Known as the Spherical Tokamak for Power Production (STEP), the UK today embarked on a step towards building the world’s first nuclear fusion power plant, launching a search for a more than 100 hectare site where it can connect to the electrical grid.
However, there are still big hurdles to overcome before you can start generating power. No fusion reactor has yet produced more energy than it consumed. That could change in 2025, when the world’s largest fusion project, ITER in France, ignites.
Mast Upgrade (Mega Amp Spherical Tokamak) will use an innovative design known as a spherical tokamak and could remove some of the roadblocks to delivering unlimited clean power to the grid. Most tokamaks are donut-shaped. But in Mast Upgrade, the size of the nut hole has been reduced as much as possible, giving the plasma an almost spherical profile.
STEP’s power production target is more modest (100MW net profit) but, unlike ITER, it will connect to the ordinary power grid to understand how a fusion plant operates day after day.
The plant is presented as an important platform in efforts to reach the UK’s goal of net zero emissions by 2050. The UK is not the only country aiming to build a commercial fusion reactor. A Chinese proposal, the Chinese Fusion Engineering Test Reactor (CFETR), could go online in 2035. And DEMO, the European successor to ITER, is planned for the 2050s.
The UK Atomic Energy Authority (UKAEA), the government body that oversees STEP, expects construction to start around 2030, with the plant running as early as 2040.
The tokamak is a fusion device that uses magnetic fields to confine plasma (hot ionized gas) within a container. This plasma allows light elements to fuse and produce energy.