Can climate change impact solar reliability?

With Australia’s renewable energy transition well underway, UNSW Sydney researchers have predicted that climate change could impact the reliability of solar, affecting generation capacity and the management of the electricity grid.

Under a warmer climate, the researchers predicted changes in the availability of solar across different regions of Australia. The findings, published in Solar Energy, have implications for future solar power infrastructure development in Australia.

Australia is a hotspot for solar, with several notable large-scale grid-connected solar power systems — or solar photovoltaics (PV) plants — in operation or development. The sensitivity of solar power generation to weather-induced variability can limit its ability to deliver a consistent and dependable energy supply.

It is possible to use proper forecasting, power storage and load controls to manage inherent variability in solar energy generation, brought about by factors such as cloud cover, seasonal cycles and location. However, if left unmanaged, it can lead to power deficits that can result in outages or complete grid failures.

According to Shukla Poddar, lead author of the study and Postdoctoral Research Fellow at the School of Photovoltaics and Renewable Energy Engineering, modelling future changes in solar availability is crucial for maintaining stable power generation as Australia’s reliance on large-scale solar grows.

“As the climate warms, managing these weather-induced power fluctuations will be a growing challenge, so we need modelling to help better predict and prepare for these changing dynamics,” Poddar said.

The researchers used regional climate model simulations to map changes in Australia’s solar resources distribution and variability under a high-emissions scenario, which is the climate trajectory Australia is currently tracking.

They found that in regions of Eastern Australia, solar reliability may increase by 2099. In particular, solar resource density, or irradiance, is expected to increase slightly, with fewer intermittent or lull periods and more clear sky days per year.

However, the findings suggest that in West Australia, solar reliability will decline over the same period with a slight decrease in availability, while intermittent periods may also increase. Episode length — the consecutive periods when solar is highly feasible for power generation — was also projected to decline, with the number of clear sky days also decreasing.

As part of the study, the researchers completed a future solar resource assessment of the SunCable and New England solar farms in Australia.

In the Northern Territory, SunCable is developing the largest solar farm in the world, which will supply renewable energy to domestic and international markets. The New England solar farm, the second largest in Australia, is also under construction and will generate a significant amount of energy for New South Wales once completed.

The researchers found that in future, the New England solar farm site will have favourable conditions to generate optimum PV power due to its East Australia location, whereas the SunCable farm may experience an increase in intermittency issues in the future, suggesting a need for more energy storage systems and forecasting.

Merlinde Kay, Associate Professor and co-author of the study, said, “Understanding the reliability of future solar generation can inform the design of these large-scale solar PV sites — where they should expand development and where they might need to invest more in storage technologies.”

According to the researchers, further studies are needed to determine how to complement solar PV in Australia with other renewables, especially as more weather extremes are likely to occur.

According to Kay, the next step would be conducting a synergy study on how wind energy can complement solar in a future warmer climate. Hybrid systems can be advantageous for generating consistent energy supply.

“We also need to look at how disruptive extreme events, such as bushfires, will impact renewable energy generation and grid operation moving into the future, given they’re likely to increase in frequency and intensity,” Kay said.

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