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Fusion is the process by which the sun and stars generate energy. The blast furnace that is our sun generates temperatures and pressures that drive hydrogen atoms to collide and fuse.
How can fusion be harnessed to generate power here on Earth? One company, General Fusion, is developing magnetic field fusion energy and collaborating with Canadian Nuclear Laboratories on a project to advance fusion energy technologies. General Fusion and the Canadian laboratory are attempting to develop tritium extraction processes for commercial fusion power plants. Elsewhere, the U.K. Atomic Energy Authority (UKAEA) also is partnering with General Fusion to develop its Fusion Demonstration Plant in the United Kingdom. Following completion of a new facility at Culham, General Fusion will sign a long-term lease with UKAEA. The demonstration plant will showcase General Fusion’s fusion technology, paving the way for what the company hopes will be its commercial pilot plant.
Jay Brister, chief business development officer at General Fusion, said private investments in fusion energy are increasing, with more than $2 billion committed by private companies to date. “Regulators around the world are also exploring the authorizations which are necessary to support fusion energy,” Brister added. “Fusion energy will benefit countries looking to transition toward net-zero carbon emissions to achieve their climate goals.”
Groups like the Fusion Industry Association “are engaging with government agencies to develop a regulatory framework for commercial fusion energy in the United States. In the United Kingdom, the Regulatory Horizons Council is pursuing a similar path,” Brister noted.
Increased R&D investment in fusion energy is driving a more realistic view of the technology as a viable option to provide abundant and reliable electricity. But obstacles remain, including the need to upgrade the existing power grid to support the diverse energy sources.
“Energy grids are going to evolve over time – especially with the implementation of more renewables,” Brister said. “One of the advantages of fusion is it is energy dense and requires minimal land use. Fusion energy power plants will also reduce the need for long transmission lines because they can be built near the sources of energy demand, making better use of land.”
He added, “The distributive nature of where electricity grids are going – having the ability to provide a localized and dispatchable source in a size that will complement a renewables portfolio will be key. It will be a part of a broader clean energy portfolio.”
Fusion energy proponents say their industry must play a greater role in reducing emissions and solving climate change, along with solar and wind power.
“As the world seeks to combat climate change, energy providers around the globe are upgrading their infrastructure to reduce carbon emissions. A strong energy system needs both firm power and intermittent power. Fusion energy is on-demand and independent from the weather, making it an excellent complement to renewables,” Brister asserted.
Carbon-free “firm” power promises to reduce emissions and meet the growing demand for electricity while replacing aging infrastructure. “Electricity demand is projected to grow by 200 percent by 2050. Fusion energy offers utilities a powerful addition to the mix of electricity generation options to meet this growing demand,” added Brister.
Fusion explained. (Source: General Fusion)
Magnetized Target Fusion
An electromagnet is a coil of wire wound around a mechanical shape. When electricity flows through the wire, it creates a magnetic field in and around the coil. If the wire is wound several times, the strength of the field is multiplied by the number of wire loops used. However, a copper coil will resist the flow of electricity, dissipating energy as heat. Resistive heating is acceptable if the coil is switched on briefly and then allowed to cool.
Superconducting magnets are made of niobium-titanium with no electrical resistance when kept cold. This allows the wire coil to handle large electrical currents for long stretches without dissipating heat. However, materials like niobium-titanium require large and expensive cryogenic cooling systems to operate.
General Fusion uses a plasma confinement method dubbed Magnetized Target Fusion (MTF) that relies on simple electromagnets operating on a pulsed basis. This method achieves fusion, which can then be repeated in a cycle.
It works like this:
- A vessel is filled with liquid metal, which is spun until the metal forms a cavity.
- Hydrogen plasma is Injected into the resulting cavity.
- The plasma is compressed and heated to more than 100 million degrees Celsius, and fusion occurs.
“The fusion process heats the liquid metal wall. In our commercial pilot plant, the heat will be extracted from the metal and used to make steam. The steam will drive a turbine – producing electricity,” said Brister.
MTF uses electromagnets in the plasma injector. An injector generates a ring of plasma and, through the swirling motion, it creates a magnetic field that forms a cloud of particles. During the short life of the plasma ring, it is compressed to temperatures and pressures at which nuclear fusion should occur.
The plasma particles flow along the magnetic field lines, which then circulate without ever touching the wall. In this way, the magnetic field prevents hot fusion plasma from touching the liquid metal and cooling. The magnetic field acts as an excellent thermal insulator as the plasma core is heated. During the process, Brister said the walls of the tank remain cool enough to function as part of a power plant.
MTF has four key advantages, General Fusion claims: material durability, fuel production, energy conversion, and energy economics.
- Material durability: The liquid metal liner shields the MTF structure from neutrons released by the fusion reaction, overcoming the problem of structural damage to plasma-facing materials (also called the first wall problem).
- Fuel production: The fusion process starts with filling a tank with liquid metal, spinning the metal until a cavity is formed. General Fusion injects hydrogen plasma into the cavity. “We use high-powered pistons to compress the plasma to fusion conditions,” Brister explained. “High-speed digital controls manage and synchronize the timing of 500 individual pistons. The compression process happens in milliseconds. Fusion occurs as the liquid metal compresses the plasma resulting in a release of energy and tritium, which will be captured and used as fuel.”
- Energy conversion: In the pilot plant, heat would be extracted from metal and used to make steam. The steam will drive a turbine and produce electricity.
- Energy economics: General Fusion claims MTF is straightforward to manufacture and scale because it uses simple electromagnets and does not require expensive lasers.
Superheated plasma is the key to achieving fusion energy (Source: General Fusion)
When, not if
“Fusion is closer than you think,” Brister argues. General Fusion’s demonstration plant in the U.K. will seek to confirm that performance and economics of its MTF technology. “In this way we can scale it to a commercial pilot plant,” he added. To do this, we will create fusion conditions in a power plant-relevant environment without producing power. The [demonstrator] will create neutrons, and the data it creates will provide the information we need to build a commercial pilot plant that generates electricity.”
General Fusion then plans to design and build a commercial pilot plant, with construction scheduled to begin in 2022. The power plant could be operational by 2025. “We will take [lessons from the demonstration] to create the commercial pilot plant that will” generate power. “With the urgency of climate change in mind, we are on course to power homes, businesses and industry with fusion energy by the 2030s,” Brister predicted.