In France, the level of intermittent renewable penetration remains modest: in spite of abundant renewable potential, French politicians have decided to rely primarily on nuclear energy, which benefits from decades of investment and experience, and allows today for very competitive energy prices.


Whereas the electricity consumption has remained stable at around 500 TWh  p.a. since 2004, peak load power has been increasing, from 80 GW in 2004 to 102,1 GW in 2012  mainly due to electrical heating. According to the French transmission grid operator RTE, the temperature sensitivity of the load, defined as the extra generation needed when the outside temperature decreases by one Celsius degree in the winter (with a mirror definition in the summer), reached 2 300 MW per °C in the winter in 2011 . The yearly peak demand, defined as the highest in-state electricity demand within a year, has sustained a permanent increase over the past years, as shown in figure 1.


Evolution of the higest peak demand in France over the past years  GW



Figure 1 – Evolution of the highest peak demand in France over the past years.


Temperature sensitivity could attain 2500 MW per °C by 2025 . This trend is expected to last: the development of heat pumps, air conditioning and electric vehicles are surging the peak load. An illustration is proposed on figure 2.


Figure 2 – Forecast of peak power in RTE’s reference project scenario.


In winter 2012, the French electric grid was under high stress: Western Europe faced a great cold wave between February 1st and 13th. Whereas French electricity Sport prices (EPX) reached 1938 €/MWh on February 9th at 10h, the prices in the neighboring countries remained reasonable. On February 7th and 8th, 7350 and 7845 MW of interconnection capacity were used to compensate the lack of capacity, especially by importing from the UK and Germany  . This event clearly shows the French lack of capacity, which could be avoided with storage assets able to run a few hours a year and to bring the needed capacity. Furthermore, the regions Bretagne and Provence Alpes Côte d’Azur (PACA) were stressed because of congestions: such regions are generating much less energy than they are consuming (see figure 3).


Figure 3 – Context for storage in France.