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Water electrolysis…the zero-carbon H2 solution


O. JENSEN, Nel Hydrogen, Zealand, Denmark

H2Tech (H2T) sat down with Ole Jensen (OJ), Business Development Director of Northern Europe for Nel Hydrogen, to discuss the global hydrogen (H2) economy.

H2T: As a global electrolyzer supplier, what is your unique perspective on the status, acceptance and investments in various H2 economies?

OJ: To best understand where we are, it is helpful to look back almost a century ago to 1928. That was when the first alkaline electrolyzer production site was established, and it was 300 megawatts (MW). While the process is almost 100 yr old, it has many applications for today’s needs; however, the public has just become aware of its uses in producing H2 as a fuel for vehicles, generating heat and electricity, as a chemical feedstock for ammonia and steel, and as a commodity for trading with other countries. Today, H2 is where wind generation was 20 yr ago, but the growth in interest and real investment for H2 is on a very speedy trajectory. About 5 yr–7 yr ago, no one talked about green H2 as a potential replacement for fossil fuels. By 2019, many countries already had written strategic plans for the H2 industry and economy. The U.S. leads in establishing a H2 supply chain infrastructure; however, Europe, Australia and Asia are close behind. There is tremendous momentum for H2 as a viable and clean energy source, and new projects for H2’s many applications are announced almost weekly around the globe. 

H2T: With such robust demand the horizon, how will electrolyzers keep up?

OJ: You make a valid point. Electrolyzers are the cornerstone of carbon dioxide (CO2) reduction worldwide. It took roughly 20 yr for wind turbines to be where they are today. Electrolyzers will take but a fraction of that time because of the massive investment in research and development (R&D) and a greater sense of urgency. In Nel’s case, we are gathering a tremendous amount of data from new and existing sites, so we know exactly how the equipment responds and how much power is being consumed. This information is crucial to help us improve efficiencies, reduce power consumption, lower costs, and make electrolyzers with the lowest possible CO2 footprint. That is a goal of ours, as well. When windmills just came onto the market, it took nearly 10 yr before a wind turbine was CO2 neutral because it took so much energy to produce wind turbines and the blades. It will not take electrolyzers that long. It is already in our R&D planning to ensure that we are addressing all factors simultaneously. We are monitoring several parameters to advance the electrolyzers we will supply to the market, not just immediately but also 5 yr–10 yr from now (FIG. 1).

Hydrogen technology on the maturity curve.

H2T: Can you expand on what you are doing regarding CO2 reduction in your electrolyzer manufacturing processes?

OJ: Nel is taking a unique position, and it is the right approach. Without giving too much away with our proprietary advantages, one of the areas we are testing is the materials we are using to ensure they have the lowest CO2 footprint in the market.  

H2T: The topic of green H2 is complex, as we all know, with many stakeholders and an abundance of patience required for reality to catch up with the vision. What movements, trends and practices are you encountering?

OJ: One of the big challenges in the green H2 initiative are the natural fluctuations in the renewable power source to generate electricity, specifically wind, solar and hydro systems. The output varies from day to night and seasonally. Many weather factors and earth cycles affect energy source profiles. The offtaker profiles are another aspect with many variables. How will the green H2 be used? Is it for trailer tank transport? Is it for the petrochemical industry? Is it for fueling or the food industry?  

In most cases, electrolyzers will be connected to the large main power grid and, in some cases, a microgrid. Microgrids are smaller grids unconnected to centralized grids, such a remote 500-MW wind or 200-MW solar farm or smaller urban grid. By their very nature, these microgrids are less consistent than the big, centralized facilities, and there is less room for storage. However, microgrids will grow in number.  

One significant trend we see is that more companies and utilities are moving away from a centralized H2 generation approach. Companies want to be able to produce green H2 in remote locations but close to the consumers, meaning close to a city, in an urban residential area, near a harbor or next to a trucking fuel hub. Therefore, space is minimal, so we must consider the number of electrolyzers required (the footprint of the generation site). We are devising successful scenarios in which much fewer electrolyzers are required to produce the same capacity as the more centralized facilities. 

Conversely, a growing number of H2 production sites are still getting larger. Three years ago, a 10-MW electrolyzer project was massive, but today we are examining 200-MW, 500-MW and even 1-GW projects in certain feasibility studies. This will significantly impact how the grid will react when they come online.  

H2T: What are the H2 generation solutions being considered to accommodate the fluctuations in renewable power?

OJ: The most important factor for a green H2 investor is discovering the optimal efficiency point at all times of day, night, winter or summer. Consequently, it is essential to analyze the renewable source, offtaker profile and power grid. Why do I say power grid? Sometimes there can be restrictions. The more renewable power you get into a grid, the more frequency fluctuations. For example, where I am in Denmark, the wind blows a lot. We have 85% of renewable energy in our grids. The grid owners ask the consumers and offtakers if they can take more load. This is where grid services will play an important role. Grid services are various services that keep the frequency and voltage of the power grid stable. Grid services will become increasingly important the more renewable electricity flows into the main grids. In the U.S., Texas and Oklahoma are windy states and will focus more on grid services in the future. 

The electrolyzer production facility can also be a grid service provider to stabilize the grids. In Denmark, the energy is nearly free of charge because it is so windy, but it is part of the grid services, and consumers have been asked to put a little bit more load or offload onto the grid, so our frequency is kept stable.  

H2T: What role do electrolyzers play in stabilizing the green H2 power grids? Does one technology have an advantage over the other?

OJ: We have studied how we can take different electrolyzer technologiesproton exchange membrane (PEM) and alkaline electrolyzersand achieve the best balance in the grid and optimal efficiency point for the operator or production facility owner. The result is combining PEM and alkaline systems into the system for the best stabilization. The foundation for H2 production in a grid is alkaline because it is efficient and robust. Where there is fluctuation in power generation or consumption, PEM electrolysis takes over due to its ability to adjust instantaneously to these power fluctuations and help balance the grid.  

H2T: Is a mix of the electrolyzer technologies the answer across the board?

OJ: Only in certain segments, but those are the growing ones. Again, the source and offtaker profiles must be considered. In those situations, where fluctuations were happening and tolerated, mixing the two methods of electrolysis can balance the best efficiency point for the operator and provide grid services to the grid owner to minimize disturbances and fluctuations. This is important because we will get more renewable energy in the grid. For example, in some countries, we can have nearly 100% of power consumption covered by renewable energy. However, in other countries, there may be only 15%–20% renewable sources in the grid. We must remember that renewable sources will evolve to dominate grid power for all European and westernized countries. Although it is not imperative to think about stabilizing and balancing, it makes sense to get ready and perhaps combine the two electrolyzer methods (FIG. 2).

Alkaline and PEM electrolyzers.

H2T: In what cases are renewables and mixing electrolyzer technologies not recommended?

OJ: Some ammonia refineries and petrochemical facilities cannot handle fluctuations. This will likely change as more research and experimentation are conducted. For example, we are learning and reading more about green ammonia. 

H2T: Any closing thoughts? 

OJ: Our message at Nel is to begin a H2 infrastructure in the supply chains where it makes sense. It does not need to be massive or perfect, but it can and should be on a small-to-modest scale. This is how we all learn best practices: what works, what does not, and what we need to do next. This is the data that I referred to that we and all parties are gathering. It is imperative to have even small sites working from which all the stakeholders can learn and adapt. With all the talk, plans and hype surrounding H2, we need more real working sites. In some countries, redundant laws and regulations are slowing down progress. Let’s all work to cut the roadblocks and start enjoying the promise of H2.H2T


OLE JENSEN is a specialist in the energy industry with a passion for sustainability and renewable energy. His flair for methods of decarbonizing products and services is pushing progress toward a cleaner and more flexible energy system, in which H2 is a cornerstone of success. At Nel Hydrogen, Jensen advises customers, leveraging his trilingual communication skills to nurture multi-national partnerships that further business goals. He brings a deep understanding of regulatory and statutory compliance to the business, alongside a strong focus on safety and a proven ability to reduce costs and increase revenue. He thrives in agile environments, nurtures a culture of excellence and analyzes industry and consumer trends to create future-proofed products and services.