Carbon trap

From Mark Barrett You report that carbon capture and storage (CCS) will soon be carried out on a commercial scale at a Canadian power plant  (8 March, p 8), but the technique’s own footprint should not be overlooked. CCS increases the fuel needed  to produce a unit of electricity by 15 to 40 per cent, and therefore the amount of carbon dioxide churned out per unit of power. By increasing fuel use, it reduces a country’s energy security and increases impacts of extraction. Applying CCS in a gas-fired plant means we will have less gas available to replace coal, and therefore may well increase our total CO2 output, since gas is greener than coal. Then there’s the issue of potential leakage of the stored carbon. With what confidence can we predict what will happen over the coming centuries? Is this the same level of confidence that we apply to secure underground nuclear waste dumps? CCS will augment our fossil-fuel power generation and reduce more worthwhile efforts to improve the energy efficiency of buildings, industry and transport, for example. Global investment in these proven, safe options is how societies can be supported sustainably and indefinitely. Colchester, Essex, UK
From Philip Roberts A better option than CCS would  be to invest in refined renewable fuels, like methane, biodiesel and bioethanol on a large scale. With regard to the argument over food versus fuel production, it must be said that without energy to make fertiliser and  heat greenhouses, there would  be much less food. Furthermore, if sugar is  “an entirely dispensable food”  (1 February, p 36), would it not be better to turn it into easy-to-store fuels using a combination of existing technologies? Letham, Angus, UK