Invention slashes hydrogen electrolyser costs

Hydrogen electrolysers could become over 90 per cent cheaper to build, the inventors of a new device claim

Surrey-based RE Hydrogen has developed a 1KW version of its electrolyser, which uses electricity to separate water into hydrogen and oxygen, and this month received £25,000 from the Technology Strategy Board (TSB) to produce a bigger unit.

The dramatic cost-cutting was achieved by eliminating mechanical parts not related to the electrolysis reaction using a different manufacturing process, RE director Dr Amitava Roy told The Engineer.

‘Our manufacturing cost is 93 per cent lower than the current state of the art, based on what we have already done. Mass production could save another 25-50 per cent,’ he said.

So far RE has developed 50W, 150W and 1KW versions of the device for use in laboratories and for the bottled hydrogen market. A 5KW model is on the way thanks to the TSB, but the firm also intends to build 100KW units that can be used for industrial hydrogen production and energy harvesting.

Roy hopes the device’s low costs would make it useful for the energy industry to capture and store intermittent sources of electricity such as wind, as well as aiding power management for the national grid and for individual smart home systems.

Although it would be up to the customer to decide what source of electricity they used to produce the hydrogen, one advantage of RE’s device is its ability to capture relatively low energy output from unpredictable sources such as small wind turbines.

According to Roy’s calculations, a year’s worth of electricity from a 1.5KW wind turbine would be worth £670 under the current feed-in tariff rate, but the hydrogen that electricity could create with RE’s electrolyser would be worth around £4,000.

Electrolysers work by passing an electric current through water, effectively breaking it down and causing hydrogen and oxygen to form at the cathode and anode, respectively.

RE’s device is also designed to prevent the potassium hydroxide (KOH) used as an electrolyte from leaking. The KOH is much cheaper than alternative technology such as proton exchange membranes, which require costly platinum electrodes.

‘A common problem in the industry is leaks and KOH is quite nasty because it’s corrosive,’ said Roy. ’But we are all carrying it in our pockets in mobile phone batteries and it is not a problem. So we’re taking the kind of approach the battery industry has taken to seal in the KOH.’