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High Renewables in France - it can be done

At present France gets around 109 TWh of its electrical power from around 53GW of renewables and it is aiming to treble that to 300TWh by 2030, while also reducing the share of nuclear in electricity generation, which currently supplies around 382TWh, so that its share falls from 70% to 50% by 2035. There are also debates as to whether to phase out nuclear power entirely in France. So it is good that in a timely new study the International Energy Agency and French transmission system operator RTE have looked at whether it is technically possible to integrate very high shares of renewables in large power systems like that in France. 

The report notes that ‘advocates for 100% renewables claim - with reason - that past alarmist predictions of operational problems from increasing renewables in the power sector have been proven wrong’. Indeed, it says that it’s technically viable, with renewables supplying 85-90% of power by 2050 or 100% by 2060, subject to some key system upgrade requirements.

The first and most obvious is system balancing to deal with variable supply. The report says that ‘coping with the variability of energy produced from wind and solar PV is the main challenge for integrating renewables in power systems’. However, it says that ‘system adequacy i.e. the ability of a power system to cope with load at all times, can be ensured even in a system mainly based on variable renewables such as wind and solar PV, when substantial sources of flexibility are available, including demand-response, large-scale storage, peak generation units, and well developed transmission networks and interconnections’. 

The report looks to the use of new ‘dispatchable’ peaking units, small continuously available gas turbines which could increasingly use low carbon/green hydrogen or biogas as fuel, and large-scale, dedicated storage facilities, such as ‘batteries to address daily fluctuations; new or revamped pumped-hydroelectric generation units to address weekly variations; or synthetic fuels production (power-to-hydrogen or power-to-gas) and storage to address inter-seasonal and inter-annual variability’.

In terms of demand-side flexibility, it says that installations in buildings and factories would need to be able to respond automatically to market triggers or explicit requests from grid operators, while strengthened power grids, would enable large-scale geographical power system integration to mitigate local variations and facilitate access to flexibility sources. That would require substantial grid development efforts at both transmission & distribution levels. 

A less obvious requirement is the need for extra measures to maintain system stability- given reduced system inertia of the sort that was previously provided by the large rotating turbo-generators in coal and nuclear plants.  Wind generators offer some rotational inertia, but not much, PV solar offer none. However, the report says that this may not be a major problem: ‘there is a general scientific consensus that there are technological solutions to maintaining power system strength, and hence system stability, without conventional generation’.  Although it notes that specific issues are expected in the case of systems with a significant share of distributed solar, it says there are ways to provide virtual/synthetic inertia electronically, via green power convertor/inverters and storage systems, and also, on a larger scale, by so called synchronous condenser units, which are already widely used for ensuring system stability, with large unpowered flywheel like generators spun up store angular momentum using grid power. 

So, given the right mix of support technology, grid systems can run with very high renewable input. The report notes that assessing the costs of this ‘is beyond the scope of this report.’ But it says the costs may be substantial and ‘has deeper technical and social implications’. Even so it’s a good start, suggesting that it can be done. It is perhaps worth noting that the cost of providing replacement nuclear plants, enough to sustain a 50% share, would be very high- most of the French nuclear fleet was built in the 1970s and will soon been obsolete. The experience with its first replacement plant, the EPR at Flamanville, has been very sobering. On the current much delayed schedule, it looks like it will be 12 years late and, at €12.4 billion, almost four times over-budget. And that’s before the latest problems.  By comparison, renewables do seem to be proving more reliable and faster to deploy.  

What next? 

The French government recently published a new energy and climate law and the National Low-Carbon Strategy (Stratégie nationale bas-carbone, or SNBC). As the IEA/RTE report noted, the SNBC relies on three pillars: energy efficiency (reducing final consumption by almost half, from 1 600 TWh to 900 TWh), more use of biomass (from 200 TWh to 430 TWh by 2050), and a more significant role for (decarbonised) electricity as a final fuel, which must go from 25% to 50% of final energy needs by 2050. But the SNBC does not specify which kind of decarbonised electricity should be used.  Interestingly, as the IEA/RTE note, it does not foresee the use of fossil fuels associated with carbon capture, utilisation and storage (CCUS) for continued power production. So that leaves renewables and nuclear power as the two main possible options.

Under the current plan around 14 nuclear reactors may be closed by 2035, but President Macron has made clear his support for nuclear. The Élysée Palace issued a statement on Macron's 3 key nuclear convictions: ‘Our energy & ecological future depends on nuclear power; our economic and industrial future depends on nuclear power; and France's strategic future depends on nuclear power’. 

Given that it has seen itself as a nuclear pioneer, it would certainly be a shock for France to abandon nuclear, and the economics of the alternative programme does need careful assessment, but as Le Figaro newspaper noted, the IEA/RTE report does in effect indicate that ‘France could technically do without nuclear by 2050’. Whether it could and will do that and go for renewables instead remains to be seen. Progress on wind and PV solar has been relatively slow so far compared to some other European countries.  However the potential is certainly there- an earlier study put the technical potential for renewables in France at over 2000 TWh p.a. – about four times current  power consumption. As a next step, RTE is to publish a full assessment of different electricity scenarios to reach carbon neutrality. With EDFs finances in a perilous state due to its new nuclear plant construction disasters, and the looming high cost of old (and new) reactor repairs, it will be interesting to see what emerges. 

The potential for renewables in France is vast, with off shore wind still in its infancy, and, oddly, the use of solar hardly developed as yet. There may be land-use conflicts in some rural area, but, as I explore in my next post, Agro-solar opportunities are emerging that avoid conflicts with farming and may actually offer local ecological and productivity gains. 


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