"Hydrogen CHP units are still a niche segment, but interest is growing rapidly"

2G has been developing combined heat and power plants for 30 years. Initially, the Münsterland-based manufacturer mainly supplied farmers and therefore specialized in biogas. Later, new applications and natural gas operation were added. In 2012, 2G built its first hydrogen-powered plant. In an interview, Jan van Ooijen explains what advantages the “H2 CHP” has over other options for decentralized power supply and how the company is preparing for the hydrogen ramp-up.

gwf: Mr. van Ooijen, how does a CHP function?

Jan van Ooijen: In a CHP plant, a combustion engine generates electricity and heat simultaneously: the engine drives a generator to produce electricity, while the waste heat from the engine is used via heat exchangers for heating or hot water production. With this principle of “combined heat and power,” overall efficiency levels of over 85% can be achieved.

gwf: What applications are CHP units suitable for?

Jan van Ooijen: The spectrum is very broad: in the building sector, we supply residential complexes and apartment buildings, hotels, hospitals, nursing homes, universities, schools, swimming pools, and even stadiums. In the industrial sector, we work with breweries and many other industries, for example.

gwf: What is the biggest advantage of a CHP?

Jan van Ooijen: That they supply electricity independently of the grid! There are currently massive problems with the availability of electrical energy throughout Europe. The grid is simply not large enough — and the trend toward heat pumps is exacerbating this. In many European countries, heat pumps have been gaining ground for years — which is a good thing in principle. However, this is causing increasing problems for the electricity infrastructure, as energy suppliers will not be able to supply enough electricity in the foreseeable future. There, they say, “Sorry, grid connection won't be available until 2030.” This slows down economic development as a whole. In my home country, the Netherlands, alone, around 10,000 projects are currently on hold due to these challenges. CHP plants can help here by supplying electricity everywhere  — whether with biogas, natural gas, or hydrogen.

gwf: 2G describes itself as the global market leader in hydrogen CHP units. How did this come about?

Jan van Ooijen: In 2007, we went public in Frankfurt to raise more capital for research and development. Since 2008, we have been developing hydrogen-based CHP systems. In 2012, we installed our first 100% hydrogen prototype at Berlin Airport. In 2018, we commercialized the concept. These CHP systems are now in operation at several locations worldwide. Most are pilot projects that demonstrate the versatility of our technology in different application areas and climate zones: there are plants in Japan, the Middle East, Europe, and the US.

gwf: What does a typical use case for H2 CHP look like?

Jan van Ooijen: We see the CHP unit as part of an overall system comprising PV systems, wind power, electrolysers and efficient H2 storage – ideally connected to the grid. This allows you to use some of the electricity immediately and convert the surplus into hydrogen. This can then be stored and converted back into electricity and heat via the CHP unit as required. This is particularly interesting because the sun and wind are not always available. And this happens everywhere — even in Saudi Arabia, there are periods when no renewables are available.

gwf: What distinguishes your hydrogen solution technically from conventional CHP units?

Jan van Ooijen: The decisive difference lies in the mixing process. For natural gas applications, we use an external mixer: air and gas are mixed homogeneously outside the combustion chamber, and then the finished mixture enters the cylinder via the intake valves. For hydrogen, on the other hand, we use a port injection process: it is separated from the air and only injected into the combustion chamber shortly before ignition.

gwf: Why is this distinction so important?

Jan van Ooijen: Hydrogen has completely different combustion properties to natural gas: the molecule is extremely small and highly reactive. If H2 and oxygen are mixed outside the combustion chamber, there is a risk of spontaneous combustion or even backfires in the intake system. Port injection technology ensures that the mixture burns in a controlled manner by introducing it in a targeted manner via a spark plug.

gwf: You advertise that you can mix hydrogen and natural gas in any concentration.

Jan van Ooijen: That's right. This is particularly relevant during the transition period: if you currently use a gas engine in your CHP, we can convert it to run on up to 40% hydrogen without having to modify the engine configuration. Users who have access to hydrogen can significantly improve their carbon footprint through this blending. Conversion is always possible.

gwf: That means you are H2-ready?

Jan van Ooijen: I would say: we are not only H2-ready, we are H2-proven. We have now successfully completed almost 40 projects on three continents. These pilot projects prove that we know how to handle the gas. At the same time, we are of course also H2-ready, because if a customer needs a natural gas CHP plant today but knows that hydrogen projects are being developed in their region, we can adapt the system for 100% hydrogen later on.

gwf: What output range do you cover?

Jan van Ooijen: With 100% hydrogen applications, we achieve up to 750 kW of electrical power. With natural gas, we achieve 1 MW. The performance is therefore slightly lower so as not to overload the system. However, we are already testing hydrogen use in larger engines at our R&D facilities.

gwf: Does the use of hydrogen also bring its own challenges?

Jan van Ooijen: Yes, availability and transportability. Hydrogen has about one-third of the energy density of natural gas. So you need three times as much volume for the same amount of energy. If you want to transport it through pipelines, you have to pump three times as much hydrogen through them, which requires higher pressure. When it comes to availability, it must be said that green hydrogen is still relatively rare and expensive today. But it is expensive precisely because it is rare — as availability increases, the price will fall. It's like gold: if everyone could find it in their backyard, it wouldn't be valuable.

gwf: How do the efficiencies of natural gas and hydrogen compare?

Jan van Ooijen: The electrical efficiency with natural gas is around 43% at an output of up to 750 kW — with hydrogen, it is only slightly lower — and, above all, it is still higher than most natural gas engines on the market.

gwf: While we're on the subject of comparisons: other manufacturers rely on stationary fuel cells for decentralized power generation using hydrogen. Why do you prefer CHP units with combustion engines?

Jan van Ooijen: There are several reasons for this. First, we are about five times cheaper than fuel cell systems. Second, fuel cells require extremely pure hydrogen — we can also work with low purity levels and even add natural gas. Third, fuel cells are very fragile, while our systems are characterized by greater robustness and resistance to shocks, weather conditions, and so on. And fourth, we have simpler start-stop cycles and can therefore respond more flexibly to load fluctuations.

gwf: Is there a certain degree of technological competition here?

Jan van Ooijen: You could see it that way. It seems to me that when it comes to off-grid H2 solutions, everyone immediately thinks of fuel cells. But that's because not everyone is aware of the advantages of CHP. Here's an example: In 2018, a project was launched in the Netherlands to operate a hospital with zero emissions. It uses a fuel cell in combination with solar panels, electrolysis, and hydrogen storage. I recently met the project manager and showed him our CHP concept. He said that if he had known about it at the time, they would have chosen it. Our system would have been more robust, cheaper, and easier to use.

gwf: For around two years now, you have not only been a CHP manufacturer, but also offer heat pumps. Can these also be operated with hydrogen?

Jan van Ooijen: There is indeed an interesting combination for this, which we call “GreenCube”— a heat pump setup combined with a CHP setup. The idea is again to solve the problem of an overloaded grid. Imagine: a building needs a heat source but does not yet have access to grid power. We then install a CHP unit next to it, which supplies power for the heat pump until the grid connection is available. Later, the heat pump runs normally and the CHP unit becomes a backup.

gwf: Are further innovations planned?

Jan van Ooijen: Yes, we are currently developing CHP units for demand response solutions — both with natural gas and hydrogen. These are emergency power generators that are intended to replace diesel generators. You still see diesel generators in hospitals and many other applications as backup systems. This is very harmful to the environment and CO2-intensive.

gwf: So, the technical possibilities for using hydrogen do exist. How do you see the H2 economy as a whole?

Jan van Ooijen: We are currently moving from the pilot phase to the industrial phase. Demand is increasing, and the number of exhibitors and visitors at trade fairs has multiplied in the last two years. More and more companies are getting involved in this area. But we have to remain realistic: of the 2G's over 9,000 CHP units installed, only relatively few are currently running on hydrogen. So it is still a niche segment, but interest is growing rapidly. I believe that over the next ten years we will see a mixture of both large-scale applications, where hydrogen is transported via the grid and replaces natural gas, and local applications, where hydrogen is produced locally. Once you're there, you can build a truly beautiful ecosystem.

gwf: Mr. van Ooijen, thank you very much for the interview.