when Zero means Zero
Zero is a word that we hear a lot these days. Zero emissions the badge on the back of a Nissan Leaf proudly proclaims. Zero carbon energy suggest some fans of renewable or nuclear energy. Net zero emissions say the politicians. When it comes to climate warming potential or localised pollution impact, zero is clearly a good thing. But just as there is no such thing as a free lunch, there is no such thing as zero carbon energy generation. I say this as all generation of material amounts of electricity and liquid/gaseous biofuel involves the initial consumption of concrete, steel, aluminium, petroleum and - often produced using fossil fuel - electricity. Wind turbines sit atop massive (largely hidden) concrete foundations, solar panels typically take decades to repay the embedded electricity, and nuclear plants involve astonishing amounts of alloys produced in coal-fired furnaces. 'Zero emissions' vehicles are true in that they emit no nitrogen oxides ('NOX...