An engineer and doctor in electrochemistry, Patrick Paillère has always been interested in electrolysis. He worked at Péchiney and then Areva, before becoming President of Ergosup. This start-up, which is based in the Drôme department in France, develops new electrolyzer concepts with the aim of facilitating the production of decarbonized hydrogen. Describing himself as a “late startupper”, Patrick Paillère views the energy transition as an important challenge to be tackled.
The electrolysis of water is a long-established technique that was invented more than 100 years ago. The reaction involves passing an electric current through water, splitting it into hydrogen and oxygen, therefore producing both gases simultaneously.
We are working on a different concept, based on an electrolysis process that involves zinc salt. This enables the reaction to occur in two stages. Firstly, oxygen alone is released, then hydrogen is released in the second step.
The benefits are twofold. The first relates to pressure. Most hydrogen applications require storage under high pressure. This is particularly the case for mobility. However, conventional electrolyzes are difficult to control at high pressure. Oxygen and hydrogen are produced on both sides of a very thin membrane. They are attracted to each other and seek to recombine in liquid or gaseous forms. Our system makes it easy to release hydrogen directly under high pressure at 200 or 350 bar. Under these conditions it is possible to completely eliminate mechanical compression, or to only need one compression step to go up to 800 bars. The compressor is thus only operated under the most straightforward, and therefore the least costly, conditions.
“This solution enables users to maintain their usual level of flexibility in terms of power consumption.”
The second advantage is the ability to separate the moment when electricity is consumed from the moment when hydrogen is produced. This decoupling makes it possible to use electricity when it is inexpensive or when there is a surplus, and then to store the hydrogen in an intermediate form, and finally to start the second stage of the process at the point when the energy demand arises. A conventional electrolyzer produces hydrogen simultaneously with electricity consumption.
It is based on the acidification of the electrolyte. Hydrogen is preserved in the form of ions. In which form it is totally stable.
Virtually all hydrogen applications require the combination of production and storage under pressure. Our solution is valuable for powering any fuel cell system that converts hydrogen into electricity. It can be used for transport purposes of course, but also for fixed applications on isolated sites, such as powering cellular phone towers.
Hydrogen is also used by many industries. In this framework, we offer on-site production solutions to overcome logistics issues. We offer a hydrogen generator and associated storage. This solution enables users to maintain their usual level of flexibility in terms of power consumption.
“if everyone drove a battery electric vehicle, at certain times we would face periods of excessive power demand for recharging vehicles.”
Initially, we are focusing on applications where hydrogen provides strong added value, such as the supply of electricity to forklifts and drones. For example, a drone can carry about 100 to 150 grams of on-board hydrogen, compressed to 300 bars. Equipped with a light fuel cell, this process enables a four-fold increase in the drone’s range: increasing the flight time from 30 minutes to 2 hours. We have formed a partnership with Delair, a company that aims to use hydrogen to obtain 4 hour ranges.
We produce several families of generators with varying capacities. It all depends on the application! For example, the smallest ones produce about a kilo of hydrogen a day. They are the size of a large American refrigerator: two meters tall with a square meter footprint. They are especially designed for the drone market. We also design larger systems, from 20 kg/day to 350 bar in a 20-foot container.
Today, there are relatively few FCEVs on the roads due to the lack of infrastructure. It is therefore essential to provide a network across a territory to promote hydrogen mobility. Hydrogen is a great vector of decentralized energy! Which is why we want to provide an economical and easily deployable solution. We are working on an initial scale-up with stations of around forty kilos, before developing larger systems. We will eventually have larger stations, but I think this transitional period is necessary.
Indeed, if we only take energy efficiency into account, batteries perform better. However, the problem must be considered as a whole: if everyone drove a battery electric vehicle, at certain times we would face periods of excessive power demand for recharging vehicles. All model simulations highlight this fact. Even by replacing just 20% of the current fleet with BEVs would create a hugely increased power demand. To meet this demand it would be necessary to build new nuclear power plants.
“I don’t think that hydrogen and battery technologies should be regarded as opposing alternatives.”
Conversely, hydrogen, because it can be easily stored, enables this power demand to be smoothed out. This is a strong argument in favor of this system.
I totally agree with this view. When seeking to increase efficiency, the capex (or baseline costs) of facilities increases. However, we are currently seeing major falls in the cost of photovoltaics. Prices have dropped to below 20 euros per megawatt hour (MWh). At such prices the significance of the electrical costs, and therefore efficiency, is much lower.
In summary, we need low-cost facilities that can use electricity when it’s cheap, rather than high-efficiency facilities that require year-round operation to be financially profitable.
For me, hydrogen coupled with renewable energy is a key element of this transition. Unlike some people, I don’t think that hydrogen and battery technologies should be regarded as opposing alternatives. For some applications, such as day/night electricity storage, batteries are clearly a viable solution. But in many other fields, such as mobility or long-term storage, hydrogen is a key driver of the energy transition.