The near-term feasibility of using helium-3 as a fuel for fusion power hinges on the establishment of a reliable supply chain and the advancement of fusion reactors to commercial operation.
Helium-3 is extremely rare on Earth. However, it is continuously deposited on the Moon’s surface by solar wind, a stream of charged particles emitted by the Sun that contains helium-3.
Rich Brook, CEO of helium consultancy Garrison Ventures, told gasworld the near-term development of a helium-3 supply chain from the Moon’s surface is currently unfeasible, due to several economic and technical challenges.
He estimates it will take around 50 years to begin harvesting helium-3 from the Moon’s surface, while meaningful volumes of any lunar resource could take around 250 years to develop.
This comes amid Californian fusion energy company TAE Technologies (TAE) announcing a with natural resource and lunar development company Black Moon Energy (BME) that covers the prospective supply and commercial development of helium-3 fuel for fusion power.
Under the agreement, BME would supply helium-3 fuel to TAE for its nuclear fusion operations. Separately, BME is pursuing a longer-term strategy to establish a helium-3 supply chain from the lunar surface.
Helium-3 fuel in fusion power
Helium-3 is being studied as a potential fuel for fusion energy, but there are currently no commercial fusion power plants in operation globally.
Most leading fusion reactor concepts initially propose using deuterium and tritium as fuel.
On Earth, helium-3 is produced naturally by the beta-decay of tritium. Trace amounts of helium-3 are also found mixed in with helium-4, but only at around 150 parts-per-billion (ppb), Brook previously told gasworld.
Brook explains, “The helium-3 that we have available for use on Earth is all coming from the transmutation of…tritium.”
“But the only tritium that’s being produced [on Earth] is the tritium that’s being used in nuclear weapons and in the Canadian-designed “CANDU” nuclear power plants where tritium results from neutrons bombarding deuterium atoms in the heavy water that is used as a moderator. The majority of these CANDU nuclear power plants are operating in the Province of Ontario, in Canada.”
Commercial fusion is being targeted by some developers for grid connection in the mid-2030s. The global fusion industry attracted $4.48bn in investment in the past year, according to the Fusion Industry Association.
But more importantly, helium-3 as a future fuel in fusion power hinges on the development of a helium-3 supply chain, which includes many economic and technical challenges.
Challenges of helium-3 supply
Significant investment would be required to harvest helium-3 from the Moon’s surface, with technical challenges ranging from space travel and rocket launches to mining equipment development suitable for the lunar surface. Humans will need to live and work on the Moon.
“The probability of…successfully being able to go to the moon and to start a mining operation, given the fact that you have to haul many, many thousands of tonnes of equipment up to the moon, and then you have to bring back the material from the moon, this is an absolute, very, very complex problem,” Brook explained.
Once at the Moon’s surface, there are also considerable technical challenges associated with the separation of helium-3 from helium-4, he adds.
“[Helium-3 is] mixed at a very attractive ratio compared to the ratio here on Earth [but] the technology to separate helium-3 from helium-4 doesn’t exist.”
In July, US natural resources company Interlune said it had produced 99% pure helium-3 by Grade A helium resources during a lab-scale demonstration at its Seattle facility.
In a separate comment, Brook said that without Interlune providing meaningful details of their process, in all likelihood, the helium-3 recovery rate, processing, and equipment costs would make Interlune’s process “economically challenging.”
He estimates that the current global annual demand for helium-3 is less than five kilogrammes, given there are no operational commercial fusion reactors worldwide. An annual supply of five kilogrammes satisfies the current demand from the two main users of helium-3, neutron detectors, and dilution refrigerators used for quantum computers.
“If you bring back 500kg of helium-3 from the Moon because you think it’s worth hundreds of millions of dollars…you will be very unhappy to learn that 500kg being sold into a market of just 5kg annual demand would result in a complete collapse of helium-3 pricing.”
