One look at your energy bills this winter might have convinced you that the 1950s idea that electricity would, in the near future, become “too cheap to meter” was not so much a false promise as a sick joke. That over-excited claim was prompted by hopes that nuclear fusion – the process triggered in an uncontrolled manner in hydrogen bombs – would soon be harnessed for power generation. In the type of nuclear power we have today, disintegration of radioactive atoms such as uranium produces heat but also a troublesome legacy of radioactive waste that will stay active for millennia. Fusion power plants would instead generate energy using the same process that powers the sun: fusing of the dense nuclei of hydrogen atoms, releasing some of the formidable energy held in the atomic nucleus, with only helium as the byproduct, and without the pollution.
Today the allure of fusion energy lies not so much in its price as its almost negligible carbon emissions, and therefore its potential to save us from the ravages of global heating. But will it arrive in time to stop the planet frying?
There are plenty of uncertainties and unknowns around fusion energy, but on this question we can be clear. Since what we do about carbon emissions in the next two or three decades is likely to determine whether the planet gets just uncomfortably or catastrophically warmer by the end of the century, then the answer is no: fusion won’t come to our rescue. But if we can somehow scramble through the coming decades with makeshift ways of keeping a lid on global heating, there’s good reason to think that in the second half of the century fusion power plants will gradually help rebalance the energy economy.
Perhaps it’s this wish for a quick fix that drives some of the hype with which advances in fusion science and technology are plagued. Take the announcement last December of a “major breakthrough” by the National Ignition Facility (NIF) of the Lawrence Livermore National Laboratory in California. The NIF team reported that, in their efforts to develop a somewhat unorthodox form of fusion called inertial confinement fusion (ICF), they had produced more energy in their reaction chamber than they had put in to get the fusion process under way.
Problem solved? Sadly not. As NIF scientists readily admitted, the energy generated by super-intense laser needed to spark fusion was less than a hundredth of the total amount of energy consumed by the lasers themselves. So they still have to do about a hundred times better to break even. And that’s even before factoring in the energy losses in converting the heat created by fusion into electricity. What’s more, the hi-tech pellets containing special forms of hydrogen used as fuel each cost more than $100,000, whereas a working ICF reactor would need to burn up 10 pellets a second at a cost of less than $1 each. [Continue reading…]