Cutting Carbon: Should We Capture and Store It?
In the push to cut the amount of carbon we release into the atmosphere, solutions usually focus on how to reduce our power use (drive less, insulate our houses better) or how to replace our carbon fuels (coal, oil) with renewable sources (solar, wind, biofuels).
But even in the most optimistic scenario, we will be using fossil fuels such as coal for years to come. China and India aren't going to suddenly shut down all their new coal power plants, nor will Western industrial giants close their factories overnight. Solar and wind may be today's sexy new energy sources, but coal is the fastest-growing fuel in the world, boasting twice the known gas reserves and three times the known oil reserves. "Coal is here to stay," Milton Catelin, head of the World Coal Institute, told the World Future Energy Summit in Abu Dhabi on Jan 19.
That's why governments and industry have recently begun to pay more attention to carbon capture and storage (CCS) — a process that traps CO2 produced by factories and gas or coal power stations and then stores it, usually underground.
The potential impact of CCS is huge. The Intergovernmental Panel on Climate Change says CCS could contribute between 10% and 55% of the cumulative worldwide carbon-mitigation effort over the next 90 years. The International Energy Agency says CCS is "the most important single new technology for CO2 savings" in power generation and industry, and will need to account for about one-fifth of the carbon-mitigation effort this century — reducing carbon emissions as much as renewable energy sources will.
Though it requires up to 40% more energy to run a CCS coal power plant than a regular coal plant, CCS could potentially capture about 90% of all the carbon emitted by the plant. To solve the problem of climate change, we "need to use every option we can," says Nick Otter, head of the newly created Global Carbon Capture and Storage Institute (GCCSI) in Australia, which will fund pilot programs and network CCS efforts around the world. "And we've got to have some realism to the approach."
Like most technologies, CCS was developed as a way to make money. Oil companies started injecting CO2 into underground oil-bearing strata in the U.S. in the 1970s. The technique — known as enhanced oil recovery — allowed them to extract up to two-thirds more oil than by simply pumping the fuel to the surface.
The first country to store CO2 underground deliberately to keep it out of the atmosphere was Norway. When the government there introduced a carbon tax in the early 1990s, energy giant Statoil began capturing the CO2 from its Sleipner natural-gas platform in the North Sea and pumping it into a saline-filled sandstone layer under the seabed. Since 1996, the operation has cut Norway's CO2 emissions by almost a million tons a year, or about 3% of the country's 1990 CO2 emissions. Other projects have followed, including one on the U.S.-Canada border that has been pumping CO2 from a coal plant into an oil reservoir for the past decade.
The question is whether the technology can be scaled up and used on power plants everywhere. In the past couple of years, governments in Australia, Canada, China, Europe, Japan and the U.S. have begun investing in small-scale pilot projects to figure out the best way to take CO2 out of power-plant emissions and store it underground. The European Union has set aside $1.5 billion to build seven CCS pilot projects; Washington has promised millions of dollars for trials and a large-scale CCS power plant; and the Australian government is spending almost $100 million a year on the GCCSI. Last year the world's first CCS coal plant opened in Germany. Though it's small, the operation captures some 240 tons of CO2 a day and trucks it to an empty gas field where it is injected into an underground aquifer.
Not everybody supports the rush to CCS. To the frustration of Western governments and industry leaders, Brazil has consistently blocked the inclusion of CCS in the Kyoto Protocol's Clean Development Mechanism, which allows rich countries to meet reduction targets by investing in green plants and technology in the developing world. Analysts believe that Brazil doesn't want money diverted to CCS from avoided deforestation projects, from which the country benefits, though Brazilian oil giant Petrobras is a keen backer of carbon capture.
Critics say large-scale CCS deployment is decades away and that the world is better off focusing on renewable energy. Some environmental groups say that, just like nuclear-power stations, CCS technology leaves behind a dangerous waste material that has to be stored. Greenpeace says there's no way of knowing that carbon will stay underground for centuries and has called CCS "unproven, risky and expensive." Opponents to CCS point to an infamous natural disaster in Cameroon in 1986. Perhaps triggered by a landslide, a crater lake called Nyos emitted a large cloud of CO2 that suffocated 1,700 people. Could storing carbon set us up for future disasters?
It's unlikely, say an increasing number of industry figures who want governments to embrace CCS as the most pragmatic response to climate change. Bjorn Berger, a research adviser to Norway's Statoil, says using CCS is a no-brainer. "It has been staying where we put it," he says of the carbon there. "We study it very carefully and know exactly what it does. If we get realistic about the fact that we need the fossil fuels in the development of places like China and India, then this is a way to make that acceptable." Otter, CEO of the GCCSI, says, "The only way to understand CCS is to actually do it." Addressing the energy summit, he urged governments to move quickly. "We cannot do without this, in my view. We're looking for really positive and quick action ... Deployment is what we're talking about. Not research."