The UK's newest fusion reactor, ST40, was switched on last week, and has already managed to achieve 'first plasma' - successfully generating a scorching blob of electrically-charged gas (or plasma) within its core.
The aim is for the tokamak reactor to heat plasma up to 100 million degrees Celsius (180 million degrees Fahrenheit) by 2018 - seven times hotter than the centre of the Sun. For this reactor, that's the 'fusion' threshold, at which hydrogen atoms can begin to fuse into helium, unleashing near-limitless, clean energy in the process.
"Today is an important day for fusion energy development in the UK, and the world," said David Kingham, CEO of Tokamak Energy, the company behind ST40.
"We are unveiling the first world-class controlled fusion device to have been designed, built and operated by a private venture. The ST40 is a machine that will show fusion temperatures - 100 million degrees - are possible in compact, cost-effective reactors. This will allow fusion power to be achieved in years, not decades."
Nuclear fusion is the process that fuels our Sun, and if we can figure out a way to achieve the same thing here on Earth, it would allow us to tap into an unlimited supply of clean energy that produces next to no carbon emissions.
Unlike nuclear fission, which is achieved in today's nuclear reactors, nuclear fusion involves fusing atoms together, not splitting them apart, and it requires little more than salt and water, and primarily produces helium as a waste product.
But as promising as nuclear fusion is, it's something scientists have struggled to achieve.
The process involves using high-powered magnets to control plasma at ridiculous temperatures for long enough to generate useful amounts of electricity, which, as you can imagine, is far from simple.
Over the past year there have been some big wins. Scientists from MIT broke the record for plasma pressure back in October, and in December, South Korean researchers became the first to sustain 'high performance' plasma of up to 300 million degrees Celsius (540 million degrees Fahrenheit) for 70 seconds.
But we're still a long way off being able to put all those pieces together - finding an affordable way to generate plasma at the temperatures required for fusion to occur, and then being able to harness it for long enough to generate energy.
The next step is for a full set of those magnetic coils to be installed and tested within ST40, and later this year, Tokamak Energy will use them to aim to generate plasma at temperatures of 15 million degrees Celsius (27 million degrees Fahrenheit).
In 2018, the team hopes to achieve the fusion threshold of 100 million degrees Celsius (180 million degrees Fahrenheit), and the ultimate goal is to provide clean fusion power to the UK grid by 2030.
Whether or not they'll be able to pull off the feat remains to be seen.
But the company is now one step closer, and as they're not the only ones with a tokamak reactor in development, it will hopefully only speed up the race to get a commercial fusion reactor online.
Watch this space.