New research into the future impacts of a warming world suggests global solar power output could become more unpredictable in the future, as higher temperatures lead to more cloudy weather in some parts of the world.
In a paper published in the journal Nature Sustainability, a team of researchers from the University of Santiago, Stanford University and Japan’s Chiba University, have predicted that warming global temperatures could lead to greater solar intermittency due to changes in the frequency of cloudy days.
The researchers found that changes in global cloud patterns could increase the variability of solar output, by increasing the frequency and longevity of cloudy days in some of the sunniest parts of the world, including Australia and the Arabian Peninsula.
The researchers modelled future climates based on two different future scenarios; a scenario where global greenhouse gas emissions are stabilised and warming is limited to around 1.8 degrees by the end of the century, and a second scenario where emissions continue to track on their current trajectories, and the world warms by around 3.7 degrees.
The researchers found that climate change would impact solar output differently in some parts of the world. Changing weather patterns could see some regions increase solar output due to fewer cloudy days, while others could be substantially impacted by lower solar power generation by an increase in cloud frequency.
Under the more extreme scenario, where emissions continue relatively unabated, the effects would be amplified further with significant changes in cloud variability being fuelled by higher average temperatures.
Crucially, the researchers highlight that their findings point to increases in the variability of solar output, and that global warming could increase the uncertainty of solar power. Warmer temperatures would contribute to more cloudy days with low solar output and therefore would place a greater strain on energy systems and networks, increasing the need for investment in back-up supplies of power.
“Although our results confirm that average PV energy yields are expected to change to only a minor to moderate extend, they highlight the fact that these relatively modest changes mask significant shifts in the number of warm cloudy days – days with relatively low PV power outputs,” research co-author Sarah Feron said.
“In our new study, we have shown that significant increases in the frequency of warm cloudy conditions are expected in large regions of the world by mid-century. Increases in the number of cloudy days may boost the weather variability and in turn the PV power intermittency.”
The findings suggest that a rapid and substantive response to climate change, including the wide-scale adoption of solar power, could ultimately help solar power play a more meaningful and predictable role in a future decarbonised energy system.
A lacklustre response to climate change could jeopardise the ability of technologies like solar power to serve as an effective alternative to fossil fuels in the future.
“Future climate will change the frequency of weather conditions that lead to very low PV power outputs,” the research paper says. “These changes are a source of uncertainty that may complicate energy planning and compromise investments in the energy sector in the near future. While a drop in cloudiness, for example, may improve the network reliability, an increase in warm or cloudy conditions may boost very low PV power outputs during short periods of time, affecting the network stability.”
“We have shown that substantial increases in the frequency of weather conditions that lead to very low PV power outputs are expected in large regions of the world by mid-century. Generally driven by more clouds, conditions leading to poorer PV power outputs can be reinforced in some low-latitude regions by increasingly extreme temperatures.”
For the Arabian Peninsula, a region that has an exceptionally high level of available solar resources, it could see a doubling of cloudy days by the end of the century. Likewise, the United States could see a 30 per cent increase in low solar days, while Western Europe could benefit from a reduction in cloudy days.
For Australia, the researchers found that the effects would be relatively small, with a negligible impact in summer months and a predicted increase, albeit small, in solar production in winter months.