Interview with Thomas Korn, CEO of water stuff & sun
Startup company water stuff & sun has developed a novel technology that is designed to provide a safe and easy way to store hydrogen. The solution’s key component is its microvalve system. A pressure regulator controls the release of hydrogen progressively from 1,000 bar down to just a few bar. H2-international spoke to Thomas Korn, CEO of water stuff & sun, about how it works and the challenges encountered.
H2-international: Mr. Korn, the storage and refueling of hydrogen is a challenging issue. How do you solve that problem?
Korn: As it stands, the storage of hydrogen in conventional compressed gas tanks is complex and expensive. There is a trade-off between performance, safety and cost. We have a surprising solution to this: Instead of using a small number of large cylindrical tanks, our technology allows us to store the same amount of hydrogen in multiple spherical carbon-fiber vessels the size of a tennis ball. The silicon microvalve system, which is built into every pressurized ball, means that all the vessels act identically and in unison, just like a large tank. The expense involved in ensuring the safety of hydrogen stores can be significantly reduced if the energy is split into multiple small vessels. As a result, we save almost half the carbon fiber material compared with a standard pressurized tank. We call these ball-shaped high-pressure storage vessels Sfeers.
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They allow hydrogen cells to be scaled as required and integrated into hydrogen batteries of any shape. Green hydrogen can thus be used in a variety of motive and stationary applications such as trucks, drones and airplanes. The next generation of these energy stores will be 95 percent lighter and up to 30 times cheaper than lithium ion batteries – while still carrying the same amount of energy.
Fig. 2: Doing the rounds: a Sfeer ball at the EES trade fair in Munich
How does the hydrogen battery work?
Hydrogen batteries are low-pressure hydrogen tanks containing Sfeers which are filled at up to 1,000 bar. The hydrogen battery enclosures are designed for low pressures and can therefore be perfectly adapted to the available installation spaces in a wide array of mobility products. When hydrogen is extracted, the pressure in the hydrogen battery enclosure decreases and activates the microvalve system in all the Sfeers once the pressure drops below a mechanically programmed ambient pressure range. These then release hydrogen, together providing the energy required for a hydrogen engine or a fuel cell.
The pressure in the hydrogen battery rises again above the pressure activation level that is set during the manufacture of the micromechanical components. Once the pressure level has been reached, all the microvalves close. The pressure in the battery stays constant or reduces further if the consumer withdraws more hydrogen. The activation pressure is set to the supply pressure of the consumers. The hydrogen battery can be thought of as a low-pressure tank, but with the capacity of a high-pressure tank.
The concept increases the safety level while at the same time reducing the amount of material used. Since their highly adaptable shape means they can make best possible use of the available space, hydrogen batteries outperform conventional pressurized tanks in terms of volumetric and gravimetric power density.
Microvalve technology has its origins in satellite technology. How is this technology produced?
Satellites have a gas propulsion system that secures their position within the communication window. Even in the early days, industrial developers started to use microsystem technology to regulate gases due to financial pressure to make ever smaller and lighter satellites. Our innovation centers on the development of micromechanical switching elements that don’t need electrical energy for their control; instead they are controlled passively by the ambient pressure. As in semiconductor engineering, highly industrialized manufacturing processes are used that can create thousands of identical parts on large silicon wafers. Valves, gas channels and the five-stage pressure regulator are produced and joined in four silicon layers. All chip components are built into a space measuring 4 x 4 x 2.5 millimeters (0.16 x 0.16 x 0.1 inches).
How did you come up with the idea of spherical high-pressure vessels?
The technology was invented by Prof. Lars Stenmark, who taught microsystem engineering in the Ångström Laboratory at Uppsala University and who had already applied earlier inventions to the aerospace industry. When he told me about his hydrogen storage invention, I was all for it. A physical hydrogen storage vessel that combines two existing technologies and resolves the trade-off between safety, cost and performance in hydrogen tanks – we couldn’t resist and founded the company water stuff & sun in January 2017.
Fig. 3: A view of the lab shows the test setup for microchip evaluation
Is there already a prototype?
We have already produced and tested prototypes of switching valves and the key element of the valve system – the pressure regulator – in the clean room of the Ångström lab in Uppsala. We have also put a carbon fiber Sfeer prototype through a burst test and validated our simulation model with the results. At the moment we are building the first system prototype of a hydrogen battery with three Sfeer cells. The prototype and its use in a micromobility application will reach technology readiness level 5 in the first half of 2024. At that point we’ll start to develop hydrogen batteries for specific mobility products with several manufacturers and go on to industrialize them in the next stage. There is a great deal of interest from industry. For example, we have already submitted a joint funding project with an aircraft manufacturer and the German Aerospace Center. We are working with our partner Keyou to develop hydrogen batteries for converting and retrofitting trucks and buses. Additionally, we’ve managed to stimulate interest from a mining machinery manufacturer and a truck OEM.
Returning to the refueling process: Am I right that you are intending to swap the tanks?
Hydrogen batteries don’t need to be refueled in the vehicle; they are exchanged at swap stations or, in the case of small applications, they can also be exchanged by hand. That way, refueling can take place quickly and cost-effectively. The empty hydrogen batteries are refilled at central compressor stations and returned to the swap stations. The low operating pressure and the limited quantity of H2 in the hydrogen battery enclosure makes this ease of handling possible. In comparison with conventional high-pressure or liquid hydrogen refueling stations, the expense and complexity are significantly reduced, which in turn lowers the capital and operating costs and thereby also the hydrogen price. For heavy-duty vehicles, for instance, with hydrogen, several hundred liters of fuel energy equivalent need to be compressed, cooled and transferred. By simply swapping the hydrogen battery, the process can be completed in just a few minutes.
The financing required will be considerable. What are the next steps for your company?
The need for capital in a tech startup is always an issue – it’s a continuous process. We have just started a new financing round in which our existing investment partners, such as the investment arm of Kreissparkasse Esslingen-Nürtingen, or ES Kapital for short, the company Besto, run by the entrepreneurial Beyer and Stoll families, and machinery and tooling factory Nagel, have already registered an interest. I would refer to them as relatively down-to-earth, regional investors that have been involved from an early stage. The plan is to invest the new cash in the development of a prototype in the motive application area, as mentioned earlier, among other things. The raw materials for the production of semiconductor chips are all affordable. Carbon fiber and silicon are readily available on the market. That is an advantage in terms of further scaling. If everything goes according to plan, we will see the first of our batteries in a vehicle or aircraft by 2025.
Fig. 4: The H2 battery should be quick and easy to swap in and out of a truck
When and how will the market for your solution evolve?
The transformation of energy systems is well under way. Infrastructure for natural gas- and oil-based fuels is being replaced by hydrogen and liquid hydrogen derivatives such as ammonia, methanol or synthetic fuels. The competition for technology leadership and, ultimately, energy leadership began long ago. In China and the USA, many billions of euros are now being invested in hydrogen technologies and their infrastructure; we Europeans are attempting to counter this with the Green Deal. Hydrogen projects are sprouting up all over the place. As far as we are concerned, the market has already started; we’re currently concluding cooperation agreements with initial vehicle and machinery manufacturers.
Where will the first market be that manages to develop?
We need to take a multitrack approach and are therefore also looking at the USA and the Arab world. The country that achieves the lowest hydrogen prices by investing will attract a lot of companies and investment. In the EU and Germany I hope that the greenhouse gas quota gives us an instrument that is competitive.
You won a prize at the World CleanTech StartUPs Awards, otherwise known as WCSA 2023. What particularly impressed the judges?
Firstly, the award as a platform is a very interesting network in itself. Applications for WCSA 2023 were invited by ACWA Power in strategic partnership with Dii Desert Energy and the French institute for solar energy CEA-INES, among others. The judging panel recognized the transformative potential of the hydrogen battery. The innovation could create an efficient and flexible infrastructure for H2. The electricity costs for hydrogen production from renewables are very low in Dubai. That’s why ACWA invited us again at the end of 2023 to present our solution locally. That will be extremely exciting.
In November we received two awards at the Global EnergyTech Awards: the prize for the Best CleanTech Solution for Energy and a special prize for Best Stand Out Performer. We were the only winners from Germany. That helps.
Interviewer: Niels Hendrik Petersen
Fig. 5: Thomas Korn
Thomas Korn has been working in the hydrogen field since 1998. The engineer’s experience includes work at BMW on fuel cell development. In 2015, he co-founded the hydrogen startup Keyou in Munich. The startup water stuff & sun was launched in 2017 in Unterschleißheim, Bavaria. The fledgling company now has 15 members of staff and a branch in Uppsala, Sweden.
The energy providers Thüga und Energie Südbayern (ESB) as well as Energienetze Bayern have converted parts of their gas network to 100 percent hydrogen in a test area. Mid-September 2023, the H2 feed-in system of the research project H2Direkt was put into operation in Hohenwart, regional district of Pfaffenhofen. Already in this heating period will ten customers be provided with pure hydrogen from there for 18 months initially via the rededicated gas network.
“The conversion of a natural gas network to 100 percent hydrogen with minor technical modifications is feasible, and the operation is safe,” said Bayern’s economy minister Hubert Aiwanger at the starting up ceremony. H2Direkt is therefore a blueprint for a climate-friendly energy supply.
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The feed-in system reduces the pressure of the supplied hydrogen and feeds it with 250 millibars into the corresponding network section. The green hydrogen required for this is being supplied by Westfalen AG in trailers by truck to Hohenwart.
The research institute DVGW-EBI had prior to this given the green light for all components installed in the distribution grid area. H2-suitable are also all the components installed in the boiler rooms of the households, including the original existing volumetric gas meters, which are perfectly suitable for accurate measurement with hydrogen. Due to the larger volume flow of hydrogen, they will nevertheless be replaced by commercially available but larger meters.
The 100-percent H2-capable condensing boilers come from the cooperation partner Vaillant. As part of the research project, regulations for the measurement of hydrogen are also being drawn up. The measuring concept for the field test has been approved by the calibration office (Eichamt) or the state office for weights and measures (Bayerisches Landesamt für Maß und Gewicht, LMG). H2Direkt is part of the TransHyDE project “Sichere Infrastruktur” (secure infrastructure) and funded by the German ministry for education and research (see p. 15).
At Fraunhofer FEP (Fraunhofer-Institut für Organische Elektronik, Elektronenstrahl- und Plasmatechnik), a pilot plant for the coating of metal sheets and strips is being used for the efficient coating of bipolar plates for electrolyzers and fuel cells. The institute, according to its own statements, is a leader in the development of electron beam and plasma technologies. This expertise could also advance hydrogen technology in the future.
One example of this would be plasma-activated electron beam evaporation. This is a vacuum coating process that enables both high throughput and high coating quality. Exactly this combination is crucial for the coating of bipolar plates for electrolyzers and fuel cells. Because these have to function for a long time, stably, in a chemically aggressive environment. For this, they must receive coatings that reliably protect the plates and at the same time guarantee electrical conductivity.
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Using electron beam evaporation, coatings to form a certain shape can be applied to the metal strip before these are stamped into bipolar plates, stated Burkhard Zimmermann, division manager for electron beam technologies at Fraunhofer FEP. The coating of the material is a crucial step for scaling the production with a roll-to-roll process. The challenge here is the formability of the coating. To ensure this, a dense macrostructure of the coating with the largest possible crystallites is required. Exactly these layer properties can be realized by the developed processes.
The company HPS Home Power Solutions has unveiled a new generation of its seasonal energy storage system. The Picea 2 now uses lithium batteries, which makes installation in the home easier due to the lower weight. With twice the power, the appliance is also equipped for e-mobility and heat pumps.
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The new research and development site is located almost directly next to the youth center of FC Union Berlin in an industrial area in Berlin-Niederschöneweide. In the future, not only kickers but also installers and partners will be trained there. But not only that; the new version of the seasonal storage unit is also to be manufactured there. “On-site installation is even more cost-effective for us, as the transport costs come out lower,” stated company founder and CEO Zeyad Abul-Ella – left in December 2023 and since then only still a shareholder – at the first presentation of the new device to an exclusive circle of visitors.
Nine years after its founding and a good five years after the first presentation of a Picea model at the trade fair Energy Storage in Düsseldorf 2018, there is a whole series of further developments of the product. The device has needed to change with the times. With Picea 2, the output power has therefore doubled to 15 kilowatts, which makes it possible to cover higher energy requirements, for example for an e-car or a heat pump. In the event of a power failure, the backup power supply ensures that important installations in the household are supplied with a stable power supply. “For each of the three phases of the three-phase current, the device now delivers five kilowatts of power,” explained Abul-Ella.
The new generation of the storage system also offers an increased connected load for photovoltaic systems – picking up on the trend in the market. Through new power electronics, according to HPS, efficiency was able to be increased, which means that higher levels of self-sufficiency are now possible. The energy utilization efficiency (Nutzungsgrad) including heat utilization is 90 percent. The electrical efficiency is between 35 and 40 percent.
Cooperation with competent partners
The device now uses an external inverter from SofarSolar, in which the software for the storage system has accordingly been adapted. “We do what we are really good at. For all other components, we rely on cooperation with partners,” said trained civil engineer Abul-Ella. The latter applies to both the inverter and the lithium batteries.
The AEM electrolyzer comes from the German-Italian company Enapter. The abbreviation AEM stands for anion exchange membrane. The technology uses more cost-effective materials such as steel instead of titanium and combines the advantages of alkaline electrolysis with the flexibility and compactness of PEM electrolysis. Enapter co-founder Vaitea Cowan was also present at the product launch, and Hans-Peter Villis, former EnBW (Energie Baden-Württemberg AG) director as well as partner from the very beginning and today chairman of the supervisory board at HPS.
Specifications for developers
“A tough requirement for the technical developers was to retain the dimensions for the slide-in boxes for the electrolyzer and the fuel cell in the energy center of the original Picea,” stressed Abul-Ella. The first Picea customers are pioneers. They should therefore also benefit from the innovations and be able to switch to them easily at a later date. A further development in the electrolysis module cools the hydrogen to 5 °C. This makes it possible to take in four to five times the amount of gas, because the moisture is now removed before storage.
New are also status displays that, at the touch of a button on the device or via the app, provide information about important system and storage statuses. The system always consists of an energy center and a hydrogen storage tank with a compressor that is installed outside the house on a concrete foundation. This foundation is absolutely essential.
The energy center unit has slimmed down considerably and now weighs 70 percent less: instead of 2.2 metric tons, now only 700 kilograms (1540 lbs). Reason is the switch from lead-acid to lithium batteries from the company Pylontech. The overall height has also reduced by 15 centimeters compared to its predecessor to 1.85 meters (6.07 ft). Doesn’t sound like much, but can be decisive for installation in a basement.
The Picea 2 costs at minimum 99,900 euros
The Picea module converts the surplus solar power in summer into hydrogen. In this way, large amounts of energy can be stored efficiently and over long periods of time. In winter, the gas, via a fuel cell, can be converted back into electricity and heat. The long-term storage capacity is up to 1,500 kilowatt-hours of electricity. In the smallest version with 16 gas cylinders, it is 300 kilowatt-hours.
The smallest version of the Picea 2 costs 99,900 euros. The gross price is the same as the net price, as the sales tax for the device, including storage units, is zero percent. With more storage capacity, the cost rises to up to 140,000 euros. This applies to a new construction where the installation can also be planned. In existing buildings, it can be a bit more complicated, so the amount may increase to up to 160,000 euros.
The demand seems to be there. Because over 500 devices of the first generation have been sold to date. More than 100 are installed at customers’ spaces.
Swedish port on the island Tjörn wants to be completely green
Plastic waste is a huge problem to the environment. One that is growing and growing with each passing day. On another hand, the global energy transition requires clean hydrogen in large quantities. So why not use the waste to generate the gas in a CO2-neutral way? Innovative technologies and projects show how this could be done. They are doing pioneering work and solving several problems all at once.
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The municipality Tjörn, north of Göteborg on the west coast of Sweden, has decided: It wants local energy production free of fossil fuels. The technology of Boson Energy from Luxembourg is to help in this. It takes non-recyclable waste and transforms it into clean electricity and green methanol. Green methanol could help the chemical and plastic industry replace fossil fuels.
The bonus: Both the electricity and the fuel for the port are to be negative-carbon through this, because Boson Energy’s process enables both a capture as well as the storage of CO2. With this process, the only solid that remains is a kind of slag. This can, however, be used as an environmentally friendly filling material or further processed into climate-friendly insulation material.
The first phase of the project required an investment of 100 million euros – the total cost will amount to around 450 million euros. “The project in Wallhamn will enable us to demonstrate all aspects of our circular economy vision,” said Jan Grimbrandt, founder and CEO of Boson Energy. The Swede is a green pioneer. He was already co-founder of the company Mobotec Europe, which has upgraded coal-fired power plants for operation with 100 percent biomass. In 2008, Grimbrandt founded the company Boson Energy.
Use in the port and in greenhouses
The project on the island Tjörn is now to demonstrate how a changeover can be made for areas and applications in which decarbonization is likewise difficult: fuels for ships, the chemical industry, fertilizers and in greenhouses for local food production. “This project will be a model for the world,” Grimbrandt is certain. And not just for ports, but also for cities and islands confronted with energy access issues and want to get away from fossil fuels.
Fig. 2: Signing the memorandum of understanding – Torbjörn Wedebrand (CEO of Wallhamn AB) on the left and Jan Grimbrandt (CEO of Boson Energy SA)
Boson Energy has already signed an agreement with the startup Ecopromt. From the cooperation, a greenhouse for vegetable growing is to appear near the port. The concept developed by Ecopromt shall ensure a circular and space-efficient vegetable production in this – that doesn’t impact the environment. Putting the growing facility in the vicinity of the Boson Energy plant enables electricity, carbon dioxide and cooling to be directly supplied to the facility, which enables energy- and climate-efficient cultivation.
The Boson Energy plant is to generate 70,000 tonnes of green methanol produced from self-generated carbon dioxide and from hydrogen as well as supply an about 60,000-m2 autonomous greenhouse facility with electricity, green CO2, heat and cooling. Additionally, thermal energy will be supplied to port buildings. The water that is generated in the fuel cells is also recovered and used – in a closed cycle.
The municipality has, among other things, checked the suitable industrial sites in the areas identified in the ongoing detailed planning and design process. After all, it is benefitting from the fossil-free energy supply and sustainable jobs that will result.
One of the goals of the project is to make the transshipment port Wallhamn into the first negative-carbon ports in the world. The generation of local electricity means that all vehicles in the port will have clean charging and operation in the future. Shore power connections for ships that come in are also to be offered. Grimbrandt figures a total of 30 to 40 GWh of green electricity from hydrogen. This covers DC-DC charging of heavy-duty vessels, power for port operations and shore power connections as well as, with an energy management concept, smooth operation during load peaks.
Trash into green hydrogen
But not only Grimbrandt and Boson Energy are working to produce clean hydrogen from waste. With the technical solution of the company H2-Enterprises from New York, wastes such as plastic, sewage sludge and landfill contents are to be converted into clean hydrogen through incineration. H2-Enterprises uses an H2 thermolysis method that, at high temperatures in the absence of oxygen, converts plastics and carbonaceous waste into hydrogen and CO2.
It is a two-step process: First, steam reforming takes place, followed by the water-gas shift reaction and the separating out of H2 and CO2. At the end, the hydrogen can be further purified as needed. The captured CO2 can be used for commercial purposes or stored. Likewise, the clean H2 gas obtained from the process can be transported and stored as a liquid organic hydrogen carrier (LOHC). The green gas can be sold in this form to customers around the world – or further processed into synthetic fuels such as e-diesel or sustainable aviation fuel (SAF).
100 kg H2 from one tonne of waste
This solution almost sounds too good to be true. Because it contributes to global environmental protection from two points at once: by elimination of waste and by the production of green H2. Both are urgently needed. According to the International Energy Agency (IEA), the global demand for hydrogen in year 2030 could exceed 200 million tonnes in the desire to meet promised climate targets. In addition to reaching the sheer volume, however, the emissions-free hydrogen must also be offered at a competitive price.
On the other hand, the World Bank calculates that yearly around 2 billion tonnes of household waste accumulates that is not or only partially disposed of in an environment-friendly manner. This corresponds to about one third of the total discarded. Every minute, an amount of waste equal to the capacity of a garbage truck is dumped into the ocean. At this rate, by 2050, there will be more plastic than fish in the ocean. Already, from one tonne of waste, 100 kg of H2 can be recovered.
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