Where Does the Electricity in the Wall Come From?插座裡的電從哪裡來？

🔊Plug in a phone charger, and electricity is there instantly, day and night. A battery runs out, but the outlet in the wall never seems to. Where does that electricity come from? Follow the wires behind the wall, and they lead to a power line, then to a substation, and finally to a power plant that may be far away. And inside almost every power plant, you will find the same simple thing: a magnet that spins.

🔊In 1831, the English scientist Michael Faraday discovered something amazing. When he moved a magnet near a coil of wire, electricity flowed in the wire. When the magnet stopped, the electricity stopped too. A magnet sitting still does nothing; it is the change, the movement, that pushes the electrons. This is called electromagnetic induction, and almost every power plant in the world depends on it.

🔊A generator is a faster, bigger version of Faraday's experiment. A magnet spins next to coils of wire. As the north pole sweeps past a coil, it pushes the electrons one way. Half a turn later, the south pole sweeps past and pushes them the other way. So the current keeps changing direction. This is called alternating current, or AC. In Taiwan, the current makes 60 complete back-and-forth cycles every second, which is why we say the power is 60 hertz.

🔊So what turns the magnet? In most power plants, it is a turbine, a wheel with blades, pushed by something moving fast. Coal and nuclear plants boil water into high-pressure steam that blasts through the turbine. Gas plants burn natural gas in a turbine like a jet engine, and many also use the leftover heat to make steam. At a dam, falling water turns the turbine, and on a wind farm, the wind does. Only one common source works differently: solar panels turn sunlight into electricity with no moving parts at all.

🔊From the generator, electricity travels across the island on tall towers. To travel far with little waste, it is raised to a very high voltage; Taipower's biggest lines carry 345,000 volts. Substations step it down again and again, until a transformer near your street lowers it to the 110 volts in your outlet. The electrons in your wall do not travel all the way from the power plant. They just wiggle back and forth in place while the energy rushes along the wires.

🔊So where does Taiwan's electricity come from? In 2025, about 48% came from burning natural gas, 35% from coal, 13% from renewable sources such as solar and wind, and about 1% from nuclear power. Taiwan's last nuclear reactor shut down in May 2025. Every choice has a cost: coal and gas release carbon dioxide, and the sun and wind come and go with the weather. But apart from solar panels, all of them come back to the idea Faraday found almost two hundred years ago: spin a magnet, and the electrons move.