"Solar hydropower" technology: the cost of electricity per kilowatt-hour or less than 7.2 cents
Photon Energy of the Netherlands is cooperating with Australian technology provider/project developer RayGen Resources to plan to build a
300MW/3.6GWh "solar hydro power plant" project on an unspecified 1,200 hectares of land in Australia. The project is currently undergoing
licensing and grid connection processes,and preparations are expected to be completed before the end of 2023.
The "solar hydropower station" technology developed by RayGen Resources is a new method of solar energy utilization, using the company's
proprietary PV Ultra (super photovoltaic) system and a low-cost, large-scale, long-term long-term energy storage system-thermal water power
(Thermal Hydro) system realizes cogeneration.
Figure: System diagram
The operating principle is: the heliostat used in the traditional tower solar thermal power station focuses the sunlight on the super photovoltaic
receiver on the tower, and directly converts the light energy into electric energy; at the same time, water cools the battery and indirectly generates
heat energy. . The heat storage technology is based on the temperature difference between two pools --- "hot pool" and "cold pool". The heat
generated by the photovoltaic cell on the top of the tower is injected into the "hot pool", and the electricity generated by the photovoltaic cell is
cooled by an electric refrigerator to cool another "cold pool"; it is stored by the 90°C temperature difference between the two water-based pit-type
heat storage tanks energy. When needed, heat is used to drive an Organic Rankine Cycle (ORC) engine to generate stable electricity. According to
reports, it can reach 70% charge-discharge efficiency, deep discharge, and zero degradation of the heat storage medium (water) during recycling.
"Our ultra-photovoltaic module uses a small multi-junction gallium arsenide (GaAs) solar cell with a size of only 10cmx10cm; there is a water heat
sink on the back of the battery. The ultra-photovoltaic module is 4,000 times more powerful than a typical solar panel. A typical solar panel is 0.15kW/m?,
while the ultra-photovoltaic module has higher concentration ratio, efficiency and cooling, providing 750kWh/m?. The peak optical efficiency of the
ultra-photovoltaic module installed on the solar tower reaches 85%. The current receivers have More than 400 modules can generate more than 1MW
of electricity and 3MW of heat. "Photon Energy said that electricity is directly generated, and heat is collected as a by-product of cooling panels. These
towers are 45 meters high and are similar in scale to cell phone communication towers.
For the energy storage unit, PhotonEnergy said that the organic Rankine cycle (ORC) turbines will be provided by Swedishconglomerate Atlas Copco.
(Swedish conglomerate Atlas Copco). A spokesperson for the company said: "The working fluid used in the turbines we produce boils at a temperature
below 90°C, and the industrial chiller is a standard industrial chiller."
The facility includes two insulated water-based thermal storage pits or heat accumulators. The temperature of one reservoir is maintained at 90°C,
and the temperature of the other reservoir is close to 0°C. The temperature difference of 90°C is used to generate dispatchable electricity using ORC turbines.
The LCOE of this project is estimated to be less than 7.2 cents/kWh. The spokesperson emphasized: "The specific LCOE of the technology depends on
the application, location and other factors of the project. In a market where pure solar and solar + battery projects are increasingly facing challenges,
we are demonstrating the economic return of the project-more than pumped storage. good."
RayGen's "Solar Hydropower Station" pilot project has been in operation for more than six years. In 2015, with the support of the Australian Renewable
Energy Agency (ARENA), Raygen developed a 250kW pilot project in Newbridge, Victoria. In 2018, with the support of ARENA and the New Energy
Employment Fund of the Victorian Government, Raygen installed two more 250kW ultra-photovoltaic systems to expand the NewBridge project.
The total capacity is about 1MW.
On October 18, 2021, RayGen announced the end of the company's A$55 million Series C financing (June 2021 raised US$42 million, October raised
US$13 million). RayGen's strategic shareholders mainly include Equinor Ventures, AGL Energy, Photon Energy Group, Schlumberger New Energy and
Chevron Technology Ventures. The funds from the C round of financing will be used for the construction of the Carwarp project, as well as the
development of a 100MW production line and one or more 1,000+MWh projects.
At present, the Carwarp project is progressing smoothly, 20% of the construction progress has been completed, and it is planned to be put into
operation in July 2022. It will be connected to the 22kV transmission line and enter the Red Cliffs terminal station, and will be able to provide stable
renewable energy at a price of less than US$100/MWh. The project will demonstrate the combination of two innovative technologies (super-photovoltaic
and thermal water power) to improve the economics of solar + energy storage, while providing increased security and reliability of the power grid.