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TECH NEWS: Human-made stars and electricity generation

TECH NEWS: Human-made stars and electricity generation

THE probability seems very high that one of our Christmas presents in 2022 will be the ever imminent load shedding. Although it has been going on for years now, it still remains an anomaly for a country like South Africa.

Electricity is at the heart of modern economies and positively correlated to economic growth. Demand for electricity also increases due to rising household incomes, mainly attributable to the electrification of transport and heat (except in South Africa!) and a growing demand for digitally connected devices and air conditioning in summer. Although this is unfortunately not the major reason for South Africa’s lack of electricity, it is mostly true for the rest of the world.

Many forecasters work with the premise that global electricity demand grows on average at 2.1% per annum, with stronger growth in the developing economies.

According to EnerBlue, the electricity consumption by the year 2050 will be 44 403 Terawatt hours (TWh), with renewable energy supplying two-thirds of the electricity supply worldwide by 2050. According to the Millennium Alliance for Humanity and the Biosphere (MAHB) at Stanford University, USA, the world’s oil reserves will run out by about 2052, natural gas by 2060 and coal by 2090, thus forcing the world to look at alternatives.

Although nuclear is seen to only slightly increase to the year 2050 and renewables such as solar PV, Gas, Wind, and Hydro will experience tremendous growth, there is perhaps an underestimated technology that can possibly make an important contribution to electricity generation in future, namely human-made stars or nuclear fusion.

Nuclear fusion should not be confused with current nuclear technology. When people talk about existing nuclear power plants or when president Putin talks about the possibility of nuclear bombs, they refer to nuclear fission. Nuclear fission is the splitting of one nucleus into two, which produces significant energy that can be used to drive a turbine to generate electricity.

Nuclear fusion produces energy by forcing Hydrogen atomic nuclei together. In the fusion reactors scientists use a solution in which a super-heated gas, or plasma, is held inside a doughnut-shaped magnetic field. The heat that is produced by the fusion of the nuclei is then used to drive a turbine. Nuclear fusion is the way that the sun and others stars in the universe produce energy. In the core of the Sun, huge gravitational pressures drive the fusion process at temperatures of around 10 million Celsius.

Sceptics will immediately indicate that scientists working on nuclear fusion have been claiming for many years that it is only a decade away and they still claim the same. However, Professor Dennis Whyte from the Massachusetts Institute of Technology (MIT) hopes to have a fully functioning demonstration plant by 2025 that would be ready to sell electricity to the grid somewhere in the first few years of the 2030s.

Several governments and private companies are planning pilot plants around 2030 and “industrial-scale” fusion energy by 2050. In February this year a breakthrough was experienced when the Joint European Torus (JET) fusion machine at the Culham Centre for Fusion Energy in England was able to produce the record amount of energy of 59 megajoules and averaged a fusion power of around 11 Megawatts by fusing together two forms of hydrogen. Scientists succeeded in creating a mini star inside a reactor and to hold it there for five seconds to produce a significant amount of energy.

To generate this amount of energy only 0.1 mg of tritium and 0.007 mg of deuterium were used. When compared to fossil fuels 1 kg of natural gas or 2 kg of coal would be needed to release the same 59 Megajoules. Star power could help to limit or even totally abandon the use of fossil fuels towards the middle and end of the current century. Interestingly, 93% of fusion companies believe that fusion-produced electricity will be on the grid in the 2030s or before.

Nuclear fusion technology is also much cleaner than burning fossil fuels that produce greenhouse gases. The fusion reaction produces only helium, which does not cause any climate change and is totally safe to inhale. However, like nuclear fission, nuclear fusion also produces radioactive material that has to be stored under special conditions for about a hundred years until the radioactivity wears off.

Many people are scared of nuclear energy and consider it as dangerous. But because the dynamics of fusion are totally different, it is a much safer technology than fission. Nuclear fission reactors have to be kept cool to prevent a meltdown. In contrast, nuclear fusion reactors have to be kept very hot, around one to two hundred million degrees Celsius. In this case, if the heating systems fail, the reaction simply comes to an end.

Fusion reactors need powerful magnets to keep the plasma inside it stable. But the power of the magnets is limited because they run on electricity transported by copper wires. The magnets can only be turned on for a few seconds to prevent the copper wires from melting. This currently limits the amount of energy generated.

One major drawback is therefore the current construction costs of fusion reactors. 30 000 construction workers are working 24/7 to build the Iter fusion reactor in the south of France at an estimated cost of R365.3bn. The reactor was already supposed to open in 2016, but was delayed.

But now, students at Massachusetts Institute of Technology (MIT) under supervision of Professor Whyte, have made a breakthrough that will make reactors dramatically smaller, faster and cheaper to build. They replaced the copper wires with superconductors, which do not heat up. The MIT spin-off company, Commonwealth Fusion Systems, hopes to soon build more powerful magnets to harness the plasma and generate much more energy.

The cost of running the fusion reactors should not be too high, since the fuel is abundant. The heavy hydrogen isotope deuterium, for instance, is found in any water source. Tritium, the catalyst to start the fusion process, is much scarcer and more expensive.

However, human-made stars or fusion technology could in future produce clean, cheap, and almost limitless electricity. It may sound too good to be true, but that is what leading fusion scientists believe fusion technology could deliver as soon as the next decade.

The scientists are backed by growing private finance and large corporates. If the pessimists that believe it will take 20 years or more for fusion technology to realise, are correct, it will not help to fight the effects of climate change in the near future. There are indeed many technical challenges to overcome but perhaps we may see more breakthroughs in the future.

Professor Louis C H Fourie is an Extraordinary Professor University of the Western Cape


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