Amid an escalating crisis, the power source offers a dream — or a pipe dream — of limitless clean energy. From a report: Let’s say that you’ve devoted your entire adult life to developing a carbon-free way to power a household for a year on the fuel of a single glass of water, and that you’ve had moments, even years, when you were pretty sure you would succeed. Let’s say also that you’re not crazy. This is a reasonable description of many of the physicists working in the field of nuclear fusion. In order to reach this goal, they had to find a way to heat matter to temperatures hotter than the center of the sun, so hot that atoms essentially melt into a cloud of charged particles known as plasma; they did that. They had to conceive of and build containers that could hold those plasmas; they did that, too, by making “bottles” out of strong magnetic fields. When those magnetic bottles leaked — because, as one scientist explained, trying to contain plasma in a magnetic bottle is like trying to wrap a jelly in twine — they had to devise further ingenious solutions, and, again and again, they did. Over decades, in the pursuit of nuclear fusion, scientists and engineers built giant metal doughnuts and Gehryesque twisted coils, they “pinched” plasmas with lasers, and they constructed fusion devices in garages. For thirty-six years, they have been planning and building an experimental fusion device in Provence. And yet commercially viable nuclear-fusion energy has always remained just a bit farther on. As the White Queen, in “Through the Looking Glass,” said to Alice, it is never jam today, it is always jam tomorrow. The accelerating climate crisis makes fusion’s elusiveness more than cutely maddening. Solar energy gets more efficient and affordable each year, but it’s not continuously available, and it still relies on gas power plants for distribution. The same is true for wind power. Conventional nuclear power has extremely well-known disadvantages. Carbon capture, which is like a toothbrush for the sky, is compelling, but after you capture a teraton or two of carbon there’s nowhere to put it. All these tools figure extensively in decarbonization plans laid out by groups like the Intergovernmental Panel on Climate Change, but, according to those plans, even when combined with one another the tools are insufficient. Fusion remains the great clean-energy dream — or, depending on whom you ask, pipe dream. Fusion, theoretically, has no scarcity issues; our planet has enough of fusion’s primary fuels, heavy hydrogen and lithium, which are found in seawater, to last thirty million years. Fusion requires no major advances in batteries, it would be available on demand, it wouldn’t cause the next Fukushima, and it wouldn’t be too pricey — if only we could figure out all the “details.” (A joke I heard is that fusion operates according to the law of the “conservation of difficulty”: when one problem is solved, a new one of equal difficulty emerges to take its place.) The details are tremendously complex, and the people who work to figure them out have for years been dealing with their own scarcities — scarcities of funding and scarcities of faith. Fusion, as of now, has no place in the Green New Deal. In 1976, the U.S. Energy Research and Development Administration published a study predicting how quickly nuclear fusion could become a reality, depending on how much money was invested in the field. For around nine billion a year in today’s dollars — described as the “Maximum Effective Effort” — it projected reaching fusion energy by 1990. The scale descended to about a billion dollars a year, which the study projected would lead to “Fusion Never.” “And that’s about what’s been spent,” the British physicist Steven Cowley told me. “Pretty close to the maximum amount you could spend in order to never get there.” Read more of this story at Slashdot.