Will changing cloud impact solar power initiatives?

Hanrahan, J., Maynard, A., Murphy, S. Y., Zercher, C., & Fitzpatrick, A. (2017). Examining the Climatology of Shortwave Radiation in the Northeastern United States. Journal of Applied Meteorology and Climatology, 56(10), 2869–2881. http://doi.org/10.1175/JAMC-D-16-0420.1


A large majority of nations (146 out of 195) around the world have ratified the Paris Climate Agreement, which aims to cap average global temperatures at no more than 2°C/3.6°F above pre-industrial levels. One of the pathways to achieve that goal is incorporate more alternative energies into the world’s energy budget. Even in the United States, which has decided to pull out of the Paris Climate Agreement, 29 States, Washington D.C. and three US Territories have requirements for alternative energy according to the National Conference of State Legislators.

This leaves a bunch of different economies looking for the best way to increase alternative energy sources and invest resources like land, technology, and manpower. Large solar farms are one way to efficiently gather energy over a dedicated swath of land, but there are some hurdles. One of which is whether or not a location which has been sunny for the last 10 years will remain sunny. A recent study by researchers at Lyndon State College looked at how incoming solar energy at locations in the Northeast United States have changed and what that means for the future.


Accurate Solar Measurements Yield Accurate Power Estimates

30 years of data are needed to fully understand the natural variability of a climate system. However, most weather stations have only just started measuring solar energy within the last decade. This means that there isn’t enough data available for site surveyors to get an accurate estimate of how much electrical power can be produced at any given site.

The researchers in this study have found a way around this data hurdle. They found a relationship between the difference between the high and low temperatures during the day and incoming solar energy. A greater difference between the high and low temperatures in a day translates to more incoming solar energy. Weather stations have been measuring temperature for longer than half a century, so using temperature differences as a proxy for solar energy measurements helps extend the period of record.


More Clouds, More Problems

While analyzing the extended data record, researchers found an interesting phenomena in the northeast portion of the United States. The amount of solar energy that reaches the surface has decreased over the summer months. A summer in 1958 could have more solar energy than a summer in 2005.

How is this change in cloud cover possible? Climate change is making more clouds! Climate change has rapidly warmed the waters of the Great Lakes, which are upwind of the Northeast US. This heating causes more evaporation and more evaporation yields more clouds. Clouds reduce the amount of solar energy that makes it to the Earth’s surface.


Future Implications

The Great Lakes and surrounding areas are likely to continue to warm and produce more clouds. This could further reduce the amount of solar energy that could reach solar panels in the Northeast. Alternative energy producers must keep a location’s future energy creating potential in mind in order to meet local clean energy goals and meet demand for the future.

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Geneva Gray

Geneva Gray is a graduate student at North Carolina State University in Atmospheric Sciences. She researches climate change and applied statistical methodologies. When she isn’t writing to meet a deadline, she’s knitting something cute for her infant daughter.

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