The goal for the "Gas, Service and Rest Area of the Future" on the A9 highway near Munich was to generate more energy per year than it needs to operate. The assessment as an "Energy Plus Standard with more than 10% surplus” is based on the balance calculated according to primary energy. None of the on-site available energy for mobility is included.
The energy concept developed for this purpose uses synergy effects between the secondary energy carriers, electricity and hydrogen. 1320 kWp Photovoltaic modules (PV) convert sunlight into renewable solar electricity across an area of more than 7,100 m² / 76,424 ft², mostly from the tops of the carports and along the noise barrier wall. Excess electrical energy is temporarily stored on-site. This is done with Li-ion accumulators and - as a special feature in this model project – as hydrogen gas (power-to-gas). Hydrogen (H2), produced from water by electrolysis, is stored in a low-pressure gas tank. H2 is a clean energy carrier: its combustion i.e. oxidation releases only water, neither greenhouse gases nor other harmful particles. As an alternative to a battery, this "green" hydrogen, produced on-site by regenerative PV electricity, is another energy storage. When needed, a specially adapted fuel cell cogeneration system silently reconverts the hydrogen into water, generating electricity and heat. At the same time, the locally produced hydrogen is available as an innovative fuel for the future-oriented H2 mobility after increasing the pressure to over 800 bar. The entire hydrogen plant and its technology was designed and delivered by Linde AG.
Transsolar carries out an accompanying monitoring for heat, cold and electricity. This points out that the energy objectives of the project in the second year of operation are fulfilled and proves the negative CO2 balance: The surplus of renewable electricity exported to the public grid (with its electrical power produced as a blend by conventional and renewable resources, German: “Strom-Mix”) results in a CO2 credit which is higher in comparison to the debit of energy import across the plants boundary of both, electricity and natural gas.
In the annual energy balance, the „Fürholzen West Gas, Service and Rest Area of the Future“ is more than self-supporting its operation: its energy export to the grid additionally avoids global emissions each year that equal 27 t of CO2, which would be emitted while generating electricity in a corresponding quantity using all the sources, conventional and renewable, “mixed” for the usual current in the German grid.