Conventional CCS uses three basic methods: pre-combustion (removing carbon dioxide from the fuel before burning), post-combustion (capturing the CO2 in the flue gas) and oxy-fuel (more efficient combustion, using purified oxygen). …
Conventional CCS uses three basic methods: pre-combustion (removing carbon dioxide from the fuel before burning), post-combustion (capturing the CO2 in the flue gas) and oxy-fuel (more efficient combustion, using purified oxygen). The more developed countries have been pumping out increasing amounts of carbon dioxide since the dawn of the industrial age, and as well as emissions from power plants we also have a problem with emissions from transport, land use and industrial production – for example, cement factories and refineries. This all adds up to a vast amount of carbon dioxide in the atmosphere, and one proposed solution is a network of devices (like very large windmills) to suck CO2 from the air.
There are several arguments in favour of air capture, including low energy consumption. And according to a recent report by the Institution of Mechanical Engineers, based on research carried out by the University of Columbia, the cost of a UK-wide network of air capture devices (about 100,000 units) would be about US$2 billion and cover an area of only six square kilometres.
Professor Brandani vigorously questions these figures, citing a number of problems including humidity (the tests were carried out in the New Mexican desert, not humid or cold, damp climates like Scotland), planning regulations and production costs. He believes it would cost 10 times more than “conventional” CCS and consume two to three times more energy. It would also require infrastructure to transport and store the carbon dioxide it “scrubs” from the air, says Brandani, which would add even more to the cost.
“It is not difficult to produce air with very low CO2 content,” adds Brandani, citing examples like submarines and spacecraft. “The difficult part is to concentrate the CO2 – which is technically feasible but also expensive, needs considerable amounts of energy and requires incentives and legislation.”