RayGen connects flagship Carwarp solar to grid

Solar heliostats at RayGen's Carwarp flagship project (AGL)
Solar heliostats at RayGen's Carwarp flagship project

Australian solar-storage technology company RayGen has successfully connected its flagship site in Carwarp, Victoria, to the grid, supplying renewable energy to the West Murray Grid Zone.

RayGen’s 4MW PV Ultra towers at Carwarp, approximately 36km south of Mildura, has begun delivering electricity to the National Electricity Market (NEM).

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The milestone comes as demand estimates for Long Duration Energy Storage (LDES) to replace ageing coal assets continue to pile up. It also comes despite global supply shortages delaying entire construction timelines for solar and storage projects.

While global supply chain challenges have pushed out the expected timeline for Carwarp’s accompanying 3MW/50MWh electro-storage system, RayGen is confident the project will be fully operational and delivering long duration storage to the NEM by Q1 2023.

The Australian Energy Market Operator (AEMO) estimated in its 2022 Integrated System Plan (ISP) that the NEM will need approximately 46 GW/640GWh of dispatchable storage by 2050. AEMO noted the more coal-fired generation is turned off, the greater the need for deep storage.

Meanwhile, according to McKinsey analysis for the Long Duration Energy Storage Council, 85-140TWh of LDES global capacity will be needed to achieve net-zero emissions power grids by 2040. The report estimated up to $4.3 trillion would be needed.

RayGen’s solar-storage technology helps meet this challenge by starting with a PV Ultra system that collects heat and electricity from a field of mirrors. The heat is generated by cooling the photovoltaic PV Ultra modules mounted on towers, then stored as hot water in a thermally insulated reservoir at around 90°C.

The electricity is primarily used to power a chiller that cools water in a second reservoir at near 0°C. When thermal storage energy is needed, the temperature difference between both reservoirs powers a heat-to-power engine known as an organic Rankine cycle (ORC) that delivers stored energy to the grid.

Energy in the reservoirs can be stored for as little as one to hundreds of hours. Any excess energy from the PV Ultra system can also be exported into the grid.

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The initial timeline for Carwarp to be fully commissioned was mid-2022. However, international supply chain disruptions caused a delay of the site’s thermal storage system coming online. In particular, the cold water pumping system was held up in Shanghai due to COVID-19 lockdowns, while Russia’s invasion of Ukraine disrupted shipping for components from Europe.

The last remaining components for Carwarp will be delivered in the next fortnight. RayGen is confident Carwarp will be fully operational by Q1 2023.

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