Ergosup (€16 for directly producing highly pressurized hydrogen in refueling stations for hydrogen e-drones and e-bikes)

Ergosup, a French cleantech startup founded in 2012, develops and commercializes solutions for the production and storage of green hydrogen using its own patented electrolysis technology. The company has developed HyRiS products, which are green hydrogen refueling stations for hydrogen e-drones and e-bikes, as well as a low-cost hydrogen supply solution for laboratories and small industries.

Challenges: hydrogen fuel

Hydrogen is the cleanest and most efficient energy-generating fuel, making it particularly useful for applications involving automobiles, ships, and aircraft. The use of hydrogen in the context of clean transportation requires the ability to store hydrogen at high pressures ranging from 200 to 700 bar in tanks on board transportation.

Currently hydrogen production is dominated by the steam reforming of natural gas due to its low cost. However, steam reforming releases carbon dioxide. The electrolysis of water with electrolyzers can produce green hydrogen if their power source is coupled to the renewable energy sources. Currently, the hydrogen pressures at the outlet of the electrolyzer do not exceed 80 bar, which is a minimum to be reached in order for large-scale applications in the field of transportation to be conceivable. The conventional method involves compressing the gas with a mechanical compressor, which is costly and requires frequent maintenance.

Hydrogen may be produced at large industrial plants, compressed, and then transported to distribution stations, or may be produced directly at the distribution station. Logistics-wise, on-site production is particularly advantageous.

It would be interesting from an ecological standpoint if this hydrogen production were conducted locally and centrally by electrolysis, without further compression by mechanical compressor.

Ergosup Technology

Ergosup develops electrolyzers that directly produce very highly pressurized hydrogen (over 80 bar) in a decoupled manner.

Ergosup electrolyzer

The electrolyzers typically consist of a high-pressure chamber containing an anode and a cathode that are immersed in an electrolyte. The gas outlet pipe of the high-pressure chamber is divided into a pipe for discharging gaseous hydrogen and a pipe for discharging gaseous oxygen. Each pipe is equipped with a valve—the hydrogen valve and oxygen valve, respectively—allowing for the independent extraction of these two gasses from the chamber. In order to induce electrolysis, the anode and the cathode are connected to a DC generator, capable of supplying them with power.

Ergosup’s electrolyzer (ref. US20210123145A1).

The two electrodes are initially immersed in the electrolyte. The electrolyte consists of a pair of redox agents, M^m+/M, and a pair of depolarizing agents, A^a+/A. The oxygen valve is open, and the hydrogen valve is closed.

During the first step of electrolysis, the DC generator delivers a current (ranging between 400 and 2000 A/m²) for a period of time, which enables the efficient co-deposition of metal M (such as zinc) and depolarization additive A (such as iron) from M^m+ and A^a+, respectively, at the cathode. Materials of M and A are chosen to prevent the evolution of hydrogen during this step. Oxygen exits the chamber through the oxygen outlet pipe for which the oxygen valve is in the open position.

In the second step, the power supply is turned off and the local depolarization effects appear. The local depolarization effects form between A, M, and the H⁺ ions, thereby accelerating the dissolution of the metal M and the hydrogen evolution.

One of the key innovations in Ergosup’s electrolyzers is the depolarization additive formed by the redox pair (A^a+/A) in the electrolyte, which makes it possible to achieve the return to equilibrium, consequently, the hydrogen evolution without the use of a hydrogen electrode. The depolarization additive can regulate the kinetics through the concentrations of the ionic species A^a+ and M^m+ into the electrolyte.

The hydrogen leaving the chamber initially contains oxygen and hydrogen. This mixture is sent through an oxygen outlet pipe for which the oxygen valve is in the open position, while the hydrogen valve of the hydrogen outlet pipe is closed, at a capacity that permits dilution with another gas (argon for example). An oxygen sensor located in the oxygen outlet pipe makes it possible to measure the oxygen content in the gas in real time.

When oxygen is no longer present, the oxygen valve is closed. As the gas is generated, the pressure of the hydrogen produced in the chamber increases. When the desired pressure is reached, the hydrogen valve is opened and the hydrogen is sent to a storage tank through the hydrogen outlet pipe. A pressure sensor measures the pressure within the chamber.

The electrolyzer’s reported hydrogen evolution rate is 29 g/h/m², and it takes 1 h to produce 20 g of hydrogen at 80 bar.

In comparison to the state of the art in the production of hydrogen by electrochemical means, the resulting simplification and accompanying economic benefits of Ergosup’s electrolyzers present a significant technological advance for on-site production of high pressure hydrogen.

Ergosup Patent

FR3079529A1 ELECTROCHEMICAL PROCESS FOR THE PRODUCTION OF GASEOUS HYDROGEN UNDER PRESSURE BY ELECTROLYSIS AND BY DEPOLARIZATION
US20210123145A1 Electrochemical process for the production of pressurized gaseous hydrogen by electrolysis then depolarization
EP3775323A1 Electrochemical method for producing pressurised hydrogen gas by electrolysis and subsequent depolarisation
WO2019193280A1 Electrochemical method for producing pressurised hydrogen gas by electrolysis and subsequent depolarisation
JP2021520451A Electrochemical method for producing pressurized gaseous hydrogen by electrolysis and then depolarization

Ergosup Technology Applications

Ergosup’s target markets are the supply of hydrogen for industrial applications, hydrogen service stations, as well as stationary massive energy storage solutions.

Ergosup Products

Ergosup HRiS

They have developed the HyRiS Lab Product station (Hydrogen Refuelling Station), with a production capacity at 100 bars from 0.7 to 4 kg per week. They are developing a series of five new machines.