General Fusion: Are They Back In The Game?

One of the areas that The Fusion Report has been covering since its inception is the continued funding of fusion companies. The concept is simple – funding represents votes by “people with money” on both the concept of fusion, and the specific team at that company. That said, most of those doing the betting are venture capitalists (VCs), who expect to lose more of their bets than they win, but to “cut out the losers” early.

That is why the announcement by General Fusion last week of the closing of an oversubscribed $22M funding round was in some ways surprising. Just 3-1/2 months ago, General Fusion announced in an open letter from their CEO that they were cutting back on both their team and their fusion operations due to a lack of money. These cutbacks included (at least) a 25% reduction in its employees. Usually, cuts that deep are harbingers of more bad news to come, which is why last week’s successful round, even though only $22M (not big by fusion standards), is meaningful. The new investment was led by Segra Capital (a twelve-year old VC firm based in Florida, and focused on the energy markets) and PenderFund (a 20-year old Canadian mutual fund company), both who now have a seat on General Fusion’s board of directors.

General Fusion – Not  Your Normal Approach to Fusion Energy

While most fusion systems utilize either magnetic confinement fusion (MCF) or inertial confinement fusion (ICF), General Fusion combines aspects of both approaches (plus a few novel ones) to cause the fusion of a hydrogen plasma using a technology that they call “Magnetized Target Fusion” (MTF). The keystone of MTF is the use of steam-powered “pistons” to compress the plasma. The second keystone is the use of a liquid metal “first wall” which both protects the solid structure of the fusion machine, while also collecting heat from the neutrons produced by the fusion, as well as generating tritium (the liquid metal contains lithium). The name of their current machine is “LM26”.

The illustration below (from a General Fusion video on YouTube) shows conceptually how the MTF process works. Steam pressure in the horizontal tubes forces the pistons (the solid red cylinders in the illustration) inward towards the center of the vessel.  This compresses the liquid metal, which itself compresses the hydrogen plasma in the center of the vessel. This approach only requires a confinement time of 10 milliseconds, which General Fusion exceeded in trials earlier this year, the results of which were confirmed by a peer-reviewed paper. In fact, they achieved 10 million degrees C in similar trials.

General Fusion’s Next Steps Towards Commercial Fusion Energy

While 10 million degrees C is a great achievement, it is not what General Fusion needs to achieve scientific break-even, or to demonstrate that MTF is relevant to commercial fusion energy. To do this requires several steps, as follows:

• Achieve a plasma temperature enabling scientific break-even: Based on General Fusion’s research, the next step they plan to achieve is to generate a plasma temperature of roughly 100 million degrees C, which is required to achieve scientific break-even (fusion energy out equals energy put into the machine), along with confinement time. General Fusion expects to achieve 100 million degrees C in late 2025, and scientific break-even next year (in 2026), both of which General Fusion plans to do with the funding that they just raised.
• Build a Half-Scale Demonstrator Fusion Machine: The next step is going towards fusion commercialization. This takes more than a single “compression event”, and certainly more than scientific break-even: it requires repeated compressions (perhaps one per second), at a Q (the ratio of output power to input power) at least 10X of scientific break-even (Q=1). While General Fusion has not stated a target date for this, it will almost certainly require another fund raise, and one much larger than the $22M that they raised this month.

Summary: Progress, but Still A Long Way to Go

As Oded Gour-Lavie (CEO and co-founder of nT-Tao, an Israeli company developing modular fusion systems) stated in an interview with The Fusion Report a couple of months ago, “Fusion is not science fiction, it is science. It just isn’t easy.” Like most of the commercial fusion energy development programs, whether General Fusion’s approach will achieve scientific break-through is something that we will know in the next couple of years; whether (and how long) it takes to reach commercial viability will probably take 5-10 years (i.e., in the early 2030s), and will likely require a lot more money than the company has raised so far. On the other hand, you have to “eat the elephant one step at a time”, and getting their $22 million certainly represents an important bite at the elephant.