Learn how we’re building a star on Earth.
A free, open guide to plasma and fusion energy: learning resources, the commercial fusion industry, and the major training programs around the world.
²H + ³H → ⁴He + n + 17.6 MeV
Where would you like to start?
Newcomer, student, teacher, or heading into the field: there is a place to begin here.
Start from zero
No physics background needed. Short videos and explainers that cover the basics.
Study from advanced courses
Free university courses, textbooks and lecture notes from MIT, Princeton and others.
Play & experiment
Drive a virtual tokamak and try real plasma simulators in your browser.
Explore the industry
The companies working to commercialize fusion, grouped by approach and country.
Find a program
Plasma and fusion degrees and research groups across 40+ countries.
Tour the big machines
ITER, NIF, W7-X, KSTAR and other major fusion experiments.
What is fusion energy?
Stars make light and heat by fusing light atomic nuclei (like hydrogen) into heavier ones, releasing large amounts of energy. To do it on Earth we heat a gas above 100 million degrees until it becomes a plasma, the fourth state of matter, and hold it long enough for fusion to occur. Done well, a cup of fuel can supply a lifetime of electricity, with no carbon emissions and no long-lived waste. The science is proven; the work now is to make it practical and affordable.
Watch the explainers →Why fusion?
Three reasons it draws so much effort and investment.
Powerful
Gram for gram, fusion fuel releases millions of times more energy than coal, oil or gas, and it can run around the clock alongside wind and solar.
Safe
No meltdown risk and no long-lived waste. Stop the precise conditions and the reaction stops. There are no carbon emissions or air pollution, and the main byproduct is helium.
Plentiful
The fuel comes from water and other abundant elements. A bathtub of water and a little lithium hold enough energy for one person’s lifetime.
Framing adapted from U.S. Fusion Energy, a public resource on fusion in the United States.
Three good videos to begin with
Nuclear Fusion in 5 Levels of Difficulty
WIRED · Prof. Anne White (MIT)
A fusion scientist explains the same idea to a child, a teen, a college student, a grad student and an expert. A great place to start.
Fusion Power Explained – Future or Failure
Kurzgesagt – In a Nutshell
An animated overview of how fusion works, with an honest look at whether it can power the world.
ITER in Five Minutes
ITER Organization (official)
A quick tour of the world’s largest fusion experiment and the idea behind magnetic confinement.
Fusion energy FAQ
Common questions, answered in plain language.
What is fusion energy?
Fusion energy is the power released when light atomic nuclei, such as the hydrogen isotopes deuterium and tritium, are fused into heavier ones. The reaction D + T → helium + a neutron releases about 17.6 MeV. It produces no carbon emissions and no long-lived radioactive waste, and its main product is helium.
Is fusion energy real, and does it actually work?
Yes. Fusion powers the Sun and stars, and has been produced on Earth for decades. In 2022 the U.S. National Ignition Facility achieved ignition (net energy gain from the fuel), and the JET tokamak set fusion energy records. The remaining challenge is engineering power plants that are practical and affordable, which is the focus of today’s public and private fusion programs.
How can I start learning fusion for free?
Begin with short video explainers that assume no physics, then move on to free university courses and lectures from MIT, Princeton and others, interactive in-browser tokamak simulators, and well-regarded textbooks. They are all sorted by level on the Learn page of this site.
What jobs and careers exist in fusion energy?
Fusion needs physicists and a wide range of engineers (mechanical, electrical, materials, cryogenic, nuclear and software), plus technicians, project managers and more. Estimates suggest the sector may need roughly 25,000 to 60,000 workers by 2035.
What are the main approaches to fusion?
There are two broad families. Magnetic confinement uses powerful magnets to hold a hot plasma (tokamaks, stellarators, mirrors and field-reversed configurations). Inertial confinement rapidly compresses fuel using lasers or pulsed power. Companies and labs are pursuing many variations of each.