May 12, 2026 
Carl Hirndrehe Series: Part 2 of 4: What Is Burning in There — and Why Not Already?
Wars over oil. Gas-price subsidies. LNG terminals built at emergency speed. Dependence on governments that can close a valve and occupy entire economies with the consequences.
For decades, energy policy has revolved around one question: who controls the fossil fuels? It is a reasonable question. It is not a law of nature. We have simply grown used to energy policy meaning the administration of scarcity.
What if scarcity did not have the final word?
Not in a hundred years, and not as science fiction. As a technological possibility that already exists, that is being developed around the world, and that is still treated politically as something we can deal with later. The subject is nuclear fusion.
Before the familiar objections arrive: fusion is not fission. It is neither Chernobyl nor Fukushima in different packaging. It is the process that powers the Sun. Whether it can produce reliable and affordable electricity on Earth remains open. That open question now deserves much more seriousness than it receives.
A laboratory in Greifswald
In May 2025, the Wendelstein 7-X stellarator operated by the Max Planck Institute for Plasma Physics reached an important milestone. It held the so-called triple product — a measure combining plasma temperature, density, and confinement time — at a high level for 43 seconds. The plasma reached about 30 million degrees, with an energy turnover of 1.8 gigajoules.
This is not power-plant operation. Wendelstein 7-X does not generate electricity for the grid and is not intended to. Its purpose is to test whether the stellarator is a viable basis for a future fusion plant. The record therefore does not prove that the energy transition will now arrive from Greifswald. It shows that a difficult part of the physics and engineering is progressing. That is less spectacular than a finished plant, and precisely for that reason important.
The Max Planck Institute describes the Wendelstein 7-X result as a record for long plasma durations. It also notes that unpublished JET data could change the way the record is ranked. Science is occasionally less photogenic than a press release. A world record with a footnote is still a world record with significance.
A calculation, not a promise
One can make fusion’s scale visible with a thought experiment. If today’s global electricity generation were replaced entirely by plants rated at one gigawatt each, the result would be roughly 3,400 plants. That is a model calculation, not a construction plan.
The fuel requirement would be surprisingly small compared with the fossil economy. Deuterium, a heavy isotope of hydrogen, occurs in seawater. Tritium would have to be bred from lithium inside a future reactor. Helium would be produced as a by-product. ITER explains the fuel cycle in more detail — and states the crucial limitation at the same time: tritium is scarce today. A closed fuel cycle is not a side issue. It is a prerequisite.
The orders of magnitude still make the difference visible. A rough calculation for the imagined fleet comes to about 34,000 cubic metres of seawater per day, 11,600 tonnes of lithium per year, and roughly 700 tonnes of helium as a by-product. These numbers depend on reactor design, efficiency, and capacity factor. They should be read as a comparison, not as an exact forecast: fusion would be a high-energy, low-mass system. Fossil energy is a mass-throughput system.
The fossil economy moves enormous quantities of fuel every year. That comparison is not only ecological. It changes the political logic. A plant supplied with fuel from seawater depends less on shipping routes, producing countries, and strategic reserves. In exchange, it depends much more on materials, maintenance, and tritium infrastructure. Every solution shifts the problems. The question is whether the new problems would be more manageable than the old ones.
Why is so little happening?
Technical difficulty is one answer. It is not the whole answer.
The old reflex
In Germany, “nuclear” is a warning signal for many people. That is historically understandable. Fission has risks, long-lived waste, and a political history that cannot simply be talked away.
But it does not follow that fusion and fission are the same. A fusion reactor has no self-sustaining chain reaction and no meltdown in the classic sense. If the required conditions disappear, the plasma cools and fusion stops. There are still radioactive tritium, neutron exposure, and activated materials. Fusion is not risk-free. Its risks and waste questions are different.
The failure to explain that distinction is political. A well-informed rejection would be legitimate. A rejection based on an equation of unlike technologies is not.
Four years against four decades
A minister can approve solar panels on a school roof today and cut a ribbon in two years. A tritium facility or a new materials-testing infrastructure requires planning, permits, and construction. The result may be visible in ten years. By then, the minister will almost certainly have moved on.
That is not a moral defect in individual politicians. It is an incentive structure. Democracies are good at responding to visible short-term problems. They are much worse at keeping projects stable across several election cycles. Fusion is an inconvenient technology for a politics that likes to photograph results before the next election.
Money and interests
Oil and gas form a global market worth trillions. No one needs to sabotage fusion in a secret room. It is enough for attention, infrastructure, and political energy to keep flowing into existing systems.
The renewable industry also has legitimate interests and its own funding structures. Solar and wind are indispensable for the coming decades because they can cut emissions quickly. That does not mean they will replace every later technology. Focusing research on one destination confuses a necessary bridge with the entire road.
What would it cost?
The often-cited estimate of five to ten billion euros over 15 years is neither an official budget nor a guaranteed price. It is a political scenario: more money for Wendelstein 7-X and materials research, industrial production of high-temperature superconductors, tritium infrastructure, and demonstration plants.
Whether the sum is enough depends on what it is expected to deliver. It may be too low for a proven commercial plant. It is a plausible order of magnitude for a coordinated European research and industrialisation programme.
Germany has spent many billions in recent years on energy expansion, crisis measures, and fossil transition infrastructure. The federal government has announced more than two billion euros for fusion during the current legislative period in its fusion action plan. That is a step. It is not yet a guarantee that the money will reach the bottlenecks quickly enough.
The question is therefore not whether fusion will solve the energy problem tomorrow. It will not. The question is whether we can afford to investigate a possible long-term energy source so hesitantly that inaction begins to look like a neutral choice.
It is not neutral. Inaction means continuing to write off fossil infrastructure, accepting existing dependencies, and potentially buying later the technology that is still being developed in Europe today.
What comes next
Part 2 looks at the physics: what happens inside a fusion reactor, why there are tokamaks and stellarators, and why the more complicated stellarator might be the simpler machine to operate.
Part 3 takes apart the remaining components — superconductors, materials, divertors, heat extraction, and above all the tritium breeding blanket. Part 4 asks why the greatest obstacle may not be the reactor but our political calendars.
The physics has advanced far enough to justify a political decision. The raw materials exist. What is missing is not certainty that fusion will succeed. What is missing is the willingness to pursue an open possibility seriously.
