How Do You Make Electricity?
Ivo van Vulpen—
One of the greatest threats to our prosperity and way of life is a shortage of energy. We don’t often pause to think about it, but our Western society is addicted to energy, and without electricity, it would come to a complete standstill in less than a day. Try to imagine a typical working day without electricity: no alarm clock, no lamps, no coffee machine, no car, no elevator, no ATMs, no television, no computer, no radio, no Internet, no telephone, and no dishwasher. You can clearly see why energy is such a hot topic of public and political debate. This book is not the place to review all the facets of this complex issue, such as the earth’s finite supply of fossil fuels, the geopolitical interests at stake, carbon dioxide emissions, green energy, and the nuclear power debate. You could fill a library with expert studies of those subjects, and the debates are still in full swing. My job here, as a physicist, is to raise a question that I know doesn’t play a central role in the discussion, but which I’d like everyone to be able to answer: How do you make electricity? For example, how do you turn a charcoal briquette, the kind you use in your barbecue grill, into an electrical current? We can do that thanks to a secret that nature revealed to us through one simple observation. The discovery of this seemingly straightforward law of nature changed our lives and our civilization fundamentally.
Some one hundred and fifty years ago, James Maxwell managed to capture all known facts about electricity and magnetism in four famous formulas that have carried his name ever since: the Maxwell equations. They show that magnetism and electricity are intimately interrelated, and they describe electromagnetic phenomena that can be extremely complex—including a regularity discovered earlier by Michael Faraday that gives us a way of making electricity.
Observation (and law of nature): A current starts running through a coil of copper wire when the magnetic field in the center changes.
That may not sound so exciting, but if you take a coil of copper wire and move a magnet through it, it really happens. The magnetic field is absent at first, becomes very strong as you move the magnet into the center of the coil, and then disappears once the magnet has been removed completely. This change creates an electrical current in the wire. That’s the simplest way I can put it. But I couldn’t make it much more complicated either. So there it is: the principle that allows us to generate electricity, whether in a bicycle lamp or in the most up-to-date nuclear power plant.
When you ride a bicycle, you generate the power for your own lamp. A hub dynamo is basically a very long, rolled-up copper wire, like the long iron wire coiled neatly around the hose of a vacuum cleaner. Inside that tube of coiled wire is a magnet connected to your wheel by a gear called a roller. As you pedal your wheel turns, and so does the magnet. And because of the law of nature we discovered, which says that changing the magnetic field in the tube of copper wire will make a current run through it, a current really does run through it. This current is then conducted through a thin metal wire into the lamp, making it warm up and start to glow. Ta-da: a bicycle light. And not to make the high-tech energy giants seem unimpressive, but a big coal-fired power plant works about the same way. There too, a magnet is rotated inside a coil of copper wire. The only difference is how you move the magnet. On your bicycle you do that by pedaling, while in a power plant the work is done, surprisingly enough, by a turbine. The turbine spins because of steam pushing hard against the blades, which are connected to the magnet by a gearbox. So how do we make steam? By heating up a large container of water. And how do we heat the water? By burning a heap of coal underneath it. It’s that simple.
Of course, thousands of people work hard every day to make each step of this process as efficient as possible in power plants, and much more is involved than I describe here, but this is the basic principle. And a nuclear power plant works almost the same way. The only difference is how you heat the water. In a nuclear plant, this is done by the particles released when you split the nuclei of heavy atoms such as uranium. Wind energy uses the same principle: the spinning blades of the turbine turn a magnet inside a copper coil.
This very simple principle—generating current by changing a magnetic field—is fundamental to our economy and therefore to our prosperity. When Faraday first made these discoveries, no one could suspect how they would be applied. William Gladstone, who was in charge of the British Treasury, is said to have asked Faraday, “But, after all, what use is it?”—an understandable question from his point of view. It is the same question that scientists are still asked today whenever we apply for research funding. Unfortunately, we can no longer get away with Faraday’s famous reply: “Why, sir, there is every probability that you will soon be able to tax it!” Back then, people were fairly content with candlelight, and it probably seemed more sensible to give money to the candle industry to find a more efficient production method or design a better wick. But in retrospect, we can see that we would never have discovered the light bulb that way.
Even though a lot of scientific research leads absolutely nowhere, this is a striking example of how true innovation can’t always be planned in advance. The game-changing discoveries often come from unexpected places. That’s an important message for politicians and for society as a whole: alongside innovation for industry, we need to create enough opportunities for free, unrestricted fundamental research. Applications are sure to follow.
From How to Find a Higgs Boson—and Other Big Mysteries in the World of the Very Small by Ivo van Vulpen, translated by David McKay. Published by Yale University Press in 2020. Reproduced with permission.
Ivo van Vulpen is a particle physicist working at the University of Amsterdam and at Nikhef, the Dutch National Institute on Subatomic Particles. He is a member of the ATLAS experiment at CERN and lives in Leiden, Netherlands.