and more must follow. The International Energy Agency (IEA) says that, to have a 50 per cent chance of avoiding 2 °C of global warming, which is probably too dangerous to adapt to, the energy sector can only emit 884 gigatonnes of CO2 between 2013 and 2050 (Redrawing the Climate-Energy Map, 2013). Burning proven reserves of coal, oil and gas would release 2860 Gt. So we must leave two-thirds in the ground (Technology Roadmap: Carbon Capture and Storage, 2013).emphasis added
Here's the rub: the IEA says we will build enough power plants by 2020 to burn our budget by 2050. "Climate change mitigation can and should start by lowering consumption and increasing energy efficiency," says Ruben Juanes of the Massachusetts Institute of Technology. "But the reality is that fossil fuels will continue to dominate the world's primary power for decades to come."
Following the money is important as well.
The big hurdle for CCS is money. Adding chemical scrubbers to a power station uses about 20 per cent of its power output. Power companies are unlikely to pay that hefty cost without incentives.A few caveats that should be considered. 90% capture is far better than no capture at all, but if this makes zero carbon energy sources less competitive and drives them out of the market, that's not good. It remains to be seen how efficient the capture process will be in actual production too, and what other complications follow from it. (How long does the capture solvent last, what does disposing of it entail, etc.) The loss in efficiency from the capture process means that much more coal will need to be burned to make up the difference.
For now the cost of electricity from a CCS power plant is higher than normal fossil fuels but close to wind energy, says Haszeldine. The most pricey bit is reheating the solvent to release captured CO2. Researchers are now looking into scrubbing reactions that use less energy. If that works, power plants could use residual heat alone to drive the reaction.
Can this process be adapted to existing plants, or is it more effective to incorporate it into new construction. If it does spur new construction, each new plant extends the use of coal for the lifetime of that plant. What about natural gas? The rush to obtain natural gas by fracking and convert coal plants to burning it because of price and emission advantages is well underway. So here's a question: can the same capture technology be adapted to plants burning natural gas? If so, will it increase the pressure to expand fracking?
Further, there's the time factor. It's going to take years to prove the capture technology and make it something other than experimental. Do we have that time? If we adopt it around the world, is there going to be enough capacity to store all that CO2?
CO2 is not the only problem with coal, though it is a huge one. Extracting coal from the ground, processing it, transporting it, the ash residue from burning it - all of these things impose non-trivial burdens on the planet. If carbon capture and sequestration (CCS) makes it possible to burn coal for power with lessened effects on Global Warming and Climate Change, we will still be stuck with those other environmental costs.
In an ideal world, we should be insisting that if CCS technology is available and works, it should be used as widely as possible. BUT… only as long as it takes to phase out burning coal and other fossil fuels. In the world we have, let's take the good news with a grain of salt and remember we still have along way to go.