Passing carbon dioxide through slag left over from steel-making turns the waste product into a strong material that can be used for construction. Pumped into greenhouses, it provides a growing boost for crops. Put into tanks of algae, it can be used to make biofuels. Waste carbon dioxide can even be cleaned up to “food grade” and injected into fizzy drinks.
But these processes are rare — instead, carbon dioxide from power generation is normally simply vented into the atmosphere, where it contributes to global warming. When the gas is needed for an industrial process, it is manufactured from scratch.
Peter Styring, a professor at the University of Sheffield, northern England, wants to change this situation. He believes that carbon capture and utilisation (CCU) could be one of the best ways of combating climate change, by turning carbon dioxide from a waste gas into an integral part of industrial processes.
Projects
“There are real possibilities here that we are still only at the beginning of exploring,” he said. “Some of the technology we need has already been developed, some is at an early stage, and in some cases we need to develop new chemistry.”
There are a few examples of the development of processes to use CO{-2} like this. The U.S. is spending $1bn on CCU research, including a project at Sandia Laboratories to make synthetic diesel from carbon dioxide, and the German government is putting €118m into a project with Bayer called the Dream production plan. In Australia, work is under way to manufacture cement using the carbon dioxide from power plants, and in several places around the world, algae is being cultivated that would absorb the gas and could itself then be used to make biofuels.
Report
But in the U.K., by contrast, the government is pouring at least £1bn into carbon capture and storage technology — where the carbon from power stations is liquefied and stored in depleted oilfields under the North Sea — but nothing into recycling carbon dioxide.
Styring is confident that many of the potential uses for carbon dioxide could make economic sense, with the right investment. In a report he co-authored, entitled Carbon Capture and Utilisation in the Green Economy, published by the Centre for Low Carbon Futures, he points to a case study by Newcastle University. There, a group of researchers have developed a new class of catalysts for the conversion of CO{-2} into commercially important cyclic carbonates, which can be used as electrolytes for lithium ion batteries; additives for petrol, diesel and aviation fuel; solvents; and in the production of polycarbonates and polyurethanes, and other commercial chemical processes.
The group calculated that a plant operating this system could have a payback time of less than two years and generate profits of more £1.4bn over 15 years, if the resulting carbonates were sold at current market prices.
Many of the processes envisaged for CCU require some energy input — but the report's authors note that this could be provided by renewable energy, especially when wind or solar plants are producing energy at times of low demand. In this way, producing fuels from CO{-2} could effectively be a way of storing renewable energy in another form.
However, the costs are still high for many of the potential applications of waste CO{-2} — about 10 times too expensive in the case of algae, for example. Much more investment is needed to bring down the costs, and putting a sizeable price on carbon dioxide emissions would also help.
Styring said: “The U.K. government needs to invest in R&D for carbon capture and utilisation and investors need to be made aware of the potential benefits of the technology so that barriers can be brought down. Our report shows that all CCU options could be relevant to the U.K. and given its business-oriented academic community, the U.K. could benefit from the commercialisation of the technologies involved.” — © Guardian Newspapers Limited, 2011
