"Renewable energies have already won", for the boss of Voltalia

For Sébastien Clerc, to date, "renewables are a bet more than won", thanks to the collapse of costs.

"Today the purchaser of electricity who commits to a 10-20 year contract, whether he is an electricity distributor, company, State... chooses 95% of renewables because it is the cheapest energy almost everywhere", says the boss of this French company, a rare company with a listed mission, present in Latin America, Africa, Europe.

Sébastien Clerc sees at least 20 years of global growth without major obstacles for the sector.

Investors are scrambling. And the subject of the square is not really one, he says: "To meet world electricity needs, covering the equivalent of Aquitaine with photovoltaic panels is enough".

He does not deny the disputes. "Because the installations can be seen. It's the Nimby phenomenon (not in my backyard), not in my garden."

Wind energy is the focus of criticism at this stage. Nothing says that this will not be the case tomorrow for solar power, whose fields of 30 or even 100 hectares will eventually see each other, he notes. "The oppositions will eventually arrive."

French President Emmanuel Macron, who wants to push solar power, has asked for "a fair balance" between ground and rooftop installations.

Except that putting on the roofs is more expensive, it is less effective (panels not necessarily ideally oriented, not mobile), notes the director of Voltalia.

"Today we still act as if we had a choice," he adds. But in the face of global warming and the need to green energy, "in the end, we will do everything we can. "And there will be plenty of renewables, everywhere in the world", he assures.

Preparing for windless nights

For him, it is above all the continuation of the adventure, in 20 years, which carries the great unknowns, when renewables will have reached a critical part: how will we manage at night in the absence of wind?

"Today renewable energies are advancing on their own, and it is our job, developers, industrialists, to make it happen as well as possible. But at a certain point, let's say beyond 50% market share, the governments will have their part to play. For example, helping to assume the additional cost of battery storage, when neither gas nor coal will no longer be there to serve as a "buffer".

A first answer, "still under the radar", is that we will have to adapt the time of our consumption, insists Sébastien Clerc.

For example, running hot water tanks when it is sunny and/or windy. Ditto for heating, by raising the temperature at the right times to then store the heat in the room (which will require better insulated buildings). Modulate also the schedules of the industry.

What about large-scale storage? Today, power is stored mainly by "steps" ("stations for transferring energy by pumping", installed between two water reservoirs). A mature solution, but which supposes having mountains, notes Mr. Clerc.

For the moment more expensive, the batteries will have to take over, suggests the developer, also a player in storage, which also evokes hydrogen, but its lower yield.

"When I put 100 kWh to store energy with hydrogen, I recover around 30%. With the battery, I recover more than 80%, and around 90% with the step", he describes.

These subjects are not necessarily the most urgent for a country like France, which is largely nuclear-backed, he adds. But they are, for example, in Great Britain, launched in a vast renewable program to escape its dependence on gas: the country last year invested several billion euros in batteries.

"We have to think about all of this, put in research and development... It's a real conceptual problem: to approach 100% renewables, we don't yet know how to do it. But we will do it".