How does nuclear fusion work, and why is the US investing in it?

In December 2022, scientists at the Lawrence Livermore National Laboratory in California achieved a breakthrough in nuclear fusion. For the first time, they successfully created more energy from a fusion reaction than the energy used to start the process.

This was the latest of several developments in the past few years that have brought nuclear fusion closer to becoming a viable source of energy.

In 2022, the Biden administration and the Office of Science and Technology Policy set a goal of having fusion energy on the grid by the early 2030s. While it is still far from becoming a commercial fuel source, fusion’s advantages mean that scientists and governments around the world are continuing to invest in the technology.

What is nuclear fusion and how does it work?

Fusion is the atomic reaction that powers the sun. It involves fusing two atoms together at an extremely high temperature and pressure, releasing energy in the process. However, creating those conditions for fusion on Earth is difficult. For a fusion energy system to be viable, it must produce more energy through fusion reactions than the energy needed to produce the reaction. Those reactions are maintained in a plasma, a state of matter that scientists are still working to understand.

Nuclear fusion differs from nuclear power currently generated in reactors, which occurs through fission. Fission is when heavier elements split into lighter elements.

What are the advantages and challenges of nuclear fusion?

If scientists find a way to sustain fusion and harness its energy, it has significant advantages over current fuel sources.

Fusion power is a clean energy source. It produces no greenhouse gases, uses relatively common materials for fuel, and does not pose the risk of a nuclear meltdown (unlike current nuclear reactors). Also, it does not produce long-lasting radioactive waste the way current nuclear reactors do, which can be challenging to dispose safely.

Fusion energy is still a developing area of research, and figuring out the science is just the first step—the cost competitiveness and commercial viability are still open questions. The costs of commercial fusion power are still unknown, as they’ll be impacted by unknown maintenance costs, advancements in materials that can hold plasma, and undetermined regulatory costs. Projections for fusion energy on the grid range from 10 to over 20 years.

Where is the US currently at in developing nuclear fusion?

Recent years have brought scientists closer to usable fusion energy. In 2021, scientists at the Massachusetts Institute of Technology developed high-temperature superconducting magnets, which could reduce the cost of fusion energy systems. European scientists in 2021 set a record for sustained energy output from fusion. And in 2022, fusion ignition (generating net positive energy from a fusion reaction) was achieved at the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory.

Government funding plays a critical role in supporting the research and development of fusion energy. The Department of Energy (DOE) has consistently invested in fusion research, with funding levels increasing over time.

While the DOE’s Office of Science is the largest funder of fusion research, the field also receives some federal funding from the National Nuclear Security Agency (a semi-autonomous DOE agency) as well as the Department of Defense. This funding goes toward government labs, such as the efforts at the NIF, as well as universities and private industry.

Private funding has also increased over the past few years. A 2022 survey of fusion companies reported $117 million in government funding and $4.7 billion in private funding for fusion companies, marking a $2.8 billion increase in private funding since 2021.

Continued government and private sector support represent a long-term investment in a source of clean and abundant energy.

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