Why electrolysers are a big deal in today’s world

With green hydrogen being catapulted into the centre of a road map for a net-zero future, electrolyser technologies have in recent years gained more interest than ever since commercial electrolysis first started in the early 1900s. A concerted global effort in building electrolyser plants of 105 GW capacity would help meet the 1.5⁰C Climate Goal.

The EU has committed to installing a 40 GW capacity of electrolyser plants by 2030, with France’s planned capacity of 6.5 GW being the biggest in the territory.

Green Hydrogen from Electrolysis

Only 0.1% of global dedicated hydrogen production today comes from water electrolysis. Using renewables as the source of energy for the electrolysis process results in green hydrogen. Plunging renewable power costs and better electrolyser technologies has fanned the interest for green or electrolytic hydrogen. In fact, renewable electricity cost, especially PV or solar, has declined dramatically by 82% in the last decade.

The wider use of green hydrogen could vastly alter the carbon footprint for the hard-to-decarbonize sectors like steel, transport, and chemicals. Canada has become a front runner here for it has the world’s largest electrolysis plant – Bécancour (Canada) of 200 MW – that produces up to 8.2 tonnes of green H2 per day.

What’s next on the EU’s green hydrogen dreams? We have covered it extensively, here

A hydrogen strategy is not just about scalable production, a widespread network that transports hydrogen from the production site to the consumption site is crucial. 85% of hydrogen doesn’t move at all in Europe. It’s consumed right where it’s made. The European Hydrogen backbone aims for a network of 11,600 kms of hydrogen-ready pipelines by 2030 and 39,700 kms by 2040 – 69% of which would be converted natural gas pipelines.

It’s a win-win with electrolysis as it doesn’t release any greenhouse gas and its major output, hydrogen, is zero emissions. The only emissions associated with the process other than the electricity used, is the construction of the facilities. As global economies aim for a carbon-neutral future, the role of electrolyser plants is clear. There are a few factors stopping a massive scale-up.

Impediments in scaling up of electrolyser plants

The cost of setting up electrolyser plants is still the most prohibitive factor. Probably the reason why green hydrogen is still 2-3 times more expensive than fossil-based hydrogen. Though renewable sources provide low-cost electricity, it doesn’t solely determine the cost of production of green hydrogen. 

The investment cost for setting up an electrolysis facility is not small. For the EU’s targeted green hydrogen electrolysers, there is an estimated cost of €5–9bn for each 6GW capacity.

In order to reduce cost and improve the performance of the electrolyser electrolysers needs to be:

  • More Efficient: They need to consume less electricity which would ultimately result in lesser production costs.
  • More Durable
  • Simpler design: So that it is easier and less costly to set up and find materials.

We have summarized the trade-offs between efficiency, durability and cost of the electrolysers, below.

Types of electrolyser plants

Of the four main electrolyser technologies, Alkaline (ALK) electrolyser technology has been the mainstay so far. The Proton exchange membrane (PEM) electrolysers are commercially viable and have found a market foothold, as they have a smaller footprint. Solid oxide and anion exchange membrane (AEM), which are technologies mostly used in Europe, have high potential but are much less mature technologies. Only a few companies are involved in manufacturing them commercially. ALK and PEM work well at high temperatures.

Many prominent companies are debating on which type of electrolyser to vouch for. We are listing down some advantages and disadvantages of ALK and PEM electrolysers as noted by the industry experts.

ALK Electrolysers

Pros:

  • Well-established technology
  • non-noble catalysts
  • Long term Stability (almost twice as long)
  • Relatively low cost
  • Stacks in the MW range

Cons:

  • Low current densities
  • Crossover of gases
  • Low partial load range
  • Low dynamics
  • Low operational pressure
  • Corrosive liquid electrolyte

The technology behind PEM electrolyser plants is gaining ground. That the average capital expenditure (CAPEX) has been lower for ALK electrolyser plants than for PEM electrolyser plants on a per kilowatt basis hasn’t deterred the early adopters. In fact, the CAPEX for PEM has been dropping significantly.

Pros:

  • High Current densities
  • Or the ability to supply hydrogen to their clients while still being able to provide ancillary service.
  • High Voltage efficiency
  • Good Partial load range,
  • Systems can go through minimal power consumption.
  • Rapid system response
  • Compact system design
  • High Gas purity
  • dynamic operation

Cons:

  • High cost of components
  • Acidic corrosive environment
  • Possibly low durability
  • Insufficient data as it a less mature technology
  • Commercialization
  • Stacks below MW range

To ensure that low-cost green hydrogen isn’t just a pipeline project, a holistic approach is required, especially in terms of system design, deployment and operations. At the virtual conference – Electrolyser Plants & technologies on 19-20, October 2021 – our expert panel will discuss infrastructure developments for large-scale production of green hydrogen, and the commercial outlook of the projects in Europe.