Summary – An op-ed written in June for Alternatives Economiques that took a while to be published. In it I discuss the past and future constraints on our power system (the “adequacy” question), the well-known loss-of-load criterion, and the recent note from the French nuclear safety authority (ASN), which somewhat shakes up the subject.
Introduction
As the update of the French multi-annual energy programme (PPE) approaches, thinking about the future of our energy system is in full swing. The urgency of that reflection is heightened by recent events: first the gas crisis, which we may not yet have fully come through, and the stress corrosion problem that affected part of our nuclear fleet last winter — or, more generally, the repeated strains on the winter peak in recent years.
Current events should not, however, obscure the deeper reasons that push us to transform our energy system. On the one hand, we must now begin the progressive electrification of our end uses for the sake of decarbonisation. On the other hand, we must anticipate the end of life of the historical nuclear fleet, which will have ceased operating by 2060 at the latest. Those were, incidentally, the two main motivations for the work of the transmission system operator RTE in its “energy futures” study published almost two years ago (see the presentation here).
On the legislative side, the work around the green industry bill currently being drafted has made it possible to reaffirm that long-term visibility and competitiveness of electricity prices are essential, and that the only structural solution is the development of low-carbon generation capacity.
These electrification questions are also at the heart of our transport policies, with the ongoing deployment of electric vehicles, as well as of heating questions. Banning gas boilers in renovation is now one of the issues raised in a consultation open until the end of July.
Decarbonisation strategy
The more our decarbonisation strategy is refined, the better we understand the scale of the electrification ahead. That is why RTE’s recent analysis tends to revise our electricity consumption upwards for 2035.
RTE points out that there are several levers for managing this growth. Two of them concern reducing overall energy demand: on one side changing our consumption habits (heating to no more than 19 °C, avoiding heating or cooling an unoccupied building, preferring a video call to a long trip, driving more slowly on the motorway, etc.) and on the other improving the efficiency of our systems.
The other two levers are directed at low-carbon electricity generation: developing new capacity, and maintaining and optimising our historical nuclear fleet.
In the long term, one obviously thinks of the urgency of launching the construction of six or eight EPR2 reactors so that the first are connected around 2040. Doing so will require overcoming the difficulties we experienced building the Flamanville plant and finding a financing solution. But these EPR2s will represent barely more than 10% of our electricity needs, and in the shorter term only renewables will be connected to the grid.
What should worry us, in the light of RTE’s analyses, is that not only is the current ambition for renewables — as set out for instance in the President’s speech in Belfort or in a working note from the General Secretariat for Ecological Planning ahead of the future PPE — insufficient, but on top of that we are not meeting the European targets in this area.
Covering our needs
The subject on the table today is “adequacy”, in other words the answer to the question “will we have enough electricity to cover our needs?”
It can seem fairly easy to settle this question after the fact: note that the great fear of last winter ended up translating into a high cost of electricity, a bit of sufficiency (chosen or imposed) and above all a great deal of imports from neighbouring countries, whereas we had been a net exporter for more than 25 years. But we now have to anticipate and think about the situation in 2030. So we must try to forecast the volumes we will consume and set against them the volumes we will produce.
What is specific to electricity is that this balance question also has to be posed on much shorter timescales — in relation to a cold spell or a windless period, for example — and we must be prepared for that. If there is not enough generation, some customers have to be shed (cut off), and the power system is organised so that this load shedding is as painless as possible, despite the false information that circulated on this subject last winter. Moreover, load shedding is common and has nothing to do with a blackout, which is a serious problem in which the entire system collapses.
Rationally, a well-sized system should let us cope with uncertainty without too much load shedding — but not with every eventuality. We must prepare for difficult weather of the kind seen every ten or twenty years, for the loss of a nuclear plant or of an interconnection with a country, and so on. It would simply be absurd to claim to be able to face the loss of our entire fleet painlessly.
Thomas Veyrenc, director of foresight at RTE, describes very well the difficulty of communicating about this loss-of-load criterion, since their role as balance responsible party always makes them look too cautious when nothing happens and never cautious enough when a problem arises. He also recalls that this criterion is set by regulation. By 2025 the system has ample margin, but in the medium term plant closures in neighbouring countries and the electrification of end uses could put us in difficulty.
The current nuclear fleet
On 13 June the French nuclear safety authority (ASN) published an opinion that attracted much comment, stating that at this stage we have no guarantee of being able to extend the historical nuclear plants to 60 years. That uncertainty weighs on our adequacy problem for 2035 and even more for the years that follow.
There is also a passage in that opinion which has been little discussed, yet is heavy with consequences and, at the very least, worth debating. The ASN suggests that from now on, when sizing the power system, we should consider a new eventuality — the one we experienced last winter, which led to the shutdown of a large number of plants: the possibility of a generic defect across the nuclear fleet. Should our system therefore prepare not merely to operate with one reactor fewer, but with a third of the nuclear fleet missing?
Should we then analyse the risk of this being combined with a windless period, or with a drought that would make operating the remaining reactors harder? The consequences of this ASN suggestion — which at this stage looks more like an invitation to debate than an actual decision — will have to be carefully analysed. Depending on how the hazards are accounted for, the impact on the sizing and cost of the power system will no doubt be significant.
The reach of this opinion could extend beyond the historical nuclear fleet. Much effort has gone into identifying who might be responsible for our current difficulties, and one may regret political decisions such as the closure of Fessenheim or the cancellation of the Astrid programme. But it must be acknowledged that, fundamentally, part of the problems we face stems from the fact that we built a standardised fleet very quickly. That inevitably generated a trough after the 2000s which, following Fukushima, probably stretched out somewhat too long and contributed to a loss of skills in the nuclear industry as many engineers and technicians retired. It also played a role in the scale that the stress corrosion episode reached last winter.
Building around fifty nuclear reactors in series over a very short period had important advantages that should not be forgotten, but as we start a new programme it will be worth remembering the problems it can cause.