On September 5, 2021 engineers achieved a major milestone in the labs of MIT’s Plasma Science and Fusion Center or PSFC where they managed to make a world record magnetic field strength breaking 20 teslas for a large scale magnet. The intensity of this has led many to believe that it is expected to produce a net output of power and potentially usher in an era of virtually limitless power production. Having met all the criteria for the design of the new fusion device, dubbed SPARC, for which the magnets are the key enabling technology it was declared a success. After they finished celebrating they spent the next few months analyzing and testing to push it to its limits to find what could break it to make a better version in the future.
All of that work has been used to put together the Commonwealth Fusion Systems or CFS. The CFS is a combination of six peer reviewed papers that have led to the team believing that the unique design elements could serve as the foundation for a fusion power plant. Before the demonstration on September 5, the best-available superconducting magnets were powerful enough to potentially achieve fusion energy but only at sizes and costs that could never be practical or economically viable. Dennis Whyte who recently stepped down as director of the PSFC and is a America Professor of Engineering, believes that the demonstration has massively lowered the price of watts for fusion reactors, saying “overnight, it basically changed the cost per watt of a fusion reactor by a factor of almost 40 in one day,”.
The process to make usable energy is done by combining light atoms and turning them into heavier ones. The goal of a fusion reactor is to be able to make more energy than it consumes and to be a clean source of energy. The fuel used by fusion power plants is nearly limitless as it uses a form of hydrogen that can be derived from seawater. The fuel is however difficult to store as it requires being held in place by extremely powerful magnetic fields and the fuel needs to be at extraordinarily high temperatures and pressures. Recently a new material was found nicknamed REBCO, REBCO allows super conducting material to work at 20 kelvins or 16 more than without it. This new material brings significant advantages in terms of material properties and practical engineering. Unfortunately it’s not quite as simple as adding REBCO or replacing something with it as it will require starting from scratch and innovating because it is extremely different from what they are used to using.
Superconducting magnets have shown promising results for becoming a clean source of energy. The teams at MIT and CFS have said that they plan to continue testing to further progress saying “That test actually told us exactly the physics that was going on, and it told us which models were useful going forward”. While superconducting magnets may not be widely used to generate power now, they show that they could not only become a significantly cheaper source of energy but also be a clean source of energy.
