Is nuclear fusion the answer to the climate
crisis?
Promising new studies suggest the long elusive
technology may be capable of producing electricity for the grid by the end of
the decade
Oscar
Schwartz
Mon 28 Dec
2020 10.00 GMT
https://www.theguardian.com/environment/2020/dec/28/nuclear-fusion-power-climate-crisis
If all goes
as planned, the US will eliminate all greenhouse gas emissions from its
electricity sector by 2035 – an ambitious goal set by President-elect Joe
Biden, relying in large part on a sharp increase in wind and solar energy
generation. That plan may soon get a boost from nuclear fusion, a powerful
technology that until recently had seemed far out of reach.
Researchers
developing a nuclear fusion reactor that can generate more energy than it
consumes have shown in a series of recent papers that their design should work,
restoring optimism that this clean, limitless power source will help mitigate
the climate crisis.
While the
new reactor still remains in early development, scientists hope it will be able
to start producing electricity by the end of the decade. Martin Greenwald, one
of the project’s senior scientists, said a key motivation for the ambitious
timeline is meeting energy requirements in a warming world. “Fusion seems like
one of the possible solutions to get ourselves out of our impending climate
disaster,” he said.
Nuclear
fusion, the physical process that powers our sun, occurs when atoms are pushed
together at extremely high temperatures and pressure, causing them to release tremendous
amounts of energy by merging into heavier atoms.
Since it
was first discovered last century, scientists have sought to harness fusion, an
extremely dense form of power whose fuel – hydrogen isotopes – are abundant and
replenishable. Moreover, fusion produces no greenhouse gases or carbon, and
unlike fission nuclear reactors, carries no risk of meltdown.
Fusion seems like one of the possible solutions to get
ourselves out of our impending climate disaster
Martin Greenwald
Harnessing
this form of nuclear power, though, has proven extremely difficult, requiring
heating a soup of subatomic particles, called plasma, to hundreds of millions
of degrees – far too hot for any material container to withstand. To work
around this, scientists developed a donut-shaped chamber with a strong magnetic
field running through it, called a tokamak, which suspends the plasma in place.
MIT
scientists and a spinoff company, Commonwealth Fusion Systems, began designing
the new reactor, which is more compact than its predecessors, in early 2018,
and will start construction in the first half of next year. If their timeline
goes as planned, the reactor, called Sparc, will be capable of producing
electricity for the grid by 2030, according to researchers and company officials.
This would be far faster than existing major fusion power initiatives.
Existing
reactor designs are too large and expensive to realistically generate
electricity for consumers. Through the use of cutting-edge, ultra-strong
magnets, the team at MIT and Commonwealth Fusion hope to make a tokamak reactor
that is compact, efficient and scalable. “What we’ve really done is combine an
existing science with new material to open up vast new possibilities,”
Greenwald said
Having
demonstrated that the Sparc device can theoretically produce more energy than
it requires to run in the research papers published in September, the next step
involves building the reactor, followed by a pilot plant that will generate
electricity onto the grid.
Scientists
and entrepreneurs have long made promises about fusion being just around the
corner, only to encounter insurmountable problems. This has created reluctance
to invest in it, particularly as wind, solar and other renewables — although
less powerful than fusion — have become more efficient and cost effective.
But the
tide is changing. In Biden’s $2tn plan, he named advanced nuclear technologies
as part of the decarbonization strategy, the first time the Democrats have
endorsed nuclear energy since 1972. There is also significant investment coming
from private sources, including some major oil and gas companies, who see
fusion as a better long term pivot than wind and solar.
According
to Bob Mumgaard, chief executive of Commonwealth Fusion, the aim is not to use
fusion to replace solar and wind, but to supplement them. “There are things
that will be hard to do with only renewables, industrial scale things, like
powering large cities or manufacturing,” he said. “This is where fusion can
come in.”
The plasma
science community is generally enthusiastic about Sparc’s progress, though some
question the ambitious timeline, given engineering and regulatory hurdles.
Daniel
Jassby, who worked as a research scientist at the Princeton Plasma Physics Lab
for 25 years, is skeptical about whether a fusion reactor like SPARC will ever
provide a feasible alternative source of energy. Tritium, one of the hydrogen
isotopes that will be used as fuel by Sparc, is not naturally occurring and
will need to be produced, he said.
The team at
MIT propose that this substance will be regenerated continuously by the fusion
reaction itself. But Jassby believes that this will require a huge amount of
electricity, which will make the reactor prohibitively expensive. “When you
consider we get solar and wind energy for free, to rely on fusion reaction
would be foolish,” he said.
Mumgaard
concedes that the challenges that lie ahead are daunting. But he remains
confident.
“There is a
broader trend in acknowledging how important climate is and that we need all
hands on deck,” he said. “We got into this problem with technology, but with
fusion there are big opportunities to solve this with technology.”
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