Supplying zero-carbon energy to entire districts
An increasing number of building projects are now incorporating an energy supply based on hydrogen and fuel cells. Given the targets set out in the Paris climate agreement, the current thinking is clearly to avoid designing new housing developments that are dependent on fossil fuels and instead switch entirely to renewables. Due to the high expense that is sometimes associated with innovative energy technology, it makes sense to maximize the number of users. Residential neighborhoods in particular, which may run from several dozen homes to a hundred properties, are one way of making this alternative approach worthwhile.
Since early 2020, the city of Esslingen in Germany has been in the process of creating an urban district that will have virtually zero impact on the climate. Built on the 30-acre (12-hectare) site of a former freight station, Neue Weststadt will be the location for 450 residences as well as office and commercial buildings. All properties in the development are due to be supplied by a future-proof energy system – as will be the new buildings that will form part of Esslingen university. Situated not far from the current railroad station, the construction of a new campus is underway, due for completion in 2025, which will incorporate lecture theaters, seminar rooms, offices, a canteen, a computer suite and a library.
This research project, dubbed the “climate-neutral quarter,” should be finished in 2022. According to the proposals, excess power from the building’s integrated photovoltaic system (1,700 kWpeak) will be used to generate green hydrogen on site that can then be supplied to properties or made available for transportation or industrial applications. If required, hydrogen gas can also be converted back into electricity in the planned combined heat and power (CHP) plant or fed into the natural gas grid.
A notable feature of this scheme is that, here, hydrogen production (400 kgH2 a day) will not take place on some industrial park or greenfield site, but right in the middle of this city quarter. This means that waste heat from the 1 MW electrolyzer can be utilized concurrently to heat surrounding buildings.
The hydrogen tank, weighing in at just under 9 metric tons, was delivered to site at the end of November 2020. Felix Mayer, project manager at the developer Green Hydrogen Esslingen, explained: “The weight is due, in particular, to the 0.5-inch (1.2-cm) thickness of the tank’s stainless steel wall. The tank needs this in order to withstand the high number of load cycles as the pressure increases and decreases.”
Mayer added: “The tank can hold 30 kilograms of hydrogen. That doesn’t sound very much but the specific energy density of hydrogen is extremely high. For example, a full tank is equivalent to 1,000 kWh in terms of its heating value. The connected CHP plant can run for more than two hours on a full tank and this means, for instance, that the 167 housing units in Block D can be provided with energy, and a few more homes besides.”
Because this initiative is being funded by the German economy and education ministries, Norbert Fisch opted for an engine-driven CHP unit from Germany rather than a fuel cell power plant from Japan since he wanted to keep German taxpayers’ money in the country. If the latter option had been chosen, Fisch has admitted, the power to heat ratio of the fuel cell would have been around 10 percent higher.
In summer 2019, operating company Green Hydrogen Esslingen GmbH, established in March 2019, received first prize in the startup category for its city quarter concept as part of the Sustainability Challenge run by the German Sustainable Building Council.
Creating a hydrogen district in Gütersloh
A comparable project is also taking shape in the German city of Gütersloh. Entrepreneur Dimotrios Tassikas is making plans for an entire hydrogen district named “H2 Revier.” The Avenwedde area is the proposed location for a total of 120 housing units, divided into single-family and multifamily homes, in addition to childcare facilities as well as a complex offering commercial premises and office space. The district will be supplied with clean energy through the use of fuel cells. The businessman founded a company specializing in property development back in 2019 – Tassikas Immobilien.
Joining the project is BEN-Tec, which is overseeing the technical aspects as well as project planning and finance. According to its calculations, roughly 370 kilograms of hydrogen will be required on a daily basis – 290 kilograms for the buildings and 80 kilograms for the refueling station. Sebastian Niehoff, director of BEN-Tec, informed H2-international that both the nursery and the business complex are to be supplied with 100 percent hydrogen. The Rheine-based company is already in contact with a heating appliance manufacturer that intends to provide a suitable heating unit by the end of the year.
The 7.9-acre (3.2-hectare) area of land on Avenwedder Straße, which is owned by the Tassikas family, will be supplied entirely by renewable energy, with biogas, solar power and wind power being sourced from plants nearby, according to the plans. Any excess capacity would be used to generate hydrogen by means of electrolysis, explained Ben Blomberg, spokesman for the project. The gas, which would be produced away from the residential area, will be stored on site, for example in several gas cylinder racks, and can be used in the planned hydrogen refueling station in order to “close the loop,” in other words to tie in mobility applications as well as power and heat. And a buyer for the hydrogen gas has already been found.
Anke Buschmaas, director of logistics company Spedition Buschmaas which is located in the immediate vicinity of the development, told H2-international: “When I heard about the plans for H2 Revier, straight away I was interested in the filling station. I’m actually planning to include hydrogen-fueled trucks in my fleet as soon as possible. As my vehicles and I travel a lot across the region, and if the range is adequate, I would always be able to rely on this filling station so the fact that there isn’t an extensive supply network wouldn’t be problem. I think hydrogen is the future and I’d like to make transport as environmentally friendly as possible.”
… Read more in the latest H2-International e-Journal, Feb. 2021