For decades, nuclear fusion was dismissed with a familiar punchline: it would always be 30 years away. However, a rapid succession of breakthroughs over the past five years — driven by privatization, the AI boom's energy demands, and sustained investment — has shifted the outlook, placing fusion energy on what researchers now describe as a realistic and achievable timeline.

Widely regarded as the "holy grail" of clean energy, nuclear fusion holds the potential to deliver virtually limitless power with zero greenhouse gas emissions and minimal environmental side effects, positioning it as a comprehensive solution to the world's energy trilemma.

"To power one person's lifetime, it's a bathtub of seawater and a laptop battery's size of lithium," nuclear physicist Annie Kritcher told Fortune. "It's not a lot of materials, and there's no [long-term] radioactive waste like we have with fission."

The first major milestone was reached at California's Lawrence Livermore National Laboratory in late 2022, when a team led by Kritcher achieved what many had considered improbable: first ignition, a man-made fusion reaction that produced more energy than it consumed — the first time in history such a result had been obtained. Since then, the achievement has been replicated, and additional advances have accumulated across fusion research programs worldwide.

These breakthroughs span a range of technological approaches. The Lawrence Livermore success relied on high-powered lasers, while other leading candidates employ tokamaks — devices that use extraordinarily powerful magnets to confine plasma. China's tokamak-based EAST reactor, often referred to as an "artificial sun," is currently on track to achieve ignition by 2027, which would make it the first fusion reactor to sustain plasma without external heating. Yet another avenue involves z-pinch systems, which use electrical currents to compress plasma.

Despite abundant proof that fusion is scientifically achievable and replicable across multiple technologies, the question of scalability remains unresolved. Nuclear fusion is not currently anywhere near commercial viability, and the resources required to generate even small quantities of energy remain enormous and impractical for real-world deployment. That gap between a laboratory result and a power plant that can operate within an energy market is now the central hurdle for the field.

A new framework developed by researchers at the Massachusetts Institute of Technology (MIT) aims to address this challenge directly, charting a path from laboratory achievement to industrial and economic reality. The framework evaluates "the physical inputs needed to sustain controlled fusion energy production, as well as the cost of building power plants that can compete in energy markets," according to a recent MIT press release.

The researchers contend that the exploratory phase — testing disparate methods and materials — has effectively concluded. The scientific feasibility of fusion is established, and the focus must now shift to rigorous economic analysis.

"It's all the things that come along with finding, allocating, and spending money at this scale," said Dennis Whyte, a professor of nuclear science and engineering at MIT and co-author of the study, published last month in the Journal of Fusion Energy. "This is critical to what we do. We should look at the economics. If we want this technology to actually be meaningful in the world economy, we have to start getting straight with ourselves about these topics."

A key attribute of the framework is its applicability across all fusion energy approaches currently under development. At this early stage of fusion research, it remains uncertain whether tokamaks, laser-controlled inertial confinement, or z-pinch systems will ultimately prove most viable for commercial deployment. MIT's framework could help clarify which path offers the greatest economic promise.

Whyte describes the framework as "completely agnostic to whatever fusion concept you use, because the physical reality of fusion is that you expend money to build the capability to produce fusion power." Co-author Andrew W. Lo underscores the fundamental economic principle at stake: "It doesn't matter whether the fusion power plant is small or large, the bottom line is: In both cases you better have money coming out that exceeds the money going in, otherwise it's not going to be around for very long."