By Josh Perry, Editor [email protected]
Researchers at the Graz (Austria) University of Technology (TU Graz) Institute of Hydraulic Engineering and Water Resources Management designed a hot-water pumped storage hydropower plant that stores and supplies electricity, heat and cooling energy as needed and with zero emissions.
Franz Georg Pikl from the Institute of Hydraulic Engineering and Water Management is researching the future of global energy supply. (Staudacher - TU Graz)
According to a report from TU Graz, the system is based on three elements. The first is pumped storage hydropower, which is a century-old technology but that has been refined using subterranean tunnels to create the elevation difference between the reservoirs of water.
Heat accumulators store the thermal energy. Water, the report explained, has a high specific heat capacity and is used as a thermal energy storage medium for the underground power plant. “Thermal energy is stored and used by means of heat exchangers installed in the underground reservoirs,” the report said. “When demand for heat is high, it can be supplied directly to consumers via district heating transmission lines.”
The third element to the system is an integrated district cooling model using absorption chillers. Hot water drives the chillers to produce cooling energy that can be distributed to customers. The report added, “To ensure a constant supply of cooling energy to various temperature zones, this system can be modified by cooling the water of the underground pumped storage hydropower scheme.”
Researchers claim that the system is 80 percent efficient for electricity and thermal storage with the same level of resource consumption. This system also allows renewable energy infrastructures to be bundled with the energy grid.
“The ecological aspects of the project also make it an attractive proposition: zero-emission operation is possible, no open spaces are required and the energy storage respectively power plant does not affect the natural water balance, which in turn reduces the environmental impact,” the report concluded.
The next step is to enlist energy suppliers and industry partners to explore the construction of a prototype system.
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