Path to Zero
Path to Zero
4.10 - Making Nuclear Fusion a Successful Power Source with Princeton’s Sir Steven Cowley

Fusion has held a great deal of promise for decades to potentially generate carbon-free electricity. Some leaders believe we are at turning point for fusion-powered energy.

Our guest is a theoretical physicist who is one the world’s leading authorities on fusion energy. Sir Steven Cowley is the Director of the Princeton Plasma Physics Laboratory, which is a U.S. Department of Energy national laboratory for plasma physics and nuclear fusion science.

“The good news is we’re getting very, very close,” says Cowley. “We can taste the end game and the end game is commercial fusion.”

About Sir Steven Cowley

Before assuming his current role at Princeton, Cowley was President of Corpus Christi College and professor of physics at the University of Oxford. He also served as chief executive officer of the United Kingdom Atomic Energy Authority and he was knighted by the Queen of England in 2018 for his role in fusion science.

“I’ve worked nearly my entire life on nuclear fusion and trying to make that successful power source for the planet,” says Cowley.

A computer-generated image of ultra-hot plasma with a doughnut-shaped fusion device known as a tokamak. Photo courtesy of Princeton Plasma Physics Laboratory (PPPL)

Cowley’s research has been funded by Science and Technology Facilities Council (STFC) and the Engineering and Physical Sciences Research Council (EPSRC). Cowley also co-chaired the National Academy of Sciences assessment of plasma science in the United States.

Fusion vs. Fission

Fission occurs when a neutron slams into a larger atom, forcing it to excite and split into two smaller atoms. Additional neutrons are also released that can initiate a chain reaction. When each atom splits, a tremendous amount of energy is released.

Uranium and plutonium are most commonly used for fission reactions in nuclear power reactors because they are easy to initiate and control. The energy released by fission in these reactors heats water into steam. The steam is used to spin a turbine to produce carbon-free electricity.

Fusion occurs when two atoms slam together to form a heavier atom, like when two hydrogen atoms fuse to form one helium atom. This is the same process that powers the sun and creates huge amounts of energy—several times greater than fission.

Fusion reactions have been studied for decades by scientists, but are difficult to sustain for long periods of time because of the tremendous amount of pressure and temperature needed to join the nuclei together.

Princeton Plasma Physics Laboratory (PPPL)

Cowley leads a team of researchers that is working to solve a grand scientific challenge of the 21st century – harnessing on Earth the fusion energy that drives the sun and stars to produce a safe, clean and virtually unlimited source of power for generating the world’s electricity.

Princeton Plasma Physics Laboratory Test Cell

PPPL is simultaneously leading advances in next-generation computing and microelectronics, and are forming partnerships with industries to accelerate the development of fusion energy.

According to Cowley, there has been at least $4 Billion in venture capital investment in fusion startups over the past few years.

“The plan is to get the first electricity from fusion in the 2030s and actually start delivering for the market,” Cowley tells Tucker. “I’ve often said that we’ve got to do fusion for a cost that the consumer wants to pay for electricity and that’s harder than just doing fusion.”