🔍
Why don’t we cover the desert with solar panels? - Dan Kwartler - YouTube
Channel: TED-Ed
[6]
Every day, the sands of the Sahara Desert
reach temperatures up to 80° Celsius.
[12]
Stretching over roughly
nine million square kilometers,
[15]
this massive desert receives about
22 million terawatt hours of energy
[21]
from the Sun every year.
[23]
That’s well over 100 times more energy
than humanity consumes annually.
[29]
So, could covering the desert with solar
panels solve our energy problems for good?
[35]
Solar panels work when light particles hit
their surface with enough energy
[39]
to knock electrons
out of their stable bonds.
[43]
On their journey back to stability,
these electrons produce electricity.
[47]
However, there’s a limit to how much power
panels can generate.
[52]
Solar panels can only interact
with certain wavelengths of light,
[55]
making it impossible to convert
over half the sunlight they receive.
[60]
And even light particles they can convert
often bounce off them
[64]
without ever hitting an electron.
[66]
But thanks to clever scientists
and engineers
[69]
and substantial government investment,
[71]
solar panels are generating
more electricity than ever.
[75]
Anti-reflective coatings and patterns
on the panels’ surface
[79]
create more opportunities for incoming
light particles to hit electrons.
[83]
These techniques have increased commercial
solar panel efficiency
[88]
from the low-teens to 25%,
[91]
with experimental models reaching
up to 47%.
[95]
What’s more, solar has gotten
89% cheaper over the last decade,
[99]
thanks in part to global supply chains
for other technologies
[103]
that use the same materials.
[105]
Together, these factors have
made solar power
[108]
the cheapest source of electricity
on Earth.
[112]
Countries including India, China,
Egypt, and the US,
[115]
have already taken
these new panels into the desert.
[119]
Their massive solar farms range
from 15 to 56 square kilometers,
[124]
and when the sun is high in the sky,
[126]
these plants can provide energy
[128]
for hundreds of thousands
of local residents.
[131]
But these farms also get
extremely hot.
[134]
Light that solar cells don’t convert
or reflect is absorbed as heat,
[139]
which reduces a panel’s efficiency.
[142]
And the cooling systems employed by many
farms can use huge amounts of energy
[146]
powering fans or moving water
to maintain optimal temperatures.
[151]
Even with these systems, solar panels
in the desert absorb far more heat
[156]
than the natural sandy environment.
[159]
This hasn’t been a problem
on the scale of existing solar farms.
[162]
But if we tried to cover the Sahara,
[164]
this effect could create massive changes
in the region's climate.
[169]
Constructing solar farms already
disrupts local ecosystems,
[173]
but a plant of this scale could
dramatically transform
[177]
the desert landscape.
[179]
Thankfully, solar panels
aren’t our only option.
[183]
And some of the largest solar plants
in the world are trying a new approach:
[187]
giant mirrors.
[189]
Morocco’s Noor Power Plant,
[192]
which will eventually cover roughly
30 square kilometers of the Sahara,
[195]
is a concentrated solar power plant.
[199]
This design reflects light
onto a receiver,
[202]
which converts that energy to heat,
and then electricity.
[206]
These mirrors still create a dangerous
temperature shift for local wildlife,
[210]
but they have less potential
to transform the landscape.
[214]
And since it takes time for the materials
being heated to cool off,
[217]
these plants often continue producing
electricity past sunset.
[223]
Whether they use panels or mirrors,
[225]
industrial solar farms are often easy to
fit into existing energy infrastructure.
[230]
However, getting their electricity beyond
local power grids is much more difficult.
[235]
Some countries are working on ways to
connect electric grids across the globe.
[240]
And many farm store energy
in massive batteries,
[243]
or convert their electricity
into clean gas that can be used later.
[247]
But right now, these techniques are still
too expensive and inefficient to rely on.
[253]
Worse still, industrial renewables
can share some of the same problems
[257]
as fossil fuels,
[258]
relying on destructive mining operations
and carbon-emitting global supply chains.
[264]
Fortunately, solar can
exist on many scales,
[268]
from industrial solar farms
to smaller installations
[271]
that power individual buildings
and rural communities.
[275]
These projects can supplement energy use
or provide a passive source of energy
[279]
for regions off the grid.
[281]
And since solar panels rely
on a few simple components,
[285]
they’re quick to install
and relatively easy to update.
[288]
In fact, it’s this flexibility
that enabled solar
[292]
to become so cheap and ubiquitous
over the last decade.
[296]
So if we want to keep up with humanity's
rising energy use,
[300]
we'll need answers both big and small.
Most Recent Videos:
You can go back to the homepage right here: Homepage