Source:pvmagazine
A group of researchers in China has investigated the impact of weather-related extreme low-production (ELP) events on the global PV system fleet across various regions and has found that more investments could be necessary to ensure the effectiveness of the systems.
“Our results highlight the critical need to prepare for ELP events, which present greater challenges than conventional power gaps,” the scientists emphasized. “Characterized by prolonged durations or high intensities, ELP events can lead to power shortages that exceed the capacity of conventional reserves, especially in some regions with dense PV installations where high-intensity events of long duration have occurred.”
The research team analyzed daily PV power generation on a global scale in the 1986-2021 period through the ERA5 tool, which provides hourly estimates of a large number of atmospheric, land and oceanic climate variables. It then identified nine types of ELP events based on intensity and duration and analyzed event frequency and the total number of low-production days for each type.
The academics defined an ELP day as a day where PV power output is lower than 90% of all days in the observation period and an ELP event as a sequence of consecutive days where electricity production is below 10%.
The analysis, which did not include residential PV systems, showed that areas with higher solar power generation potential tend to register low or medium-intensity events, while areas with relatively poor PV power generation potential are generally more exposed to high-intensity events. It also showed, however, that most of the world's PV installations are located in areas with poor PV power generation potential and are consequently significantly affected by weather variability.
“Our results reveal that regions between 60°N and 60°S experience an average of 27 ELP events annually, with 17% of these events being high-intensity,” the researchers stressed. “Regions with dense PV installations—including Southern China, Central and Northern Europe, Central and Eastern America, and Japan—are particularly affected. These areas, which collectively host approximately half of the global PV installations, see 44% of ELP events being high-intensity.”
They also found that PV systems located in these regions are exposed to a 2.7 times higher frequency of high-intensity events than the global land average.
As a mitigation strategy to reduce the impact of ELP events on PV power generation, the team suggested using a daily backup supply for each site, while integrating PV resources with wind energy and hydropower. “Besides, transmission infrastructure and on-grid connections offer potential solutions for reducing ELP events, especially for countries with numerous dispersed PV installations, as the likelihood of extreme weather simultaneously impacting multiple regions is significantly lower,” it explained.
The academics also warned, however, that implementing these strategies could be expensive, as they may require upgrading technology and long service periods. “Maintaining a daily backup supply equivalent to the average event intensity could recover 39% to 81% of events across different sites,” they emphasized.
Their findings are available in the paper “Photovoltaic installations are extensively deployed in areas at risk of extremely low production,” published in Communications Earth & Environment.