Making the best of coal and CO2

Prof Peter Edwards – a pragmatic use for power station emissions
High-profile academics are sometimes accused of focussing too heavily on glamorous areas of scientific research which carry the prospect of fame and fortune (or big funding, at least). This certainly can’t be said of Prof Peter Edwards FRS, Head of Inorganic Chemistry at the University of Oxford, who came to BRLSI to explain his very down-to-earth perspective on feeding our energy needs in the next few decades, in a Science Group lecture entitled (rather enticingly) Turning CO2 into Fuel.
Prof Edwards began with a brief survey of renewable energy prospects which concluded that, like it or not, the world is going to be using coal and other hydrocarbons for quite a long time to come, especially in the “developing” world (which, as he pointed out, is actually quite developed already). This is because hydrocarbons are, quite simply, the best in terms of supply, storage and transportation, and as such the only current energy source which can be guaranteed to meet our needs. The problem, of course, is emissions, and in particular everyone’s favourite greenhouse gas, CO2, a storage/disposal problem to which, in Prof Edwards’ view, we still don’t have a conclusive answer.
It’s at this point that Prof Edwards is injecting a hefty dose of pragmatism (and an even heftier dose of science) into the energy debate, with plans to use CO2 to help convert methane gas (eventually) into denser liquid fuels suitable for use in transport and other applications where hydrocarbons currently rule. It’s “eventually” because the process involves multiple stages, beginning with converting the ultra-stable CO2 into CO (the poisonous but highly reactive Carbon Monoxide), and then combining it with a catalyst and methane to produce ‘syngas’, which can in turn be converted into liquid fuel.
Prof Edwards was scrupulous in pointing out that this isn’t a free source of energy – we’ll still need power from somewhere to drive this complex chain of chemical processes. So what’s the point? Basically it’s a way of liquefying hydrogen at ambient temperatures (thus making it easy to store and transport), which as we’ve heard at BRLSI before, is one of the great energy goals being pursued today.
The real key to its value, however, lies in the flues (chimneys) of coal-fired power stations, from which Prof Edwards hopes we’ll be able to extract the CO2 in a process that will see liquid fuel, as well as electricity, flowing from the power station gates. As he put it, the world is going to have a lot of these stations in the coming century, and we may as well make the best of them.
One encouraging aspect of all this, Prof Edwards told us, is that China and other developing nations, by far the biggest builders of new coal-fired power stations, are highly aware of emission problems and very keen to develop this kind of technology. As the Head of the Catalyst Laboratory in Poona, India, told him, “we’ve got biomethane coming out of our ears here”. One day it may be powering our cars.

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