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14 December 2022

CPH2 is out to capitalize on its membrane free cryogenic electrolyzer

CPH2, a UK based electrolyzer manufacturer, claims to have figured out a superior electrolysis technology to the popular PEM (Proton Exchange Membrane), Alkaline and SOC (Solid Oxide Cell) alternatives, based around a membrane free concept coupled with cryogenic gas separation. Rethink had the chance to sit down with its Business Development Manager, Qamar Khan, at Enlit Europe 2022 in Frankfurt and explore its technology and business case.

Formed in Ireland in 2012 by Dr Nigel Williamson and Joe Scott, CPH2 believes that it has found a way to deliver a truly green electrolysis technology which doesn’t rely on rare Earth metals such as Palladium or Platinum for membranes or powerful catalysts.

CPH2’s electrolyzer is capable of taking in filtered tap water without the need of separating the hydrogen-oxygen bonds at the membrane stage. Instead, water is mixed with the electrolyte and travels to the stack where a mixed gas is generated. Up until this point it works very much like an Alkaline electrolyzer, but such technologies use porous diaphragms to separate the resulting elements, which introduce ohmic resistances decreasing the overall efficiency of the system. Instead, CPH2 takes the mixed gas, dries it, and then cryogenically separates it in a patented system, producing purified hydrogen and medically pure oxygen – up to 99.999% purity for both hydrogen and oxygen. The UK company uses liquid nitrogen to achieve such cryogenic temperatures but claims that the opex (operating cost) won’t be affected by the need to replenish the coolant as its operating lifespan is longer than a year.

CPH2 also claims that due to the absence of the membrane, the electrolyzer is simple to build, operate and maintain and because it is constructed from readily available materials – without the usage of platinum group metals or expensive polymer membranes – the stack components are more than 98% recyclable or reusable.

Another benefit of a membrane free design is that there is no reject water, so the world’s oceans won’t get contaminated with brine concentrated water. It also doesn’t need the water to be as pure as PEM or Alkaline technologies require. Water contamination will predominantly be an issue in the Middle East since such countries don’t have much access to fresh water, yet many plans for electrolyzer gigafactories have made public. Rethink covered Oman’s $140 billion plans in a previous issue – more details can be accessed here.

Growing concerns over the effects that reject water from electrolysis will have on the local fauna and flora have been expressed by many before, which ultimately motivates other companies to keep innovating in an attempt to find a sustainable technology, in the true sense of the word.

Electrolyzers are definitely not a case of one size fits all since the market is wide enough for multiple technologies to thrive based on their advantages. Alkaline electrolysis has got a slight edge on PEM at the moment – mostly due to the capex (initial investment). Due to the reliance of PEM on expensive catalysts and membrane materials, it sits just over Alkaline prices. In the US the price of green hydrogen from Alkaline electrolysis sits at $3.35/kg while for PEM the price is slightly higher at $4.39/kg. Same story goes for Western Australia and The Netherlands: $2.78/kg compared to $3.85 and $16.04/kg compared to $19.05/kg respectively.