Given that burning fossil fuels causes climate change, the key to stopping climate change, pretty obviously, is to stop burning them – for generating electricity, heating and cooling homes, moving around, making steel, cooking dinners, and in as many other applications as we can.

We need to do all these things with a different form of energy. We also need ways to carry that energy from place to place and to store it, because – like fossil fuels – it will not always be produced where and when it is needed. There are various options in theory, but in practice only one, electricity, can do all the various jobs we need efficiently, conveniently and economically. And it is time that I spelled out what the five key elements of the future clean energy system are.

The first is renewable generation, with wind turbines and solar panels providing the vast majority. (These are obviously two distinct technologies, but their impact and their growth are so similar that for most purposes they can be treated as one.) In principle other fossil-free forms of generation could play the dominant role, but they will not, for reasons that will soon become clear.

The second element is electricity storage. The traditional form uses water. When electricity is abundant and therefore cheap, pumps push water uphill from a lower reservoir to a higher one. When electricity demand rises, the water flows downhill through a turbine and generates electricity. This approach, pumped hydro, will continue to be necessary and may be supplemented by other new technologies. But the main tool – again, for reasons that will become clear in a few pages’ time – will be batteries.

Batteries also take centre stage in the third key technology, electric vehicles (EVs). These are much more efficient than those powered by petrol or diesel and have far fewer moving parts, hence are much cheaper to run.

The fourth element of the clean energy system is the heat pump. They work like refrigerators in reverse. Fridges are a kind of magical device, when you think about it: the inside of your fridge is colder than the kitchen where it stands, yet heat flows from the inside of the fridge to the kitchen – from a cold place to a warm place. The heat pump works in a similar way, using electricity not to produce heat, but to transport it from the cold outside world into your living rooms and bedrooms. Its superpowers are its reversibility (both heating and cooling) and its efficiency.

Fifth and final on our list is hydrogen. We need to be careful of this gas – not because of its flammability but because of its smell. In many places where you see the word ‘hydrogen’, you can and should smell bullshit. Such is the hype that there is an (admittedly niche) joke that at any energy lecture, the speaker could begin the question-and-answer session by saying ‘The answer is “Hydrogen!” Now – what’s the question?’ Suffice it to say for now that if it’s made via electrolysis, which uses electricity to split water into hydrogen and oxygen, and is reserved for a few specific applications, that’s a good thing. If it’s made from fossil gas, or deployed when cheaper and more efficient options are available, that would be a stupid thing.

Wind turbines and solar panels will generate the vast majority of our electricity. Much of it will be used directly, and some will be stored and used later. This emissions-free electricity will heat and cool our homes and workplaces using heat pumps, and run the vast majority of our transport using electric motors powered by batteries. Spare electricity will split water to make green hydrogen, which will be used to do jobs that the other four elements of the clean energy system cannot, such as providing high-temperature heat for industry and acting as long-term energy storage.

These five technologies are not quite the whole picture. They need to be connected with wires, data and market mechanisms to form a coherent system, where smart appliances respond to demand and hence prices, working for the purse of the owner but also for the smooth running of the entire system. And yes, with the right regulation and management, these two aims can align.

You may be asking yourself a number of questions at this point.

Can this really work?

Yes.

Does this guy have shares in solar panels or electric car companies?

No.

Haven’t we heard all this before, with other technologies? In particular, what of nuclear power, which some proponents in the 1950s claimed would gift us ‘electricity too cheap to meter’?

Yes, they really did claim that.* As prophecies go, it was as successful as claiming that angels will descend to Earth in a spaceship at Christmas and whisk the deserving off to eat honey and bathe in asses’ milk for ever.

To understand why the grand nuclear vision failed to materialise but the five-pronged clean energy one is inevitable, we can turn to an astoundingly simple discovery made almost a century ago, in a field only tangentially connected with energy.

The 1930s in the United States was an era of well-documented hardship for many. But the aviation business was booming, owing to the government’s procurement of planes for delivering mail and interest from all kinds of businesses. Customers were demanding cheaper planes that could carry more people over longer distances using less fuel. It was intensely competitive, and aviation companies had to be agile, innovative and forward-looking in designs and production methods if they wanted to survive.

In 1922, Theodore Wright was a young engineer newly employed at the Curtiss Aeroplane and Motor Company in Buffalo, New York.† It was already a successful company, good enough to win and then retain the Schneider Trophy, the international race for seaplanes and flying boats, making them the only US winners in the race’s history.

In 1925, Theodore was promoted to chief engineer. He began to keep records of various parameters of aircraft construction – for example, how the time needed to build each plane would come down as workers built more of them. He recorded the ratio of expenditure on parts v. labour, how different approaches to construction favoured either short or long production runs, how mechanisation was changing the economics of both design and manufacture, and many other details alongside.

In 1936, Wright published his first academic paper, in the Journal of the Aeronautical Sciences.3 The contents are as functional as the title, ‘Factors Affecting the Cost of Airplanes’. In it, he lays out his key finding: when the volume of production doubles, the cost comes down. Double it again, and the cost comes down again, by the same percentage. Doubling it yet again produces another proportional price drop.

The reasons why encompass the costs of labour, raw materials and overheads. On the labour side, Wright tells us, his costs fell because the workforce became more proficient as the design became more familiar, and because cheaper, less skilled workers could perform more standardised tasks. With materials, a larger production run meant the factory could buy things like sheet metal in bulk, and waste less of it. Finally, a bigger operation reduced overheads such as back-office costs. Wright concluded that doubling the production volume reduced the labour cost by 20 per cent and the material cost by a little less.

Operating as the company was, in a competitive market where sales and income were the bottom lines that mattered, Wright went on to surmise that the relationship he described would have a circular effect: ‘Simplicity and cheapness of design will make possible gradual reductions in prices which will make possible the sale of somewhat greater quantities with cheaper prices brought about by virtue of such quantity increase.’

Production at volume brings the unit cost down. A lower cost means more demand. More people buying the planes increases the production volume. The price falls further. People buy even more. More demand, more production, lower prices, more demand, more production … the cycle turns, pushing forward the growth in ownership of any given aeroplane. Sales increase exponentially as prices fall.

Now here’s the point: Wright’s Law applies equally to any manufactured good.

This is not just a theory. Analysts have plotted the sales volumes and costs of washing machines, mobile phones, cars, dishwashers, and many other items. They have looked at both national and global markets. Whatever and wherever it is, it seems that as standard, the combination of a new desirable mass-produced product and a free competitive market leads to an exponential growth in sales accompanied by a symbiotic fall in the cost.4

In the energy world, logic indicates that Wright’s Law will apply to wind turbines and solar panels, batteries for storage and for electric vehicles, heat pumps and hydrogen electrolysers. All...