Earth Talk: Nuclear fusion

Dear EarthTalk: Why are Bill Gates and Jeff Bezos, among others, so bullish on developing nuclear fusion as a power source? -- Mark P., Newton, Massachusetts

Answer: While nuclear fission is commonly used in nuclear power plants across the globe, nuclear fusion is a lesser-known process.

Whereas fission is the process of releasing energy by splitting atoms apart, fusion is the opposite. During nuclear fusion light nuclei collide with each other to form heavier nuclei, a process that releases large amounts of energy. Producing fusion requires a combination of the hydrogen gasses deuterium and tritium, which are heated to over 100 million degrees Celsius. The end result is a helium nucleus and a neutron, formed from the collision of light nuclei.

Fusion power offers so many advantages that many have heralded it the “Holy Grail” of clean energy. The most enticing advantage is that nuclear fusion produces no carbon emissions. The only byproducts of the reaction are small amounts of helium. There are also abundant resources to produce fusion. Deuterium can be extracted from water and tritium can be produced from lithium. Nuclear fusion offers a safer alternative to nuclear fission, as a large-scale nuclear accident is not possible in a fusion reactor. And unlike fission, there is no radioactive waste as a result. The energy efficiency of fusion is another major advantage. One kilogram of fusion fuels could theoretically provide the same amount of energy as 10 million kilograms of fossil fuel.

Many billionaires and tech moguls have recognized the potential of nuclear fusion and have invested in its future, Bill Gates being the most well-known. Founded by Gates in 2015, Breakthrough Energy Ventures is a fund set up to invest in clean energy transition innovations. Breakthrough Energy is supported and funded by other...