A green planet will be run by pieces of silicon.
Renewable electricity has an awkward habit: it arrives in the wrong form. Solar panels make direct current; the grid wants alternating current. A battery holds a few hundred steady volts; a motor wants a shape that changes thousands of times a second. Every one of those conversions is done by a power semiconductor flicking on and off faster than you can think — and every flick wastes a little energy as heat. So the climate arithmetic of a solar farm or an electric car rests on how good those switches are.
- On every arrow
Wherever the form of the electricity changes, a power transistor is doing the switching.
- Why the material changed
Silicon carbide and gallium nitride hold higher voltages and switch faster, so less energy becomes heat.
- 1On every arrow — Wherever the form of the electricity changes, a power transistor is doing the switching.
- 2Why the material changed — Silicon carbide and gallium nitride hold higher voltages and switch faster, so less energy becomes heat.
One semiconductor swap, applied to every lamp on Earth. Lighting was roughly a sixth of world electricity demand before it happened.
Cheap, mature, everywhere. Runs out of headroom at high voltage and high frequency.
Dearer per device, but smaller, cooler, lighter systems — which is why they reached cars first.
Decarbonising is, in large part, an engineering fight over how much heat a switch wastes.