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3 August 2022

AquaHydrex readies pilot stage of electrolyzer manufacturing

By Bogdan Avramuta

AquaHydrex, a decade-old Colorado based electrolysis designer, claims to have figured out a more effective way of producing green hydrogen. Although not many details have been made public at this point, the new electrolysis process has been designed from the ground up, more closely resembling an Alkaline electrolysis design, trying to avoid the high capex cost often associate with PEM electrolyzers. PEM electrolysis has always been hindered by the high cost of its catalyst, usually made from platinum or iridium, and by its acidic environment.

CEO Steve Kloos explained that PEM “puts too much dependence on the rarest metal in the Earth’s crust – Iridium, and relies on an overly sensitive membrane.” But as we said the design is from the ground up, and it opts for a highly conductive electrolyte for high performance and because such an electrolyte would result in a pure and drier gases, this minimizes balance of plant needs.

And Kloos said that the aim was to eliminate the analyte and catholyte plant loops and steel piping as well as gas separators in order to cut capex and corrosion as well as eliminating parasitic shunt currents which then allows the electrolyzer to by tied directly to renewables.

The AquaHydrex website features a video of Kloos explaining the company’s rationale for design which also cuts out the use of rectifiers, minimizes install time and therefore EPC costs and shortens the time from project start to gas generation. Another major design feature is removing the flowing electrolyte.

AquaHydrex appointed Kloos in 2019 when it was ready to start taking steps towards commercialization. Up until then the company was fully invested in the R&D phase and was burning slowly through its money. The company has now filed multiple patents on electrolyzer design and has passed a small-scale proof of concept and is ready to ramp production through its first pilot plant.

The aim is to collect as much data as possible in order to drive up the reliability of the product ready for the next stage, manufacture at scale.

Kloos argues that present day electrolysis requires high capital expenditure (Capex) and high operational expenditure (Opex). The Opex is by far the largest component contributing to the LCOH (levelized cost of hydrogen). This is due to the efficiency of the electrolysis process and the cost of the input renewable energy.

The company has also moved to using advanced power electronics and an advanced power architecture that is more efficient, lower cost and grid supporting.

The same design approach can also be used to directly make ammonia or combine it with CO2 to produce synthetic fuels.

In the past Alkaline designs have not proved capable of direct connection to renewable energy without a battery buffer, which typically adds yet more cost.

The Rethink Energy Annual Primary Electricity index has identified that hydrogen will eat up 29,163 TWh of electricity in production of 315 million tons of hydrogen a year by 2050 to replace existing hydrogen feedstocks for ammonia and oil refining as well as add supply lines for Steel and Cement manufacture; to power heavy transport and to provide power storage and also for home heating.

AquaHydrex patents describe its process as an electrochemical reactor, comprising with multiple gas diffusion electrodes with multiple layers, with an electrically conductive layer, which is gas permeable and a second layer which is liquid electrolyte permeable, made of porous conductive materials. This creates multiple layers or pockets of gas across multiple electrolyte spacers, in turn made of cheap nonconductive polymers. In this way it creates two separate streams of gas to exit the electrolyzer and deal entirely with cheaper materials.