Global dimming is the phenomenon of decreasing the amount of sunlight reaching the Earth’s surface due to various factors, such as air pollution, aerosols, clouds, and volcanic eruptions. Global dimming has been observed since the 1950s, and it has significant implications for the climate, the environment, and the renewable energy sector. In this blog, we will explore how global dimming affects solar energy generation in the UK, and what can be done to mitigate its impact.
What is the Evidence of Global Dimming?
According to various studies, global dimming has reduced the amount of solar radiation by 4-20% globally between the 1950s and the 1990s12. The effect varies by region, but some of the most affected areas are Europe, North America, and Asia, where industrialization and urbanization have increased the levels of air pollution and aerosols. Global dimming can also be influenced by natural events, such as volcanic eruptions, which can inject large amounts of sulphur dioxide into the atmosphere, blocking some of the sunlight. For example, the 1991 eruption of Mount Pinatubo in the Philippines lowered the global temperature by about 0.4°C for over a year3.
Global dimming can be measured by various methods, such as using ground-based instruments, satellites, or models. One of the sources that you provided is a spreadsheet from the UK government that shows the monthly and annual values of solar irradiance in the UK from 1929 to 20234. The data is based on measurements from the Met Office network of stations, and it shows the variability and trends of solar radiation over time. The spreadsheet also provides some graphs and tables that illustrate the data.
How Does Global Dimming Affect Solar Energy Generation?
Solar energy generation depends on the amount and quality of sunlight that reaches the solar panels. Global dimming reduces both the quantity and the quality of solar radiation, which affects the performance and efficiency of solar systems. According to a study by the University of Reading, global dimming reduced the potential solar energy output in the UK by 19% between 1960 and 20055. The study also estimated that global dimming cost the UK solar industry about £500 million in lost revenue over that period.
Global dimming can also affect the reliability and predictability of solar energy generation, which can pose challenges for grid integration and management. Solar energy is an intermittent and variable source of power, which means that it depends on the weather and the time of the day. Global dimming can make the solar output more uncertain and fluctuating, which can increase the need for backup power and storage systems, as well as smart grid technologies, to balance the supply and demand of electricity.
What Can Be Done to Mitigate the Impact of Global Dimming?
Global dimming is a complex and multifaceted problem, which requires a combination of solutions at different levels. Some of the possible actions that can be taken to mitigate the impact of global dimming are:
- Reducing air pollution and greenhouse gas emissions, which are the main causes of global dimming. This can be done by implementing stricter environmental regulations, promoting cleaner and more efficient energy sources, and encouraging behavioural changes among individuals and businesses.
- Improving the design and operation of solar systems, which can enhance their resilience and adaptability to global dimming. This can be done by using more advanced and robust solar technologies, optimizing the orientation and tilt of solar panels, and applying coatings or filters that can reduce the effects of dust and aerosols.
- Developing and deploying more grid-scale and distributed energy storage systems, which can store excess solar power when the sun is shining, and release it when the sun is dimmed. This can improve the stability and flexibility of the grid, and reduce the dependence on fossil fuels and other backup power sources.
- Investing in more research and innovation, which can improve the understanding and monitoring of global dimming, and develop new and better solutions for solar energy generation and integration.
Conclusion
Global dimming is a serious and widespread issue that affects the amount of sunlight reaching the Earth’s surface, and consequently, the solar energy generation potential. Global dimming has reduced the solar output in the UK by a significant amount, and it poses challenges for the solar industry and the grid. However, there are ways to mitigate the impact of global dimming, such as reducing air pollution, improving solar systems, developing energy storage, and supporting research and innovation. By taking these actions, we can ensure that solar energy remains a viable and sustainable option for the UK and the world.
Global dimming chart – Source Gov.uk
| Calendar period | 20-year mean [note 5] | 2020 average | 2021 average | 2022 average | 2023 average [provisional] | 2020 deviation | 2021 deviation | 2022 deviation | 2023 deviation [provisional] | |
| January | 1.8 | 1.8 | 1.4 | 2.6 | 2.4 | -0 | -0.4 | 0.7 | 0.6 | |
| February | 2.8 | 2.7 | 2.6 | 3.1 | 3.2 | -0.1 | -0.2 | 0.2 | 0.3 | |
| March | 4.1 | 5.2 | 3.8 | 5.7 | 2.5 | 1.1 | -0.3 | 1.7 | -1.6 | |
| April | 6.1 | 7.8 | 7.6 | 6.4 | 5.5 | 1.7 | 1.6 | 0.3 | -0.6 | |
| May | 6.6 | 9.7 | 5.6 | 5.8 | 7.3 | 3.1 | -1 | -0.8 | 0.7 | |
| June | 6.5 | 6.2 | 6.3 | 7.7 | 8.2 | -0.4 | -0.2 | 1.2 | 1.7 | |
| July | 6.4 | 5.6 | 6.1 | 7.2 | 5.2 | -0.8 | -0.3 | 0.8 | -1.2 | |
| August | 5.7 | 5.2 | 4.4 | 7.9 | 5.4 | -0.5 | -1.3 | 2.2 | -0.3 | |
| September | 5 | 5.4 | 4.6 | 4.4 | 5.2 | 0.4 | -0.4 | -0.6 | 0.2 | |
| October | 3.3 | 2.2 | 3 | 4.2 | 3 | -1.1 | -0.2 | 1 | -0.2 | |
| November | 2.3 | 2.1 | 2.4 | 2 | 2.4 | -0.2 | 0.1 | -0.3 | 0.1 | |
| December | 1.7 | 1.6 | 1 | 1.9 | 0.9 | -0.1 | -0.7 | 0.2 | -0.7 | |
| January-March | 2.9 | 3.3 | 2.6 | 3.8 | 2.7 | 0.3 | -0.3 | 0.9 | -0.3 | |
| April-June | 6.4 | 7.9 | 6.5 | 6.6 | 7 | 1.5 | 0.1 | 0.2 | 0.6 | |
| July-September | 5.7 | 5.4 | 5 | 6.5 | 5.3 | -0.3 | -0.7 | 0.8 | -0.5 | |
| October-December | 2.4 | 2 | 2.1 | 2.7 | 2.1 | -0.4 | -0.3 | 0.3 | -0.3 | |
| January-December | 4.4 | 4.6 | 4.1 | 4.9 | 4.3 | 0.3 | -0.3 | 0.6 | -0.1 |
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