China CSP tower hits 89% output rate; CSP tower to supply Italian pasta factory

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China's Delingha CSP hits 89% fulfilment in first year

Supcon Solar achieved a fulfilment rate of 88.6% at its 50 MW Delingha CSP tower plant in Qinghai Province in the first full year of operation, industry association China Solar Thermal Alliance (CSTA), reported September 29. This is higher than the CSP fulfilment rates of 70 to 80% set out in many global EPC contracts.

Total annual output at Delingha was 121.8 GWh, compared with a projected 137.5 GWh, Jin Jianxiang, Supcon Chairman, reportedly told CSTA.

One of the first large-scale CSP tower projects in China, Delingha includes seven hours of thermal energy storage (TES) and is located at an altitude of 3,017 meters, next to a Supcon 10 MW pilot project.

Supcon developed the 50 MW plant and supplied the main technology and engineering procurement construction (EPC) services. The plant reached full load in April 2019 and started commercial operations in September 2019. The latest output data refers to July 2019-July 2020, the first full year of regular operations.

Equipment failure, a lack of operational experience and grid curtailments were the main drivers of lost production, Jianxiang said.

In August 2019, the plant was shut down or at limited load for almost a month, reducing output by around 7 GWh. In July 2020, an outage of the steam turbine for over a week cut output by around 2.2 GWh.

More minor faults occurred in the cold salt pump, solar receiver and steam generation system, reducing output by around 0.8 GWh. Weather issues or insufficient operating experience cut output by around 4.8 GWh. Grid curtailments clipped output by around 0.9 GWh.

Gains expected

In May, Jianxiang predicted the fulfilment rate for the first year of commercial operations, from October 2019 to September 2020, could exceed 100%.

Cloud coverage remains a key operational risk for Delingha. The plant can provide stable electricity during a short cloudy period, but "sudden and unexpected" clouds can impact operation and lead to system shut-down, Jianxiang said.

Cloud systems impose thermal shocks and heat fatigue on the receiver, raising safety issues and shortening the component life, he said.

Advances in cloud camera systems will boost CSP plant efficiency in the coming years, researchers say.

Supcon is now using image processing and meteorological data at Delingha, to predict cloud movement and measure the impact on the plant. This data will allow Supcon to adjust the solar field to ensure even distribution of solar energy on the receiver surface and avoid molten salt flow issues, or if a shutdown is necessary, minimize downtime.

“In the upcoming six months, we will be committed to operation optimizations, particularly in the solution of clouds," Jianxiang said.

As a result, Supcon expects the fulfilment rate to rise "significantly," he said.

Efficiency boost

Data from the first year of regular operation at Delingha show solar thermal conversion efficiency hit 56.6%, significantly higher than the design value of 52.0%, Jianxiang told CSTA. The solar to electricity efficiency hit 24.2%, compared with a design value of 22.0%

The annual operating cost was $2.3 million, equivalent to $20.9/MWh, Jianxiang said.

Labour costs represented almost two thirds of operational costs, so the estimated cost for an equivalent plant of 100 MW capacity would be below $11.9/MWh, he said.

Supcon Solar will take its learnings from Delingha to the 50 MW Minos CSP tower project in Greece, where it will supply the technology and EPC services with construction partner Energy China CGGC International.

Ceramic CSP tower plant to supply Italian pasta factory

A group of European companies including German Aerospace Centre (DLR) is to build a pilot ceramic particle CSP tower plant in the next two years to supply a pasta factory owned by Barilla in Foggia, Italy, DLR announced October 9.

The HiFlex CSP power and heat project will use DLR's ceramic particle CSP tower technology to supply electricity or industrial process heat during the day or night.

Current CSP tower plants use molten salt as the heat transfer medium (HTM) and storage media, limiting temperatures to 565 degrees C to avoid corrosion and decomposition.

DLR's centrifugal receiver concept can achieve particle temperatures of over 1,000 degrees C at the receiver outlet, boosting plant efficiency.

DLR will deliver its receiver to the site in Italy in 2021, the company said.

The HiFlex consortium includes 11 companies from seven countries. The project will receive 13.5 million euros ($15.9 million) from the European Union's Horizon 2020 research program.

Vast Solar partners with Queensland Uni on materials, O&M

Australian CSP developer Vast Solar is working with the Queensland University of Technology (QUT) to research materials and operations and maintenance (O&M) efficiency for its proposed 50 MW hybrid CSP-PV-gas plant in the mining town of Mount Isa, Vast Solar told local media.

The A$600 million ($433.1 million) North Western Queensland Hybrid Power Project (NWQHPP) would be Vast Solar's first commercial CSP project, following a 1.1 MW pilot CSP plant in New South Wales, online since 2018.

NWQHPP would integrate Vast Solar's modular sodium loop CSP technology with thermal energy storage, PV, battery and gas-fired generation, to provide dispatchable power day and night.

Vast Solar is working with O&M and advanced materials teams at QUT that are funded by the Australian Solar Thermal Research Institute (ASTRI).

The O&M team has already developed techniques to predict the soiling rate of solar mirrors, assess the impact on plant performance, and optimise cleaning activities. The advanced materials group will tackle challenges in material compatibility.

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