Will we ever stop using fossil fuels? The question matters because fossil fuels are the largest contributor to climate change. Although finding better ways to produce cement, combat deforestation or even reduce the flatulence of cows and sheep would all be welcome, our only hope of dramatically cutting greenhouse gas emissions is to find cleaner methods of generating power.
This won’t be easy. Coal, gas and oil are wonderfully concentrated sources of energy, neatly synthesising aeons of solar radiation. The late Professor David MacKay, author of the remarkable Sustainable Energy — Without the Hot Air (2008), underlined that truth with the book’s pointed dedication “to those who will not have the benefit of two billion years’ accumulated energy reserves”. The concentrated nature of fossil fuels means that alternative energy sources are competing against a formidable head start; the head start is lengthened by the fact that our entire existing energy system revolves around fossil fuel.
Despite all this, there are two obvious scenarios in which we might replace fossil fuels with alternative energy sources for purely commercial reasons. The first is grim: we begin to run out of fossil fuels and they become too expensive to use as a source of bulk energy. The second, more benign possibility, is that alternative energy sources become so cheap as to outcompete coal, gas and oil at almost any price; as the former Saudi oil minister Sheikh Yamani once commented, the Stone Age did not end because we ran out of stones.