In the Middle East, India and China,
migratory dust coats solar panels
... and dust in the air blocks
incoming solar energy too.
Researchers in India
who cleaned their solar panels
every few weeks discovered
an immediate 50% jump
in efficiency after each cleaning.
92% of the dust on each panel
was natural, but the 8%
human made particles
are smaller and stickier
-- so the 8%
human-emitted-dust
blocked as much solar energy
as the 92% natural dust.
Pollution and natural dust
will slow the clean-green-energy
future in India and China
unless we get auto-cleaning panels.
Solar panels work best
when clean, near the equator,
not under too many clouds,
and when electricity demand
peaks at 12 noon
... which no modern country does.
Global solar energy production
is taking a big hit due to
air pollution and dust.
According to a 2017 study,
airborne particles and
their accumulation
on solar cells are
cutting energy output
by more than 25%
in certain parts
of the world.
The regions bit hardest
are also those investing
the most in solar energy
installations:
China, India and the
Arabian Peninsula.
The study appeared online
in Environmental Science
& Technology Letters.
“My colleagues in India
were showing off some
of their rooftop solar
installations, and I was
blown away by how dirty
the panels were,”
said Michael Bergin,
professor of civil
and environmental
engineering at
Duke University
and lead author
of the study.
“I thought the dirt
had to affect their
efficiencies, but there
weren’t any studies
out there estimating
the losses. So we put
together a comprehensive
model to do just that.”
With colleagues at the
Indian Institute of
Technology-Gandhinagar
and the University of
Wisconsin at Madison,
Bergin measured
the decrease in
solar energy
gathered by
the solar panels
as they became
dirty over time.
The data showed
a 50% jump in efficiency
each time the panels
were cleaned after
being left alone
for several weeks.
8% of the grime
was carbon and ion
pollutants from
human activity.
“The human made particles
are also small and sticky,
making them much more
difficult to clean off,”
said Bergin.
“You might think
you could just clean
the solar panels
more often, but the
more you clean them,
the higher your risk
of damaging them.”
Grimy buildup
on solar panels
isn’t the only thing
blocking sunlight
— ambient particles
in the air also have
a screening effect.
The NASA GISS
Global Climate Model
already accounts
for the amount
of the sun’s energy
blocked by different
types of airborne particles
and estimates the amount
of particulate matter
deposited on surfaces
worldwide.
The resulting calculations
estimated the total loss
of solar energy production
in every part of the world.
While the United States
has relatively little
migratory dust,
more arid regions
such as the
Arabian Peninsula,
Northern India
and Eastern China
are looking at heavy losses
— 17% to 25% percent
or more, assuming
monthly cleanings.
If cleanings take place
every two months,
those numbers jump
to 25% or 35%.
The Arabian Peninsula
loses much more solar power
to dust than it does
human made pollutants,
Bergin said.
The reverse is true
for regions of China
and India.
This work was supported
by the US Agency for
International Development
and the Office of the
Vice Provost for Research
at Duke University.
Source:
Bergin, M.H., Ghoroi, C., Dixit, D., James Jay Schauer, Drew Shindell. (2017) Large reductions in solar energy production due to dust and particulate air pollution. Environmental Science & Technology Letters, 2017; DOI: 10.1021/acs.estlett.7b00197
PS:
Let me add the following problems that
would reduce solar panel efficiency:
(1) Moss growth in humid areas,
(2) Bird doo doo,
(3) Hail storms, and possibly
(4) Juvenile delinquents with rocks !