Fluctuations in solar radiation create challenges for solar power plants, leading to issues in the power grid and affecting reliability. A recent study by researchers aimed to enhance our understanding of temporal and spatial variations in solar irradiance across the Asia Pacific region by analyzing data from satellites. Their results offer important insights that can aid in optimizing the placement of future solar energy facilities.
In the context of the current energy crisis and the pressing challenge of climate change, harnessing renewable energy sources has rapidly become an essential global priority. Among the various options available, solar energy stands out as a promising choice; experts predict that it could emerge as our primary energy source well before the century concludes.
While solar energy has many benefits, its generation does come with certain restrictions. Similar to wind energy, solar irradiance can shift quickly due to changes in weather, which results in variations in electricity output. These variabilities pose risks to power grids and make it uncertain whether energy demands will always be met. Therefore, understanding the potential fluctuations in solar irradiance over time and space is vital for identifying the best locations for solar power plants.
With this in mind, a team of researchers, led by Specially Appointed Assistant Professor Hideaki Takenaka from the Center for Environmental Remote Sensing at Chiba University, sought to broaden our knowledge of solar irradiance throughout the Asia Pacific region. Their latest research, published online on June 13, 2024, and featured in Volume 276 of Solar Energy in July 2024, involved a comprehensive analysis of solar irradiance data obtained from geostationary satellites. Other contributors to the study included Kalingga Titon Nur Ihsan and Atsushi Higuchi from Chiba University, along with Anjar Dimara Sakti and Ketut Wikantika from the Center for Remote Sensing at Institut Teknologi Bandung.
The data utilized in their analysis was sourced from the Himawari-8 and Himawari-9 satellites, which are Japanese satellites designed to capture high-resolution images of the Asia Pacific region. The team employed AMATERASS solar radiation data, which offers quasi-real-time analysis of solar radiation, synchronized with geostationary satellite observations. This innovative system was developed by Dr. Takenaka and colleagues to accurately gauge solar irradiance using rapid radiative transfer computations and neural networks. Since its launch in July 2007, AMATERASS has continuously archived data for over 16 years, which is publicly accessible through Chiba University’s CEReS DAAC (Distributed Active Archive Center), having been downloaded over 186 million times and utilized in numerous research and national projects in Japan. By harnessing this technology, the team analyzed solar irradiance variations in spatial and temporal dimensions, specifically assessing how solar radiation differs over both time and space using a grid format of 20 km by 20 km every ten minutes.
Their in-depth analysis revealed notable insights regarding solar irradiance within the region. For instance, they discovered that areas closer to the equator display less fluctuation in solar irradiance over time compared to regions at higher latitudes, largely due to the impact of rainfall and cloud cover. Additionally, higher elevation areas showed increased variability owing to more pronounced cloud activity. Around the Tibetan Plateau, significant seasonal changes were noted in the ‘umbrella effect,’ which measures how much solar energy is reflected back into space. “Our evaluations based on spatiotemporal data revealed characteristics that would’ve been impossible to achieve using a traditional approach that relies on simple long-term averages or TMY (Typical Meteorological Year) as a standard for solar irradiance data,” Dr. Takenaka remarked.
Moreover, the research team also evaluated the performance of over 1,900 existing solar power plants using both annual and seasonal data. They found that due to the umbrella effects caused by clouds, many of these plants do not perform optimally from June to August. This indicates that areas significantly affected should not depend solely on solar power to satisfy increased energy demands during these months.
Lastly, the researchers examined the ideal layout for future solar power facilities, concluding that spreading solar energy production across a wider area is more effective than focusing efforts in a single location. “Considering the spatial and temporal nuances of solar irradiance, it is our recommendation that rapid fluctuations in solar power output could be minimized by distributing smaller photovoltaic systems over a broader area instead of concentrating on large solar power plants,” Dr. Takenaka explained. “It’s important to note that these findings are based on weather and climate studies, rather than an engineering viewpoint.” One practical approach to achieving this model might be through the installation of rooftop solar panels, which has been gaining traction in numerous countries.
Overall, the conclusions from this study will inform both the immediate and future strategies for solar energy production in the Asia Pacific region, enhancing sustainable energy technologies and supporting efforts to combat climate change.
