How should we plan for the future in the face of today’s energy problems?

 Caroline Mazzoleni: Year after year, we break records in terms of renewable energy production, with more and more solar and wind power assets being commissioned. The limit today is more often than not a lack of space and land. But renewable energy production can be further increased through a number of innovations, such as floating photovoltaics, the use of disused quarries, agrivoltaics (a combination of agricultural production and photovoltaic energy) and offshore wind power, in which Bouygues Construction has valuable expertise. However, in view of the fact that these energies are intermittent, we will increasingly be faced with the problem of finding outlets that are more diversified than those for primary energy production. What do we do at times of peak renewable energy production, such as in the summer when the sun is shining but energy demand is low? My vision is that we produce hydrogen close to the renewable energy production facility by electrolysis, so that it can be stored for later use or transported for use in industry or mobility.

 Speaking of mobility, what future vision do you hope to see in 2040 ?

C.M.: I think that mobility in 2040 will have entirely broken free of fossil fuels. In order to stop using oil, coal and gas and so reduce the carbon impact of mobility, we need to reconsider our modes of transport, develop soft mobility and use electric energy, from a carbon-free source. However, it can’t be imagined that everything will be based on battery electric vehicles: even if there is less travel, battery electric vehicles will be limited by the network infrastructure and the rapidly saturated charging capacity of the vehicles. In my view, battery electric is highly suitable for light vehicles, such as electrically assisted bicycles, scooters and cars, but much less so for heavy modes of transport. This is where hydrogen has a valuable contribution to make as a green energy storage tool: hydrogen-powered vehicles are electric, but the power source consists of a hydrogen tank that feeds a hydrogen fuel cell to power the electric motor. This hydrogen can be produced by electrolysis from water, close to where renewable energy is produced, as soon as surplus energy is available. It can also be transported at lower cost by reusing natural gas networks, which are given a second life, or using a dedicated logistics solution Without hydrogen, the surplus energy produced during production peaks would be lost, and the land dedicated to green energy would not be used to its full potential. Hydrogen is a vector of energy flexibility in a world based on renewable energy.

What do we have to do to reach our target in 2040?

C.M.: The first answer is to increase our renewable energy production capacity: the idea is not to disfigure our landscapes, so we must innovate to find the land we need. In addition, the production and use of hydrogen must be made more efficient. Today, we need 50 to 60 kWh of electricity to produce 1 kg of hydrogen, which in turn yields about 16 kWh with current fuel cells. The efficiency of electrolysis is around 70% and that of the hydrogen fuel cell around 50%. At this stage, it is interesting as a way of using electricity that would otherwise be lost, but less so if it is to replace other uses of electricity, which would involve less loss. Numerous research teams are therefore working on improving these efficiencies, particularly in France and in Europe. On top of this, there is an economic difficulty. As long as this technology is still emerging, the production cost of hydrogen remains high, like that of photovoltaic panels twenty years ago. Subsidies and public investment are needed to get the ball rolling, as with renewable energies.

Are we ready for these developments?

C.M.: At Bouygues Energies & Services, our technologies are already mature enough to be used on an industrial level. At the same time, there are already hydrogen-powered vehicles on the road: hydrogen mobility is well on track! Korean and Japanese carmakers are selling hydrogen-powered cars, some other manufacturers are starting to produce hydrogen-powered trucks, and a French player is already producing buses and coaches that run on hydrogen! All that is missing is an offer in our catalogue. I have no doubt that hydrogen will accelerate the energy transition. All the examples that we know of work! It is also a local economic vector for the territories. For example, some regions that produce renewable electricity through waste processing could transform this energy into hydrogen and then use it as a green fuel for waste collection vehicles. This is a virtuous loop, contributing to the circular economy, focusing on local ecosystems. We can take advantage of this opportunity to relocalise energy, avoid unnecessary transport, and create real territorial hubs.