The stock of energy by Hydrogen: a promising field
The development of renewable energies is such that the energy mix is deeply modified. The consumption is always increasing, and the demand has to be satisfied by the production, which is heavily changing. Consequently, solutions are implemented to compensate the intermittence of renewable energies.
Many plans and guidelines are implemented to reduce greenhouse gases caused by energy production, at different scales: Paris Agreement – global –; Clean Energy Package – European –; Energy transition for Green growth Act – France. All of them define quantitative goals to hit on several horizons. They all aim to promote the development of renewable energies, such as wind and PV plants. They produce clean energy and their installation barely impact the environment. Their main problem is their intermittence. Indeed, each of them is only productive when the weather is respectively windy or sunny, which rarely matches the consumption needs. The solution would be to find a way to stock electricity, which is not that simple. Several solutions exist, such as water stock within dams – providing the biggest quantity of electricity and used to match demand during consumption peaks – or batteries – more adapted to little quantities.
One of the most promising solution is electrochemical stocking by hydrogen. Production of hydrogen by water electrolysis only requires water and electricity. The molecule H2O is separated in two parts, clean oxygen can be released, and hydrogen is a gas that can be injected in gas network or stocked. Then this gas can be retransformed in electricity through a fuel cell. If the electricity used as an input has been produced by renewable sources, hydrogen is decarbonated and a clean energetic vector.
In addition to be a clean way to stock energy, it is a developing economic field that could provide many jobs, and it is already a subject studied by many people. For instance, Hydrogen Europe is an association which groups more than 100 actors: industrials, research organizations, national associations. The industrial actors are involved in many different sectors of activities: automobile, production and energy supply, electric and gas network managers. They aim to cluster their knowledges, their ideas and their innovations in order to structure the field to make it competitive and mature.
The most interesting ways to use hydrogen are mobility or in auto production and auto consumption systems. Hydrogen cars are quickly developing, as well as common transportation. These vehicles are supplied with hydrogen, which is transformed in electricity through a fuel cell within the car. Their autonomy is similar to a gasoline-powered car as well as the charging time, whereas an electric car has a low autonomy and needs a few hours to be loaded. However, their deployment is slow, as the cars are very expensive, and it should be preceded by a massive development of filling stations. Concerning auto production, some complete systems have been implemented, mainly for consumption centres which are not connected to the main network. Theses systems are composed with solar panels, electrolyser and fuel cells. The overproduction is stocked and reused when needed.
These systems are economically and technically mature, and they are essential to support the energetic transition, from big production centres to smaller units of production providing energy in a close area, in the global approach of short circuits.