Harnessing the power of electrolysers to supercharge green hydrogen production
Harnessing the power of electrolysers to supercharge green hydrogen production.
In spite of the hard push to promote hydrogen as a clean energy solution, it’s always had somewhat of a ‘bad side’. That’s because 98% of world production comes from fossil fuels, mostly grey hydrogen made from natural gas, resulting in carbon emissions comparable to all of Japan’s.
Where, you may well ask, is all that grey hydrogen being used? Well, around 100 megatons are used per year, roughly equivalent to the weight of 2 million elephants, and it is a fundamental ingredient to feeding the world through fertiliser manufacturing but also many chemical processes.
If we ask ourselves the question of why so much grey hydrogen is used and how can that be made sustainable the plot thickens somewhat. The real answer is that when natural gas prices are low, grey hydrogen is cheap, often below $2/kg. There are challenges though as during the invasion of Ukraine when international energy markets were disrupted, the price of grey hydrogen exceeded the price of green hydrogen, produced by splitting water with an electrolyser. This highlights one of the two challenges of grey hydrogen, it is susceptible to price volatility and produces a large amount of CO2.
For those looking from the outside in – and for some within the industry even – it might be natural to question the point in advocating its use and pushing the growth of hydrogen technologies, if the hydrogen we’re producing and using is not significantly cleaner than conventional fossil fuels. And this is why we have to look at green hydrogen as the final goal.
Electrolysis: a key piece of the clean energy puzzle
Green hydrogen is generated through electrolysis, where electricity derived from renewable sources like wind, solar or hydropower is used to split water molecules into hydrogen and oxygen. There are a host of economic and societal benefits to utilising this method of hydrogen production that extend beyond the obvious environmental benefits.
The push for energy sovereignty, for example, which has been escalated by net zero ambitions, but also by events such as the Russia-Ukraine conflict, is one of the main benefits. Countries worldwide are increasingly recognising the need to make their economies less vulnerable to volatile international politics and external factors for energy security.
Here in the UK, we’re well placed to rely on substantial renewable energy, so the development of renewables in sufficient quantities that can be stored to protect against seasonal variability would mean we are no longer reliant on imported fuel sources, creating a stable market for ourselves. Green hydrogen, produced by electrolysis is key to unlocking this solution.
With other benefits including stimulating economic growth, grid stability and helping industry comply with emissions regulations, it’s not surprising that several countries have already set targets for deploying electrolyser capacity in their national hydrogen strategies, though a target is one thing, getting there is something completely different.
Various electrolysers either on the market or in development are available and choosing which to leverage involves considering several factors. Should technologies with a track record of successful deployments and established supply chains be favoured by governments, or should they prioritise electrolysers that offer higher efficiency, faster response times, hydrogen purity and operational flexibility?
Let’s recap on the four main types of electrolysers:
- Alkaline Electrolyser: Using an alkaline solution (like soap), these are the most mature and widely used type of electrolysers having been an established technology for >50 years. They have a well-established supply chain and often have the lowest costs (due to the relatively low cost of materials used in their simple construction). However, they are usually massive units due to relatively low power density, are known for being less suitable when it comes to coupling with renewable power sources, and also have limitations related to operating pressure, hydrogen purity and production efficiency.
- Proton Exchange Membrane Electrolyser (PEM): Using an acid based chemistry (think lemon juice), PEM electrolysers can operate at higher current densities, making them more compact and responsive to fluctuations in power supply – ideal for coupling with intermittent renewable energy sources. Their modularity means they can be easily scaled up or down by adding or removing individual stack modules, and benefit from rapid response times. They do, however, tend to have higher upfront costs compared to other types of electrolysers – this is mainly because they use large quantities of expensive metals like platinum and iridium which limits the opportunities to substantially reduce costs.
- Anion exchange membrane Electrolyser (AEM): Often thought of as the best of both of the low temperature worlds, AEM utilises the chemistry of alkaline with the structure of a PEM electrolyser. They’re responsive to intermittent power sources, but don’t require an acidic environment. This allows for the use of non-precious metal catalysts, potentially significantly reduces costs and simplifies supply chains. Efficiency and response time are comparable to PEM, and they can produce high-purity hydrogen. However, compared to more established electrolyser technologies, AEMs are in the developmental and early commercial stages. This means that while they offer several advantages, they also need to essentially ‘prove themselves’ to gain widespread adoption and commercialisation.
- Solid Oxide Electrolyser (SOEC): An SOEC runs at a very high temperature, often above 600°C but also a high efficiency. As such it’s practical to use them in industrial scenarios where a plentiful supply of industrial waste heat is available and where the operating scenario is one of consistent long-term operation rather than anything more dynamic such as load following of renewable electricity generation technologies. Like AEM, SOEC is at an earlier stage of commercialisation when compared to Alkaline or PEM but a number of companies worldwide are pushing forward with this as an option particularly where they have successfully developed the fuel cell equivalent, a solid oxide fuel cell (SOFC) technology solution.
According to the IRENA’s 2022 patent insight report ‘Innovation trends in electrolysers for hydrogen production’, projections suggest that by 2030, global water electrolyser capacity will grow to around 213 GW. It’s a substantial increase from the current capacity of about 1.1 GW, but is critical for achieving economy-wide decarbonisation goals and still a drop in the ocean compared to the total estimated requirement to decarbonise and grow the hydrogen economy through Net Zero which would exceed 2000 GW.
To meet the rising demand for green hydrogen, there’s a pressing need to significantly increase the production and deployment of electrolysers – and for that, we need substantial technology innovation.
Supercharging electrolyser impact with technological innovation
The main way we can increase the production and deployment of electrolysis is to make it lower cost (especially compared to fossil-based hydrogen). But to do that, we need to make electrolysers lower cost too, which is why new technology is required.
According to IRENA, investment costs for electrolyser plants can be slashed by up to 40% in the short term and 80% in the long term through various strategies, including improved design, economies of scale, material substitution, enhanced efficiency, and operational flexibility. There’s also a need for advancements that increase both process efficiency and the lifespan of electrolyser technology.
Making the technology more competitive will trigger deployment, giving us important learnings and data, which enables lower cost, attracts private capital for R&D and drives further improvement.
Put simply, if we want to make sure that ultimately all hydrogen used is green, we have to use and invest in electrolysis more.
On the upside, IRENA’s patent data shows an increase in invention activity in technologies leading to reduced costs of electrolysers – thanks to innovators like Bramble Energy, for example. At Bramble Energy, we are currently working on integrating Printed Circuit Board (PCB) manufacturing techniques with AEM technology. The idea is that the modular nature of PCB designs could allow these integrated electrolysers to be easily scaled up or down depending on the required hydrogen production capacity, making it suitable for everything from small-scale mobile applications to larger, industrial-scale hydrogen production. It could also lead to a more compact, efficient, and less expensive electrolyser, while the precision of PCB manufacturing allows reliable manufacturing at scale.
Navigating challenges in electrolyser advancement
The integration of AEM and PCB technologies in electrolysers is just one example of how innovations in materials science and manufacturing techniques can potentially revolutionise energy technologies. But there are challenges ahead across all types of electrolysers. Take supply chain issues. PEMs constantly struggle with precious metals supply, seeing iridium prices quadruple during COVID, while even alkaline electrolysis relies on materials that may face constraints such as Nickel which has been volatile given its increasing use in battery supply.
There are significant issues with human resource constraints across the sector. If we are to navigate the complexities of electrolyser technology effectively, investment in talent, training, and skill development is crucial.
Given the limitations of off-the-shelf options, developing custom testing setups and standards tailored to electrolyser specifications is also key moving forwards. If we can ensure rigorous testing and validation of electrolyser performance, reliability, and safety, we can truly accelerate the development and deployment of efficient systems.
We need greater collaboration between academia, industry, and policymakers – we need academia to continue innovating, researching and developing; we need industry to take those innovations and put them into practice for blueprint and commercialisation purposes; and we need policymakers to support the other two with subsidisation policies for the use of green hydrogen, setting targets with investment funds, and keeping it at the forefront in climate action policy.
While these challenges may seem big, there is much optimism. When policymakers and researchers share a vision for an innovative, low-carbon hydrogen industry that can combat climate change, resources become available and innovation blossoms, this is what created Bramble Energy after all.
Source:Hydrogencentral