[ industry trends ]
Electrolysers: AEC, AEM, PEM and SOE for hydrogen( and syngas) production
© 2021 sbh4 GmbH
Notes:
– In the AEC, AEM and PEM, lye or water flow from the electrolyser cell with the oxygen and / or hydrogen gases. These liquids are mixed and recirculated to the electrolyser.
– Air is used to purge the SOE anode to avoid oxygen accumulation which may present a hazard at the high operating temperature.
– Bipolar plates made of stainless steel( titanium for PEM) are used to stack adjacent cells in each electrolyser type.
O2 H2 O2 H2 O2 H2
30 % KOH( aq) Anode
Diaphragm Cathode
Anode
Membrane Cathode
Anode Membrane
Cathode
Air plus O2
OH – OH – H +
O 2 –
30 % KOH( aq)
H2O as water
1 % KOH( aq)
H2O as water
H2O as water
Air
Anode Electrolyte Cathode
H2( plus CO)
H2O as steam( plus CO 2
)
|
Alkaline Electrolysis Cell AEC |
Anion Exchange Membrane / Alkaline Electrolyte Membrane AEM |
Polymer Electrolyte Membrane / Proton Exchange Membrane PEM / PEMEC |
Solid Oxide Electrolysis Cell SOE / SOEC |
|
Electrode material
Electrolyte
Energy source
Current density Hydrogen or syngas product Gas outlet pressure Cell temperature
|
– Cathode: Ni, Co or Fe – Anode: Ni
Lye: 25- 30 % Potassium Hydroxide solution in water 100 % electrical power
Up to 0.5 A / cm 2 Hydrogen
Up to 40 bar ~ 80 ° C
|
– Cathode: Ni / Ni alloys – Anode: Fe, Ni, Co oxides
Anion Exchange ionomer( e. g. AS-4) 100 % electrical power
0.2 – 1 A / cm 2 Hydrogen
Up to 35 bar H2, 1 bar O2 ~ 60 ° C
|
– Cathode: Pt / Pd – Anode: IrO 2
/ RuO 2
Fluoropolymer ionomer( eg Nafion, a DuPont brand) 100 % electrical power
Up to 3 A / cm 2 Hydrogen
Up to 40 bar ~ 60 ° C
|
– Cathode: Ni – Anode: La / Sr / MnO( LSM) or La / Sr / Co / FeO( LSCF) Zirconium Oxide with ~ 8 % Yttrium Oxide ~ 25 % heat from steam, ~ 75 % electrical power Up to 0.5 A / cm 2 Hydrogen( or syngas if fed with steam and CO 2
) Close to atmospheric ~ 750 to 850 ° C
|
The cash crunch
Start-ups rarely buy other rival start-ups. Cultural differences, potential power struggles, and a lack of cash are obstacles to this incestuous form of consolidation.
Smaller players are more likely to be consumed by cash-rich players. Those leaning on helpful parent companies, which have diversified revenue streams and deep wallets( e. g., Fortescue Zero, Siemens Energy, thyssenkrupp nucera), will have the upper hand as M & A deals come onto the table, or start-ups see that a white-knight offering a rescue package is the only way forward.
A relevant example is the investment that Longi made in HydrogenPro in 2024. Longi is an established solar panel producer with a credible product, strong cash flow, and a profitable business model. Longi recently diversified into electrolyser production in China and has grown rapidly. In 2023, it provided 80 MW of alkaline electrolysers to Sinopec’ s 260-MW Kuqa facility.
Longi’ s gravitas in the renewable energy space means it can afford to invest for the long term without the need for an acquired business to demonstrate synergy overnight.
Doubling down
Strategic investors with a history of smart involvement in this space have the opportunity to both use electrolysers and benefit from selling them to third parties. They may choose to double down on some of their favourite investments and bring them in-house. For example, Mitsubishi Heavy Industries joined Longi and Andritz in Hydrogen Pro’ s recent investment round.
Chart Industries, Larsen and Toubro, and McPhy have a three-way agreement. McPhy brings the electrolyser technology, Larsen and Toubro is a leading Indian EPC house with access to extensive manufacturing facilities, and Chart seeks to future-proof its business model with access to clean tech that will support decarbonisation across multiple sectors. Will McPhy end up in the portfolio of one of these two larger actors?
18 Hydrogen Tech World | Issue 21 | April 2025