It seems that more people are now beginning to realise that, to be a real game-changer rather than just an expensive and unreliable contributor to energy needs, solar, wind and other sources of renewable, ‘free’ energy have to be used in conjunction with energy storage on a massive scale. Not only that, but this scale is far greater than anything we can currently conceive of. Even pumped storage, the best we currently have, could make only a very modest contribution in most geographies.
Batteries, including the Tesla Powerwall, are touted as an enabler of a true renewables revolution, but they can at best only cover such things as overnight domestic consumption or bridge local shortfalls over short timescales. They have their place, but not as a way to transform electricity supply grids. These sorts of issues are touched on in a recent article in the Times by the economics editor of Sky News, Ed Conway (Unlimited energy is more than a pipe dream).
He leads with a few paragraphs about the Californian start-up Ares, which is testing the use of trains on inclines as a way of storing energy; rather like pumped storage, surplus energy is used to power the train uphill and part of that energy is recovered when needed by running the train down again. This is unlikely to make a major contribution to the overall supply, but shows that a degree of ingenuity is needed to tackle this very important problem of how to use renewable energy as a despatchable source of electricity.
The article gives a fairly balanced view of the position, although verges on the optimistic at times. To quote, “Indeed, one might envisage a world entirely powered by renewable energy. A few months ago the Lappeenranta University of Technology in Finland created a computer model which proved, in theory if not in practice, that the world could sustain itself on renewable energy at a price close to the cost of fossil fuel power today. As you might expect, the model involves some gargantuan leaps of faith: that Britons would be OK with tens of thousands more giant windmills carpeting the countryside; that if the wind were not blowing in one country it would always be blowing somewhere near by; that countries would be willing to sacrifice self-sufficiency for ever. But with every day that goes by, the model looks a little less implausible.”
However, it finishes on a somewhat more realistic note: “It is easy when you read about trains that are batteries and batteries that are countries to forget that for now fossil fuels still provide more than 90 per cent of British energy. When you hear that Britain has just powered itself for a full day without any coal for the first time since the Industrial Revolution, you might not realise that we will nonetheless need carboniferous fuels for decades. That, for the time being, coal is still by far the cheapest source of energy. The real challenge in the coming decades is not just to aim for a future of green energy but to manage the decline of an industry which has powered Britain for the past two centuries. There is little sign, yet, that the government has realised this, let alone prepared for it.”
This seems a bit like putting the cart before the horse. There is no point in managing the decline of fossil fuel generation until the technology to replace it is available. The scale of the challenge is highlighted in a letter commenting on Ed Conway’s article by Sinead Lynch, chairwoman of Shell UK in the Times. Her key argument goes thus: “Electricity counts for about 18 per cent of world energy use. Even if all electricity turned zero carbon overnight we would still have 82 per cent of the energy system to decarbonise. British’s power sector had a day without coal recently. A real milestone, but on that day cars still drove, planes flew, cargo ships sailed, and people cooked their food and heated their homes. Not much of that was done with electrons . . . not nearly enough, anyway. There is much work left to do.”
This is why slashing carbon dioxide emissions as radically as countries such as Germany and the UK intend is, with current technology, virtually impossible. Nearly everything we currently use energy for – domestic and commercial lighting and heating, computer centres, manufacturing industry and road transport in particular – would have to run on electricity. But not just any electricity; all of it would have to be generated without the use of fossil fuels.
The scale of the problem with the present electricity grid alone is quite apparent. Generators have to get that right first. Whatever computer models may tell us, observational evidence shows clearly that there will be quite long periods from time to time when the wind doesn’t blow over either in the UK or across vast swathes of Europe. Some of these will be during the winter, when the contribution to the grid from solar panels is very small. Carpeting the countryside with wind turbines and solar panels can never guarantee security of supply. And that’s just for the 18% of total energy that comes from electricity.
Then, the generating and transmission network has to be multiplied three- or four-fold to supply all the energy for heating, lighting, road transport and manufacturing and the cars, heating systems and manufacturing plant developed and installed. This is an absolutely massive task and one which we are nowhere near capable of undertaking yet. Imagine the task of converting all houses and offices from gas or oil to electric heating systems. Even the comparatively trivial task of moving to ‘smart’ meters is taking many years and costing an estimated £10 billion.
None of these arguments mean that there is no future for renewable energy or that the vision of an all-electric world is impossible. But they do mean that there is no point in trying to fulfil that vision without the right technology. At some stage, we will no longer rely on coal, gas or oil to power our societies. But the transition can only take place once there is an economically and technically viable alternative.
Horses were only displaced as the primary motive force for travel when steam and petrol engines had developed sufficiently. Fossil fuel energy will only become yesterday’s technology when energy storage becomes available on a massive scale or some new development leapfrogs our current attempts to harvest renewable energy. Highly efficient harvesting and storage of solar energy could be our best bet, but we’re a long way from that yet.