Nuclear Energy
A gram of uranium holds as much energy as a tonne of coal. Hardly any technology promises so much and frightens so deeply.
Nuclear energy is the great point of contention among the energy sources. For some it is a clean climate saviour, for others uncontrollable devil's work. Rarely do fascination and fear lie so close together. That is exactly why a particularly cool head pays off here, for hardly any topic is so overlaid with feelings, symbols and old camp battles.
Where the energy comes from
The stuff of which stars are made is also in the atomic nuclei around us. There are two ways to tap it. In nuclear fission one breaks apart heavy atomic nuclei like uranium, whereby enormous heat is released. In nuclear fusion, conversely, light nuclei like hydrogen merge, that is the process that makes the sun shine. All of today's nuclear power plants use fission; fusion is to this day not practically usable, although it has been researched for decades.
A bit of history
Nuclear fission was discovered in 1938 in Berlin by Otto Hahn and Lise Meitner, and its first application was terrible: the atomic bomb of 1945. From this military origin comes part of the fear that still has aftereffects today. In the 1950s civilian use began under the slogan "Atoms for Peace," and for a few decades nuclear power was regarded as the energy of the future, clean, cheap, limitless. Two names ended this euphoria: Chernobyl in 1986 and Fukushima in 2011. Germany drew the consequence from this and switched off its last reactors in 2023, while other countries like France continue to rely heavily on nuclear power.1
How a reactor works
At its core a nuclear power plant is astonishingly old-fashioned: it is a very elaborate way of boiling water. Nuclear fission generates heat, the heat makes steam, the steam drives a turbine, and that produces electricity, exactly as in a coal-fired power plant, only without a chimney and without CO₂. The difference lies in the fuel and in what it leaves behind.
Advantages
The strengths are real and should not be talked down. Nuclear power delivers electricity reliably around the clock, independent of weather and time of day, and is thus suited as base load. In operation it emits hardly any CO₂, so it is far better for the climate than coal or gas. And it is incredibly energy-dense: a tiny amount of fuel replaces mountains of coal, which means little space and little transport.
Disadvantages and dangers
But the flip side weighs heavily. First, the radioactive waste: it radiates for tens of thousands of years and must be safely stored for that long, longer than any human civilization has existed so far. To this day there is not a single permanently operating final repository anywhere in the world. We are pushing this problem onto future generations.
Second, the accident risk: severe accidents are rare, true, but when something goes wrong, a whole region can become uninhabitable for decades, as Chernobyl and Fukushima showed. Third, the costs and the duration: new reactors are extremely expensive and often take fifteen to twenty years to complete, time that is scarce in the fight against the climate crisis. And fourth, the connection to the bomb: whoever can enrich uranium comes dangerously close to a nuclear weapon, which is why nuclear technology is always also a question of war and peace.
The critical look
On hardly any topic does independent thinking pay off as much as here, for both camps work with oversimplifications. The proponents like to talk only about the climate and stay silent about waste, costs and repositories. The opponents often conjure a picture of catastrophe that overstates the real but statistically rare risks, while they barely mention the deaths from coal-fired electricity, which occur year after year in far greater number.
An honest judgment holds both: nuclear power is neither the end of the world nor the miracle solution. It is a technology with real advantages and real, in part very long-term, burdens. Whoever wants to have a say therefore asks concretely: what does the electricity really cost when construction, dismantling and final storage are counted in? Who is liable in an emergency? And who bears the burden of the waste, we or our great-great-grandchildren? For behind the seemingly purely technical question lies a deeply moral one: what risks may we take whose consequences will be borne only by people not yet born?