Picea 2 relies on lithium instead of lead

Picea 2 relies on lithium instead of lead

HPS presents new product generation

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.

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.

Author: Niels Hendrik Petersen

Exploiting phase transition

Exploiting phase transition

Innovative cooling concept for fuel cells

Hydrogen fuel cell systems have significant advantages over established technical solutions for both motive and stationary applications. They are set apart particularly by their qualities of zero-emission operation, long life and high achievable efficiencies. However, their relatively high purchase price often deters potential users. To reduce costs, bipolar plates intended for mass-production are to be designed with as little material as possible. Thanks to an innovative cooling concept, applications can be made not only less expensive but also smaller and lighter.

Reducing the installation space increases the power density of the system and raises the heat flow density. This creates huge challenges when it comes to efficiently controlling the temperature of fuel cell systems. In addition to established air and liquid cooling solutions, cooling that occurs through the change in the coolant’s state is an approach that shows much promise. By purposefully configuring the geometric surface properties of bipolar plates, greater amounts of heat can be dissipated while also enabling a targeted adjustment of the temperature distribution along the bipolar plate. The HZwo:FRAME joint project entitled “Innovative cooling systems for fuel cells” has successfully managed to develop a cooling concept based on the phase transition of a coolant and to demonstrate its function on a laboratory scale.

Greater heat transfer needed

Effective and precise control of temperature is vital for the efficient operation of a fuel cell system. Commercially available fuel cell stacks currently offer two cooling methods: air cooling and liquid cooling [1].

Air cooling is characterized principally by its simplicity of design. The technical complexity is much lower compared with liquid-based cooling systems since no other elements are required aside from a fan. Its possible uses are limited chiefly by the relatively small quantity of heat that can be dissipated. Furthermore, air-cooled systems commonly lead to highly uneven temperature distribution within the fuel cells which can negatively affect their efficiency and long-term stability. Most stacks with a power output of under 5 kilowatts are actively air-cooled, for example in stationary applications.

Liquid cooling has established itself as the prevalent form of temperature control in fuel cell stacks with a total electrical output of more than 5 kilowatts, for instance in vehicles. In liquid-cooled fuel cell systems, the coolant is pumped around a circuit through special cooling channels which are integrated into the fuel cells. The heat that is absorbed here must then be transferred back to the environment in a downstream heat exchanger.

Current developments are increasingly focused on thin metal bipolar plates as this type of plate lends itself to future mass production at favorable cost. At the same time, the power density of fuel cells can be increased, thus opening up new application areas and creating possibilities for miniaturizing fuel cell systems. Given this shift in development, the aforementioned conventional cooling solutions, based on convection alone, will be insufficient in future to dissipate the necessary amount of heat via the surface areas that remain.

Two-phase cooling (also referred to as evaporative cooling) makes it possible to reach the high heat flow densities required, i.e., the flow of thermal energy relative to the unit area and cooling time for miniaturized fuel cells. This cooling process exploits the effect whereby a large amount of energy – the latent heat of evaporation – is needed when the coolant changes into a gaseous state. This energy is extracted from the fuel cell during the phase transition on the surface of the bipolar plates, thus helping significantly to cool the fuel cell. Since this powerful cooling concept relies on low volume flows of coolant, the output required from the necessary peripheral equipment, such as pumps, can be reduced considerably when compared with air or liquid cooling [2].

Laser cutting

The research was motivated particularly by the huge potential that evaporative cooling offers in terms of the efficient heat management of fuel cell systems. Here, the attention was focused on metal bipolar plates since they are a key functional element in the fuel cell. As part of the development process, design concepts for the new cooling method had to be devised and implemented, such as the simulation-based calculation of optimized coolant flow or the design of durable gaskets. In the end, it was decided to produce the metal bipolar plates from a 100-micron-thick initial sheet using forming techniques and to then modify the plates to meet the requirements of the new cooling concept.

One project objective was to achieve a homogeneous temperature distribution on the bipolar plate. To reach this goal, a suitable surface functionalization was chosen as the method for influencing the heat transfer coefficient. This technique was applied by introducing microstructures in the form of single-pulse laser cuts using laser beam machining. The effect of these kinds of microstructures is, firstly, to enlarge the real surface area of the bipolar plate and, secondly, to increase the number of nucleation sites for bubble formation during the phase transition.

In connection with this, the microstructure density (number of microstructures per unit area), because of its relevance as a design parameter, was investigated by varying the spatial gap between the individual pulse cuts. Abb. 1 shows the results of microstructuring the test pieces at different pulse gaps of between 5 microns and 35 microns.

Proven at lab level

A laboratory testing area was developed and set up to examine the heat transfer of the modified bipolar plates (see fig. 2). The test fixture was designed so that the technical conditions would correspond to those of a real-world application and could be altered within a range of realistic load variations. A transparent process chamber and a bipolar plate envelop the cooling channels, thus enabling visual identification of flow and boiling processes occurring in the coolant. In addition, three shielded thermocouples were positioned centrally in the direction of flow and spaced evenly across the bipolar plate. These were used to measure the temperature distribution in the coolant.

Fig. 2: Test fixture: process chamber with integrated bipolar plate and temperature sensors

The experiments used different types of plate, including a stamped reference bipolar plate and a laser-structured, coated bipolar plate. The microstructure density was varied depending on the direction and length of flow in order to achieve the most even temperature distribution possible along the direction of flow.

Fig. 3: Structured bipolar plate with microstructure density reducing in the flow direction (left); detailed view of wave structure (center); detailed view of microstructuring (right)

The test fixture was used to run experiments to demonstrate and investigate the influence of surface functionalization on phase transition behavior. Here, the boiling processes on the structured surface were less distinctive than on the unstructured reference plate (see fig. 4). In addition, the measurements using the temperature sensors confirmed that the maximum temperatures arising could be lowered through surface functionalization of the bipolar plate. What is more, the temperature distribution along the direction of coolant flow was much more even: The temperature ∆T along the structured and coated plate was lower for all parameter sets examined in comparison with the reference bipolar plate.

Fig. 4: Results of the visual examination: intensity of bubble movement (dark-blue areas) in the flow field of the reference plate (top) and the structured and coated plate (bottom) for the process parameters (incoming coolant temperature and heat flow density of the bipolar plate): 78 °C and 0.5 W/cm2 (left); 78 °C and 2 W/cm2 (right)

It was thus possible to prove that the thermodynamic properties of bipolar plates, particularly in the evaporation zones, can be influenced and modified through microstructuring. The project’s findings represent a further step toward achieving fuel cell stacks that are both cost-effective and space-efficient.

About the project

The project gathered essential and relevant knowledge for the design and technical realization of a fuel cell stack with metal bipolar plates based on the evaporation principle. The work was validated under realistic conditions. The following project partners worked in cooperation to achieve the project objectives: WätaS, Fischer Werkzeugbau, CeWOTec, the Department of Micromanufacturing Technology and the Department of Advanced Powertrains at TU Chemnitz.

Funding and project management: European Regional Development Fund (EFRE) / Sächsische Aufbaubank (SAB)

[1]        A. Fly and R. H. Thring, A comparison of evaporative and liquid cooling methods for fuel cell vehicles, Int. J. Hydrogen Energy, vol. 41, no. 32, pp. 14217–14229, 2016, ISBN: 0360-3199, ISSN: 03603199, DOI:10.1016/j.ijhydene.2016.06.089
[2]        G. Zhang and S. G. Kandlikar, A critical review of cooling techniques in proton exchange membrane fuel cell stacks, Int. J. Hydrogen Energy, vol. 37, no. 3, pp. 2412–2429, Feb. 2012, ISSN: 03603199, DOI:10.1016/j.ijhydene.2011.11.010

Igor Danilov, M. Sc,
Dipl.-Ing. (FH) Ingo Schaarschmidt, M. Sc,
Dr.-Ing. Philipp Steinert,

Clean hydrogen from waste and plastic

Clean hydrogen from waste and plastic

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.

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.

Hydrogen emergency response

Hydrogen emergency response

EU projects reveal need for new safety measures

The results of the European Union’s HyResponder and HyTunnel-CS projects have been awaited with great anticipation. Numerous experts from industry, the fire service and research institutes been involved in these initiatives over the past few years, tasked with tackling the issue of fires and accidents connected with hydrogen applications. Now the International Fire Academy, the IFA, writes: “Hydrogen vehicles in tunnels: great danger for emergency response personnel.”

The publication of Germany’s national hydrogen strategy saw the German government set out a framework for action for the future production, transport, use and reutilization of hydrogen and related innovations. Hydrogen can make a significant contribution to mitigating climate change – as a fuel for cars, a feedstock for industry or a fuel for heating systems. A multifaceted energy carrier, it can be applied across all sectors and therefore has a key role to play in the energy transition.

In power-to-gas plants, a carbon-neutral process is employed to produce green hydrogen using renewable energy, allowing this energy to be stored effectively in the gas grid and carried onward. Hence its proponents are suitably upbeat about the technology.

However, hydrogen is – as a quick glance at the safety data sheet will tell you – a highly flammable gas and one which is now being stored and transported with increasing frequency and in ever-larger quantities. This poses a challenge for fire services and public authorities when handling approvals procedures and inevitably when responding to emergency situations, as the following call-out examples show:

  • Truck catches fire at a hydrogen refueling station
  • Two persons seriously injured following a hydrogen tank explosion
  • Hydrogen refueling station exploded
  • Difficult salvage operation – accident with “hydrogen vehicle”

Fire services are well used to dealing with traditional fuels such as gasoline and diesel on their rescue missions. Alternative fuels like liquefied natural gas, better known as LNG, or hydrogen have so far played only a very minor role, which is why emergency crews have fairly limited experience of them.

Now the energy transition is starting to gain momentum. Due to the conflict in Ukraine, the demand for LNG and hydrogen has risen sharply. In addition, natural gas grids are expected to convey hydrogen in the future, initially in blended form. A great deal of technical research and regulation will be needed to make it possible, and is currently being agreed and established in various committees.

This requires appropriate resources to be made available to public authorities and emergency organizations in order to handle the arrangements, train up staff and ensure the provision of special firefighting equipment.

We have observed that there are already established hydrogen applications for which fire crews often do not yet have the appropriate skills to carry out an emergency response.

HyResponder and HyTunnel-CS projects

In the past few years, the EU’s HyResponder project has developed a European Emergency Response Guide which is currently being presented at a country level. In Germany, an event took place in Oldenburg at the end of May 2023 in order to communicate the proposed hydrogen emergency responses to German firefighting experts. The same event was held in Austria in April.

The most important outcome from the European HyTunnel-CS research project, to which the IFA contributed its views from a fire service perspective, is: “Firefighters can protect themselves against smoke, heat and fire spurts, but not against the blast waves from explosions of hydrogen vehicles in tunnels. Therefore, it is vital to keep a safe distance. However, how can people be saved and fires be fought effectively? There is still no satisfactory answer to this question – although more and more hydrogen-powered vehicles are being registered. That is why the fire services need to work on suitable solutions immediately.”

Alongside recommendations from the research projects, there are other national and international means of support for emergency services, for instance ISO 17840 – the first global standard for firefighters. Knowing how the energy is stored on board a vehicle can mean the difference between a successful rescue and a possibly unexpected explosion, gas leak, shooting flame or a fatal electric shock.


Several hundred thousand users have downloaded the Euro Rescue app. It offers access to 1,400 vehicle rescue sheets in four languages. The international association of fire and rescue services CTIF is pushing its distribution and takeup.

Nevertheless, this presupposes that rescue teams are able to identify the type of vehicle. In cases of fires occurring in tunnels or underground parking lots, this is difficult to accomplish. It is this particular circumstance the IFA was referring to in the earlier quotation. This is because fire crews would proceed as usual and then suddenly happen upon a fuel cell vehicle. Even if the correct rescue data sheet is found, the information about the necessary safety distances for emergency crews in the event of a hydrogen vehicle fire can be best described as “leaving room for improvement.”

When dealing with fires and accidents, the overall scenario always has to be considered. This must include the area surrounding the rescue site and account needs to be taken of this in response planning. A fuel cell bus, for example, could be on fire at night in the parking lot because it is parked next to another burning vehicle. The hydrogen bus is not the cause here, yet it does make the scenario much more serious. Two basic situations need to be contemplated: One in which hydrogen equipment (hydrogen bus, hydrogen car) is itself the cause and the other, much more likely case where hydrogen equipment will be affected by an external event. It is essential that the approvals procedure takes both variations into consideration.

Artificial intelligence has great potential

On the other hand, new digital applications, particularly artificial intelligence or AI, are offering up possibilities for rapid information gathering in the future which could support the emergency response. The long times taken by public authorities to process approvals have come under much criticism. Policymakers are promising to speed up procedures significantly in this respect. Here too, AI can come into play and save a lot of time.

In particular, a suitable AI module can allow the fire service to quickly analyze the documents received and check plausibility. Robots and drones – with AI – can bring decisive benefits for emergency responses in explosive ranges. For example, a robot can scan an underground parking lot. Especially relevant here is the ability to identify fuel cell vehicles in underground parking lots and tunnel systems without endangering emergency crews.

One solution would be to fit vehicles that run on alternative fuels with a chip so that robots or drones are able to identify the vehicles more quickly. Measurement technology on the robot could also be used to detect leaking hydrogen.

Explosive situations cannot be practiced in real life which is why training using virtual reality or augmented reality techniques lends itself to this purpose. As Figure 3 shows, useful training for incident commanders can be carried out with regular free-of-charge programs.

Balancing act

If the fire service needs training and special resources, it doesn’t necessarily mean that the hydrogen technology is faulty or susceptible. It is the new scenarios, such as a multi-vehicle accident in a tunnel involving a hydrogen truck or bus, that are significantly increasing the risk for responders.

This is all “politically controversial” in terms of getting action, since the desired message is that hydrogen is virtually problem-free. Financial support for emergency response is “not likely” to be provided. Emergency service organizations are increasingly confronted with a variety of new technologies and fuels. Many different fuels are being used in parallel during the transitional phase. For those working in fire and hazard prevention and in incident planning, this often means they come across new situations and are learning by doing. Not only does workplace health and safety need to be ensured for staff at hydrogen refueling stations and tanker drivers but equally so for emergency crews as part of a risk assessment.

How much extra training do we want to provide our fire service members? At the moment there are still no special training facilities in Germany. The German interior minister warns of “attacks” on energy infrastructure, and violent action by activists also needs to be taken into consideration. This requires incident planning by fire services. Alternative forms of energy are “closely” linked to this: In terms of emergency response, it makes sense to exploit synergies, for example by including LNG and CNG in hydrogen training courses.


  • ISO 17840: The First Worldwide Firefighters’ Standard | CTIF – International Association of Fire Services for Safer Citizens through Skilled Firefighters
  • Petter, F.: First on site: Decision-making training for incident commanders in vehicle fires, internal study, unpublished
  • 200,000 users have downloaded the Euro Rescue app – access to 1400 vehicle Rescue Sheets in 4 languages | CTIF – International Association of Fire Services for Safer Citizens through Skilled Firefighters

Author: Franz Petter, Chief Fire Officer, Hamburg, Germany,

Fuel cell stocks on the move

Fuel cell stocks on the move


Every day, more and more encouraging stories are popping up on news tickers, saying that companies, cities, towns and entire unions of countries, such as the EU, want to step on the gas in terms of climate action, with hydrogen definitely playing a crucial role in their efforts. While people are still sparring over what production method we should focus on, I am sure green hydrogen will win out in the end. Though we may need some of that blue gas to get to green.