Sector coupling with green hydrogen

In early October 2020, Siemens Mobility and Siemens Energy announced that they are collaborating on the development of hydrogen solutions that will make it possible to produce and use sustainably generated hydrogen across sectors. Together, the companies want to offer their customers complete solutions from a single source that include everything from production and infrastructure to the fuel cell-powered Mireo Plus H. But what makes hydrogen such an attractive fuel? Natalia Westhaeuser, Vice President of New Energy Business at Siemens Energy, spoke to us about this and about exactly what solutions Siemens Energy is offering in this context.

Ms. Westhaeuser, what’s your take on the current market for green hydrogen?

In Germany, the market for green hydrogen is still in its infancy, it’s still dominated by “gray hydrogen”. But over the next few years, it’s going to undergo serious development. The total global demand for hydrogen is currently at around 70 to 80 megatons a year. We’re assuming that by 2050, this will have risen by 600 percent, with a stronger trend toward green hydrogen. The main reason behind the increase in demand is the fact that only about 50 percent of the world’s power consumption can be electrified.


What exactly is “gray hydrogen”?

“Gray” or “brown” hydrogen is based on a fossil fuel. This still applies to 95 percent of global hydrogen generation. For example, hydrogen is obtained via steam reforming of methane or coal gasification, both of which produce CO2 emissions. If we’re to avoid emissions and meet our climate goals, the future demand for hydrogen will have to be increasingly met by emission-free, “green” hydrogen generation technologies. In the future, we want to focus on green hydrogen in our complete solution with Siemens Mobility.

Green hydrogen is the oil of the future.
Natalia Westhaeuser, Vice President New Energy Business, Siemens Energy

What conditions does hydrogen have to meet to be “green”?

Hydrogen is “green” only if it’s produced by water electrolysis using renewable, CO2-free sources such as wind or solar energy. Electrical current is used to split the water into hydrogen and oxygen. Taking it even further, only sustainably generated energy should be used to desalinate the water for electrolysis if no desalinated water is available.


How long has Siemens been researching green hydrogen?

We’ve been working on hydrogen electrolysis for over a decade. The first industrial prototypes of our SILYZER 100 electrolysis systems, which have been deployed in various demonstration projects since 2011, were able to produce only a few kilograms of hydrogen per hour. An important milestone was the 2015 market launch of our SILYZER 200 systems on a megawatt scale, which were already able to produce 20 kg of hydrogen per hour and were deployed in several of the world’s largest power-to-gas projects. Our latest product is SILYZER 300. With a power demand of 17.5 megawatts and a production capacity of 335 kg of hydrogen per hour, it’s one of the largest electrolysis systems available on the market. Within the last decade, we’ve been able to take our electrolysis systems from the prototype stage to series production while maximizing system efficiency and cost-effectiveness through the appropriate scaling.

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Annual demand for hydrogen today

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Growth in consumption by 2050

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Hourly capacity of SILYZER 300 at 17.5 MW

In the mobility sector in particular, a lot of transportation is being electrified and equipped with batteries. Why do we need hydrogen?

Far from being incompatible, battery technology and hydrogen technology optimally complement one another. Batteries are excellent for smaller modes of transportation, shorter ranges, and lighter loads. Hydrogen is ideal for longer ranges or for transporting heavy loads, which is generally what’s required for air, marine, heavy cargo, and railway transport. In this case, the benefits of hydrogen are a high storage capacity and fast fueling.

What solutions is Siemens Energy offering in the area of hydrogen?

The core of a green hydrogen infrastructure – and also our central product – is the electrolyzer. Siemens Energy’s focus is explicitly on the Proton Exchange Membrane (PEM) process. But we’re also offering our customers a complete solution that includes everything from grid connection to transformers and converters, as well as suitable software and solutions for cleaning and compressing hydrogen – all from a single source. In the future, we’ll be working with Siemens Mobility to offer complete solutions that range from the production of hydrogen to its use in the Mireo Plus H fuel cell train.

What are the major benefits of hydrogen as a fuel?

The greatest benefit is the fact that hydrogen can be stored for long periods of time and is easier to transport via pipeline systems. Whereas batteries store only a limited amount of electricity based on their size, it’s possible to generate and store tremendous quantities of hydrogen. We need scalable transport and storage technology in order to stabilize fluctuations in power generation caused by renewable energy, make our energy systems more flexible, and decarbonize the different sectors. In Europe, we already have this type of energy storage and transport system for natural gas. It permits the storage of huge quantities of natural gas using pipeline systems as well as pore and cavern storage. We’re currently working on designing this type of system based on hydrogen as a zero-emissions fuel. The first projects involving hydrogen pipeline systems and underground cavern storage are already underway in Germany. These projects are the first step toward a pan-European hydrogen network that will serve as the basis for decarbonizing our energy systems and will make hydrogen a key element in the energy transition.

What is sector coupling and what role does hydrogen play?

Until now, the focus has been on decarbonizing the electricity sector – referred to as “coal phase-out”. However, the emissions from this sector account for only about 40 percent. Transportation and industry are each responsible for around a quarter of our energy demand. These sectors also need to be decarbonized, which often can’t be done using direct electrification or battery technology. As a fuel, green hydrogen also makes it possible to use renewable energy in other sectors and in this way decarbonize large sections of our energy system.

What are the benefits for customers when they procure their trains and hydrogen infrastructure as a complete solution from a single source?

Hydrogen energy systems have to be thought of as complete value chains. Today, diesel trains are still being used on many lines. To meet the requirements of a customer converting to hydrogen trains, the hydrogen infrastructure and fueling solution have to be adapted to the customer’s fleet and railway network. But we also want our optimized, complete solutions to set standards in order to reduce costs and guarantee availability. Siemens Energy and Siemens Mobility cover the entire value chain for green hydrogen, including renewable energy sources, grid connection, production, storage, transport, and fueling – all the way to its use in the Mireo Plus H fuel cell train. Compared to our competitors, we’re more broadly positioned and can guarantee easy scaling and a fast market ramp-up.

What’s your vision for hydrogen as a fuel source for Europe and the world?

Green hydrogen is the oil of the future. The oil age won’t end because we’ve run out of oil, any more than the stone age ended because humanity ran out of stone. Innovation and scaling will make both green energy and its molecular production (green hydrogen) more affordable so that the use of fossil fuels will no longer be justified. Currently, however, the green hydrogen industry needs a regulatory stimulus, like what was given to wind energy 20 years ago.