The U.S. Department of Energy reported a major scientific breakthrough in nuclear fusion science in December 2022. For the first time, more energy was released from a fusion reaction than was used to ignite it.
While this achievement is indeed historic, it’s important to pause and reflect on the way ahead for fusion energy.
We are professors of sustainable and renewable energy engineering at Carleton University, where we research alternative energy technologies and systems that can move us to a low-carbon future.
We also teach our students how to navigate the treacherous terrain from lab-based findings to real-world applications.
The efficiency of a potential fusion energy power plant remains to be seen. The reported fusion net gain actually required about 300 megajoules of energy input, which was not included in the energy gain calculation. This energy input, needed to power 192 lasers, came from the electric power grid.
In other words, the experiment used as much energy as the typical Canadian household does in two days. In doing so, the fusion reaction output enough energy to light just 14 incandescent bulbs for an hour.
The same is true of nuclear fission, which is the reaction inside current nuclear power plants. The complete fission of one kilogram of Uranium-235 — the fissile component of nuclear fuel — can generate about 77 terajoules. But we cannot convert all of that energy into useful forms like heat and electric power.
Instead, we have to engineer a complex system that can control the nuclear fission chain reaction and convert the generated energy into more useful forms.
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