I was initially highly sceptical about solar energy and its ability to become economical. I first visited a solar factory in 2003 on behalf of a client who wanted to invest in a Berlin-based solar business.
At the time, a 200-watt solar panel cost US$1,400, with the business model supported by heavy subsidies from the German government. Today a solar panel costs $60 and is the cheapest way to produce electricity across most of the world. I am now fully convinced that continuing cost reductions and improvements in energy storage technologies will enable solar to not only drive the electrification of our world but also become the most critical energy source of the 21st century.
What I saw, when I visited that Berlin solar business was nothing more than a garage-type affair with employees producing panels by hand. I thought it was all a bit of a joke and told my client that he had better things to do with his money. He suggested I meet the founder, a man named Alex Voigt. He explained to me that Albert Einstein won the Nobel Prize for physics in 1921 not for the Theory of Relativity but for the Photoelectric Effect, the process by which solar photovoltaic (PV) systems convert the sun’s energy directly into electricity. He went on to explain the solar cell was a semiconductor and that, just as microchips get cheaper and cheaper to produce, costs for solar would decrease from year to year and power output would increase.
How right he was…today that same solar panel has 50% more power output than in 2003 and costs have fallen by over 90%. We have also never seen an energy technology come to market so quickly. In 2003, solar installations totalled 365MW across the globe. Last year, there was over 115,000MW installed, which is more than all other power generation technologies (coal, nuclear, gas, wind, hydro) put together!
All this begs the question: why has solar taken off so quickly?
It goes back to first principles.
The source of nearly all useful energy on our planet, with minor exceptions, is the sun. Without the sun we would have no food, no animals, no trees and no biomass feedstock. Besides, the process of photosynthesis, taking place over many millennia of the Earth’s history, has left us with a valuable legacy of fossil fuels like coal, oil and natural gas.
But the exciting thing is that enough energy falls on the surface of our planet each day to surpass our current energy needs by 10,000 times. The issue for all of us is how best to extract and use that energy. The answer to that is increasingly clear: taking the sun’s energy and converting it directly into electricity gives us the most useful and controllable form of energy we know.
As electricity is so controllable, less energy is wasted through heat loss, which is why an electric vehicle is three times more fuel-efficient than an internal combustion engine-powered car. In practical terms, no matter where you are in the world, it is cheaper to run your car on electricity than on diesel or gasoline. And that gap is only going to widen as solar gets cheaper.
One of the significant advantages of solar PV is that it can be used in both small and large-scale installations. It can be used to power calculators, mounted onto roofs or façades, or configured in large-scale plants. Plus, installation is quick and straightforward. Whereas a nuclear power station with a GW of power capacity could take at least ten years from inception to generating its first megawatts of power, solar can be deployed at breath-taking speeds. China, for instance, installed some 30GW of new solar capacity (30 nuclear power plants) last year. Nearly all of these systems required less than six months to plan, construct, and connect to the grid to start delivering power to the public. Solar’s steep cost curve has fuelled its viral expansion and that trend will continue.
On the technology front, the next big step in solar is the move to tandem cells. These cells are highly disruptive because their introduction does not require a radical re-equipping of existing production lines but instead additional equipment which coats thin-film layers of materials such as perovskite onto standard crystalline silicon cells. This is what companies like UK-based Oxford PV are doing and such innovations could drive an increase in efficiency from 22% at present towards 30%.
Of course, there is still the issue of what to do when there is no sun, either at night or during times of heavy cloud cover. Such intermittency issues can be overcome with storage, and in the future, we will store electricity in and batteries in our homes, businesses and motor vehicles.
Meanwhile, we will convert excess electricity into hot water for use in our buildings and we will build a more digitalised and connected power grid to move the energy from where it is produced to where it is needed. We will also continue to use existing fossil fuel storage facilities as back-up and eventually we will convert them to hydrogen and other e-fuel facilities.
All those years ago Alex Voigt also said to me: “if we cover a small part of the Sahara Desert with solar panels, we can power the whole world”. I thought he was mad at the time but now you probably think I am mad for saying solar will become the bedrock of our 21st-century energy system just as oil and gas were in the 20th century.