Cartlidge, E. July 11, 2017. Fusion energy pushed back beyond 2050. BBC.

We will have to wait until the second half of the century for fusion reactors to start generating electricity, experts have announced.

A new version of a European “road map” lays out the technological hurdles to be overcome if the processes powering the Sun are to be harnessed on Earth.  The original 2012 version of the road map forecast that a demonstration fusion power plant could be operating in the early 2040s, in order to supply electricity to the grid by 2050. But now the demonstration will be delayed until 2054 caused largely by delays to ITER, a 20 billion Euro reactor being built in the south of France to prove that fusion energy is scientifically and technically feasible.

In fact, according to EUROfusion’s programme manager, nuclear physicist Tony Donné, DEMO’s schedule could slip further, depending on progress both with ITER and a facility to test materials for fusion power plants that has yet to be built.

“2054 is optimistic,” he says.

Fusion involves heating nuclei of light atoms – usually isotopes of hydrogen – to temperatures many times higher than that at the center of the Sun so that they can overcome their mutual repulsion and join together to form a heavier nucleus, giving off huge amounts of energy in the process.  In principle, this energy could provide low-carbon “baseload” electricity to the grid using very plentiful raw materials and generating relatively short-lived nuclear waste. But achieving fusion in the laboratory is a daunting task.

Doughnut-shaped reactors known as tokamaks use enormous magnetic fields to hold a hot plasma of nuclei and their dissociated electrons in place for long enough and at a high enough density to permit fusion.

ITER represents the culmination of 60 years of research. The world’s largest ever tokamak, it will weigh 23,000 tonnes and is designed to generate 10 times the power that it consumes.  But the project has been beset by delays and cost overruns. Originally foreseen to switch on in 2016 and cost around 5 billion Euros, its price has since roughly quadrupled and its start-up pushed back to 2025. Full-scale experiments are now not foreseen until at least 2035.

ITER is also complex politically, an international project with 7 partners: China, the European Union, India, Japan, South Korea, Russia and the United States. As host, Europe is paying the biggest share of the costs – about 45%.

The roadmap sees ITER as the single most important project in realizing fusion but not one that is designed to generate electricity.

DEMO, a tokamak adapted from the ITER design

This will also cost billions of euros, and is intended to produce several hundred megawatts of electricity for the grid. To do so, it must run continuously for hours, days or ideally years at a time, as opposed to ITER, which will operate in bursts lasting just a few minutes.  DEMO will also have to generate its own supply of tritium (the radioactive isotope of hydrogen which can help drive fusion) by using neutrons it produces to transform lithium (its other hydrogen isotope, deuterium, can instead be extracted from sea water).

Researchers are already starting to develop conceptual designs for DEMO. But because they need results from ITER to draw up a detailed engineering design, their progress is vulnerable to any further delays in France.

Federici argues it is vital to demonstrate electricity generation from fusion “not too far after the middle of the century”. Otherwise, he says, there may no longer be a nuclear industry able to build the commercial fusion plants that would follow, and the public may lose patience.  The subsequent loss of political support, he wrote in the DEMO design report, “would run the risk of delaying fusion electricity well into the 22nd century.”