Climate change could mean fewer sunny days for hot regions banking on
solar power

Date:
October 7, 2020
Source:
Princeton University
Summary:
Changes to regional climates brought on by global warming could
make it so that areas such as the American Southwest that are
currently considered ideal for solar power would be less viable in
the future, a new study suggests. Higher surface temperatures will
lead to more moisture, aerosols and particulates in the atmosphere,
which may result in less solar radiation and more cloudy days. The
study is the first to assess the day-to-day reliability of solar
energy under climate change.



FULL STORY ========================================================================== While solar power is a leading form of renewable energy, new research
suggests that changes to regional climates brought on by global warming
could make areas currently considered ideal for solar power production
less viable in the future.


========================================================================== Princeton-based researchers recently published in the journal Nature Communications the first study to assess the day-to-day reliability of
solar energy under climate change. The team used satellite data and
climate models to project how sunlight reaching the ground would be
affected as warmer global temperatures alter the dynamics and consistency
of Earth's atmosphere.

Their study found that higher surface temperatures -- and the resulting increase in the amount of moisture, aerosols and particulates in the
atmosphere -- may result in an overall decrease in solar radiation and
an uptick in the number of cloudy days. Hot, arid regions such as the
Middle East and the American Southwest -- considered among the highest potential producers of solar energy -- were most susceptible to greater fluctuations in sunlight, the researchers found.

"Our results could help in designing better solar power plants and
optimizing storage while also avoiding the expansion of solar power
capacity in areas where sunlight intermittency under future climate
conditions may be too high to make solar reliable," said corresponding
author Amilcare Porporato, Princeton's Thomas J. Wu '94 Professor of Civil
and Environmental Engineering and the Princeton Environmental Institute
(PEI). The research was supported by the Carbon Mitigation Initiative
based in PEI.

"To use an academic metaphor, in terms of solar power, semiarid places are
now like students who get an A nearly every day," Porporato said. "Now,
climate change is disturbing the usual dynamics of the atmosphere and
the regularity of the solar radiation reaching the planet's surface. We
tried to quantify how much more often those A's could become B's, or
even C's, as a result." Existing research on how solar energy will
fare in this irregular future has largely focused on average levels of sunlight, said first author Jun Yin, a researcher at Nanjing University
of Information Science and Technology who worked on the paper at Princeton
as a postdoctoral research associate with Porporato.



==========================================================================
"The novelty of our approach was to point out that in some places there
is going to be more uncertainty in day-to-day variability," Yin said. He
and Porporato previously reported that climate models underestimate the
cooling effect of the daily cloud cycle. They worked on the most recent
paper with co- author Annalisa Molini, an associate professor of civil infrastructure and environmental engineering at Khalifa University in
the United Arab Emirates.

The researchers' findings were based on probabilistic calculations similar
to those used to determine the risk of flooding or drought. The reduced reliability of solar energy is related to the increased variability
of atmospheric moisture and aerosols in some arid regions. Higher
temperatures hold more moisture and are more turbulent, which favors
the formation of clouds and keeps particles in suspension longer,
Porporato said.

"Then there is the issue of soils drying, which may be even more
important," Porporato said. As temperatures and atmospheric turbulence
increase in arid regions such as the Middle East, dry soils potentially
lead to greater amounts of dust and atmospheric aerosols that would
diminish solar radiation. These trends are in fact already detectable
in observations from climate-observation networks, Porporato said.

For the American Southwest, the researchers' findings were less
consistent.

Some models showed more solar radiation and lower intermittency
in the future, while others showed less solar radiation and higher intermittency. These results illustrate the challenge of trying to
predict the reliability of solar energy in an uncertain future, Yin said.

"We hope that policymakers and people in the energy industry can take
advantage of this information to more efficiently design and manage photovoltaic facilities," Yin said.

"Our paper helps identify efficient solutions for different locations
where intermittency could occur, but at an acceptable level," he said. "A variety of technologies such as power storage, or power-operation policies
such as smart curtailment, load shaping or geographical dispersion, are promising solutions." To follow up on their work, the researchers plan
to examine climate persistency -- specifically, the number of consecutive
sunny or cloudy days -- which is important for solar power. They also are exploring how clouds could affect the effectiveness of tree planting as
a climate mitigation strategy. Trees absorb not only carbon dioxide but
also solar energy, which would raise surface temperatures. A resulting
increase in cloud coverage could change current estimates of how effective trees would be in reducing atmospheric carbon.


========================================================================== Story Source: Materials provided by Princeton_University. Original
written by Morgan Kelly.

Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Jun Yin, Annalisa Molini, Amilcare Porporato. Impacts of solar
intermittency on future photovoltaic reliability. Nature
Communications, 2020; 11 (1) DOI: 10.1038/s41467-020-18602-6 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201007123029.htm

--- up 6 weeks, 2 days, 6 hours, 50 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1337:3/111)