Pioneering commercial
fusion technology
Pioneering commercial
fusion technology
The spherical tokamak
Tokamaks are the most researched and best understood path to fusion energy.
A tokamak is a device that uses magnetic fields to confine and control a plasma. Scientists first recognised the potential of tokamaks to achieve fusion conditions in the 1960s. Decades of extensive research and development have established tokamaks as the leading approach in the pursuit of commercial fusion energy.
In the 1980s, a study by one of our founders, Alan Sykes, demonstrated that altering the shape of the tokamak could significantly enhance its performance. The compact spherical tokamak, with its more compressed, spherical design, was found to provide key benefits in terms of efficiency, plasma stability, and cost-effectiveness. This design now underpins fusion energy programs worldwide, including the UK Government’s Spherical Tokamak for Energy Production (STEP) project.
Tokamak Energy is the only private company with over a decade’s experience developing and operating tokamaks.
ST40
Our ST40 high-field compact spherical tokamak is the most advanced of its kind in the world.
In 2022, we reached a world-record plasma ion temperature of 100 million degrees Celsius, the threshold for fusion energy. At the same time, we achieved the highest ‘triple product’ of any private fusion company, a crucial metric of plasma performance that includes temperature, density, and confinement time. Our achievement was documented in a peer-reviewed scientific paper published by the Institute of Physics in 2023.
Our ongoing work with ST40 continues to advance the physics and technology basis for the high-field spherical tokamak route to commercial fusion. In late 2024, we announced an exciting $52 million ST40 upgrade program in collaboration with the US Department of Energy and the UK Department of Energy Security and Net Zero. This program focuses on lithium plasma-facing components, a key technology for future fusion power plants.
HTS magnets for fusion
Tokamaks use strong magnetic fields to control the shape and position of the plasma, trapping it long enough for fusion to occur.
High temperature superconducting (HTS) magnets generate these fields at higher temperatures than conventional superconductors, making them more than five times as energy-efficient. Combining the increased efficiency of the spherical tokamak with the improved magnetic confinement made possible by high-field HTS magnets offers the most viable and cost-effective route to fusion energy.
Tokamak Energy is a world leader in HTS technology. Our fusion magnet coils are wound from HTS tapes, which are multi-layered conductors typically 12mm wide and less than 0.1 mm thick made mostly of strong and conductive metals, but with a crucial thin internal coating of ‘rare earth barium copper oxide’ (REBCO) superconducting material. Our advanced winding, testing and production techniques are the key to creating robust and reliable HTS magnets.
HTS is a transformative technology for getting clean, limitless fusion energy on the grid faster.
Demo 4
Our Demo4 magnet system, currently under construction in a purpose-built test facility, is the next key step on our pathway to fusion energy.
Demo4 is designed as a complete balanced set of HTS magnets in a tokamak configuration, which will allow us to test them in fusion power plant-relevant scenarios for the first time.
It comprises of 44 individual HTS coils assembled into 14 toroidal field limbs and two poloidal field coils, forming a cage-shaped structure. The system will operate in a vacuum at 20 Kelvin (-250°C) and will have a magnetic field strength of nearly a million times stronger than the Earth’s magnetic field.