Fusion can deliver a potentially limitless supply of energy. It produces no greenhouse gasses and it is intrinsically safe; no chain reactions occur in the reactor. Moreover, there are no problems associated with the longer-term repository of radioactive waste.
Dr Francesco Romanelli
Last week, the European Fusion Development Agreement (EFDA)
published a roadmap outlining measures that will be necessary in order to deliver fusion electricity to the grid by the middle of this century. The Roadmap to the realisation of fusion energy
divides this journey into eight interconnected missions. For each mission, the document assesses the landscape of related research as it presently stands, and prescribes courses of action that will facilitate progress.
The ability to produce fusion energy in an efficient manner could deliver profound benefits both to European member states and to governments across the globe. Whilst policymakers remain committed to cultivating a portfolio of sustainable energy resources, fusion electricity has several unique advantages. Firstly, as fusion methods use the abundant raw materials deuterium and lithium to produce electricity, they could be employed to deliver a potentially limitless supply of energy. Secondly, this process does not release any greenhouse gases into the atmosphere, and it produces no long-lived radioactive waste. Finally, fusion is safer than fission in the sense that chain reactions do not take place.
Essentially, fusion energy offers the potential to deliver a limitless supply of clean, safe electricity. Unfortunately, the key word here is ‘potential’. To date, scientists have not been able to create a net surplus of fusion power; fusion systems are not yet capable of generating outputs that are greater than their inputs. However, this might not be the case for too much longer. The international experiment ITER
– formerly known as the International Thermonuclear Experimental Reactor – is due to commence operations in 2020, and participating scientists are confident that they will be able to produce an output of 500MW from a 50MW input.
To find out more about the role that European scientists are playing in the realisation of efficient fusion electricity, I spoke to EFDA Leader Dr Francesco Romanelli. I began by asking him to expand on the advantages of fusion power.
"Fusion can deliver a potentially limitless supply of energy," Dr Romanelli explained. "It produces no greenhouse gasses and it is intrinsically safe; no chain reactions occur in the reactor. Moreover, there are no problems associated with the longer-term repository of radioactive waste. According to our analyses, waste would not need to be stored for more than 100 years after the closure of a fusion power plant; radioactivity decays within decades. Whatever is left can be recycled within a new reactor. The point is that with nuclear fission, you have to deal with waste products from the primary reaction. Long-lived isotopes are produced. With fusion, however, the primary reaction doesn’t produce any
Whilst this sounds ideal in theory, the realisation of efficient fusion energy generation is far from simple. I asked Dr Romanelli to outline some of the most significant obstacles that researchers will have to overcome in order to produce a net surplus of energy from fusion generation methods.
"This is the overarching goal of ITER," he replied. "In order to generate fusion electricity, we have to confine reactants at a temperature 20 times greater than that of the sun. This is actually something that we have already been able to achieve. For example, in 1997, the Joint European Torus (JET)
project produced roughly 16MW of fusion power from an input of only 25MW. We are close to the point of breaking even.
"With ITER, we plan to produce 10 times more energy than we input into the system," Dr Romanelli continued. "We have to inject a lot of power into the machine to keep the gases of the reactants at high temperatures. This power balances the heat losses that take place from the centre of the plasma to the periphery. Both our theoretical understanding and experimental evidence suggest that heat losses rise, at most, linearly as the radius of the machine increases. However, the amount of fusion power that we can produce does
increase in line with plasma volume. This means that in order to achieve a net energy gain, we must build a much larger device. For this reason, the dimensions of the system at ITER will be twice as large as those of JET. ITER is currently being constructed in France. We plan to have the first of its systems operational in 2020, and I think that by the end of that decade, ITER will have succeeded in generating a net surplus of energy from fusion."
In addition to its assessment of the state and trajectory of fusion-related research, the EFDA roadmap emphasises the need to seek collaborative opportunities both with industrial partners and with non-European nations. I asked Dr Romanelli how industrial and international involvement will help Europe to meet its fusion energy targets.
"Clearly, when the time comes to create a commercial reactor, industry will have to take the lead," he replied. "ITER will be followed by a demonstration power plant named DEMO
, and this will be the only step between our preparatory research and the creation of a commercial fusion plant. For this reason, DEMO cannot be defined and designed by researchers alone. We need to have input from associated industries. Commercial partners should be involved to the extent that after DEMO has proven successful, they will take over all
"We also need fusion energy to remain interesting from an economic perspective," Dr Romanelli continued. "In other words, we need to ensure that the capital cost of a fusion plant is low enough to attract the required investment. This can only be achieved by involving industry at an early stage in development. What are the best practices in terms of fabrication and maintenance? If we are to meet our 2050 deadline, we must be able to manufacture materials on an industrial scale. In the roadmap that we have recently completed at the request of the European Commission
, we set out our strategy for international collaboration. We need to take advantage of every opportunity. Not every facility should be built in Europe. Wherever possible, we must share the burden of development."
Finally, I asked Dr Romanelli whether he is happy with the progress that is being made by Europe’s fusion research community. Are we on course to deliver efficient fusion energy to the grid by the middle of this century?
"We remain fully committed to the delivery of ITER within specification, cost and schedule," he answered. "Our first priority is to meet the goals outlined in Horizon 2020
. Robust preparations will be necessary in order to exploit ITER’s maximum potential. JET has a major role to play in this respect as it is currently operating as a small-scale ITER; it is using the same fuel and materials. It therefore offers the ideal environment in which to develop technologies and prepare for the ITER operation. If we encounter a problem today using JET, we have time to find a solution before ITER begins its operations. If we weren’t using JET, we might not identify that problem for another decade and the project would be significantly delayed. In my opinion, our preparatory activities are essential. The valuable lessons that we learn at this stage reduce the risk associated with ITER and increase the likelihood of swift exploitation further down the line.
"The fusion roadmap has been adopted by our supervisory committees as a guide for future activities," Dr Romanelli concluded. "We must now implement the roadmap’s recommendations, starting with the goals of Horizon 2020. With sufficient support from participating member states and the European Commission, I am confident that we can achieve our 2050 target."