First ‘solar hydro’ system connected to the grid, 17-hour storage component imminent


Melbourne company RayGen has connected its 4 MW PV Ultra towers at Carwarp, in Victoria’s northwest. The connection marks the launch of one of two systems in Australia’s first ‘solar hydro’ power plant which has promised to deliver some of the country’s deepest and lowest cost storage.

Global supply chain challenges, RayGen said, have pushed out the expected timeline for the accompanying 3 MW / 50 MWh electro-storage system, but the company is confident it will be fully operational and delivering up to 17 hours of storage to the National Electricity Market (NEM) by the first quarter of 2023.

Once operational, the company expects to be able to provide the Commonwealth’s Low Emissions Technology stretch goal of firmed renewables for under $100 / MWh. The project will be delivering that storage to Victoria’s West Murray region, which is notoriously congested causing numerous renewables projects in the region to be curtailed.

RayGen’s tech & supporters

Based in Melbourne, RayGen’s proprietary PV Ultra solar towers and electro-thermal energy storage technologies have received backing from major players in the last years, including becoming a focus for Dutch renewables company Photon Energy Group. 

It has also been backed by Australia’s largest electricity “gentailer” AGL Energy, Norwegian oil company Equinor, Schlumberger New Energy and Chevron Technology Ventures. 

How the technology works is by focusing sunlight with a field of aligned mirrors, or heliostats, onto a tower-mounted receiver containing an array of PV Ultra modules made of gallium arsenide PV cells. Around one third of incident sunlight is directly converted into electricity by the PV cells, while the remaining two thirds is captured in the form of heated water, used to actively cool the modules during operation.

The heat extracted from the PV Ultra modules is then stored in two insulated water reservoirs with a 90°C temperature difference. The ability to co-generate electricity and heat, the latter a captured by-product, makes the facility highly efficient.

RayGen’s Newbridge pilot site in operation

Image: RayGen

In total, each PV Ultra receiver contains approximately 400 PV Ultra modules, each generating 2.5 kW of electricity and 5 kW of heat. This produces 1 MW of electricity and 2M W of heat per field setup.

Carwarp project

The initial timeline for the Carwarp project to be fully commissioned was mid-2022, but the cold water pumping system was held up in Shanghai due to Covid-19 lockdowns.

For the time being, the project will be delivering solar electricity into the NEM with the company saying it expects the last remaining storage components to be delivered in the next fortnight.

Once complete, the storage system will also participate in wholesale energy and Frequency Control Ancillary Services (FCAS) markets once operational.

RayGen heliosat

Australian Renewable Energy Agency

Both Carwarp and RayGen’s 1 MW pilot project in Newbridge, Victoria, have been partially funded by the Australian Renewable Energy Agency (ARENA), which allocated $15 million to Carwarp.

The project is wholly owned by RayGen and has an operational design life of 30 years.

South Australian project

Working with Photon Energy, RayGen’s technology is also planned for deployment in a major project in South Australia. The proposed SA project would have a total solar generation capacity of 300 MW with a grid connection capacity of 150 MW. The target energy storage capacity is 3.6 GWh, equivalent to 24 hours of full load, to the grid, from storage.

Photon, which entered a strategic partnership with RayGen in 2020 and in 2021 made a $3 million equity investment in in the company, said it has already secured 1,200 hectares of land for the project but as of late last year had not revealed the specific location.

Photon plans to build a large-scale facility in South Austraia using the Raygen technology.

Image: Raygen

Solar hydro at Liddell

AGL Energy has previously said it it will assess whether RayGen’s technology could be installed at its Liddell facility, a major coal-fired plant in New South Wales scheduled to be fully decommissioned by April.

Just yesterday, AGL and Fortescue Future Industries upped their vision for Liddell, revealing they are looking to install up to 2 GW of capacity there to support the planned hydrogen hub.

AGL this year shut the first of four generating units at its Liddell Power Station.

Image: AGL Energy

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