Prepare to have your mind blown.
Every hour of every day, enough of the Sun’s energy strikes the Earth’s
surface to power the entire world for a year.
For any numbers enthusiasts watching,
that’s 430 quintillion joules striking the earth every single hour.
Yes, that's 18 zeros.
With numbers like that, it's no wonder solar is viewed by many as the go-to energy alternative
to avoid the coming climate catastrophe - but despite our best efforts to develop efficient
photovoltaic panels and locate them in areas where we can maximise their potential, day always gives
way to night, and there are always going to be days where the sun simply doesn't shine.
We have plenty of them in the UK.
In a world where the stability and reliability
of the grid is critical in fully transitioning to renewable energy,
an ancient technology that once helped the Greeks destroy a fleet of Roman warships
is now being used to overcome the limitations of traditional solar power.
Before we go on, we just want to clarify that
despite the sinister title of this video, South Africa
isn’t actually developing solar powered heat-rays, but the technology behind the country’s largest
new solar power plant does have its origins in an ancient battle over 2,000 years ago.
Let's rewind.
At the height of the Second Punic War,
Rome was looking to secure its hold over the strategically placed island of Sicily
- so doing what Rome did best, they laid siege to the port city of Syracuse for over a year,
and while they were ultimately victorious, the locals didn't make it easy for them.
Inside the city a clever old man by the name of Archimedes
was developing ways to fend off the attackers -
the most diabolical involved positioning soldiers with highly polished shields on
the walls of the city and using them to focus the sun’s rays towards approaching warships,
igniting them and sending them to the bottom of the Mediterranean before they could reach land.
While the scientific accuracy of this story has since been debunked,
the concept is largely the same as that behind South Africa’s largest renewable energy project -
the 250-metre-tall, 6.5sqkm Redstone Solar Thermal Power Plant.
Using a type of solar technology known as concentrated solar power (or CSP)
the plant will use thousands of heliostats.
They’re movable mirrors that focus the sun's rays onto a central point,
generating temperatures of up to 565ºC - enough to liquify salt -
and they use that molten liquid to drive a heat engine and generate electricity.
Sitting in the highly irradiated Northern Cape Province
- where the average temperature is 26ºC all year round -
the plant will generate 100MW of electricity,
or enough to power 200,000 homes and eliminate 440 metric tonnes of CO2 emissions each year.
If that isn't enough, concentrated solar power has
a massive edge over direct solar energy production.
It removes the irregularities that can result from adverse weather
and that perpetual day-night cycle that limits the output of traditional photovoltaic panels.
By generating electricity using the sun’s heat rather than direct sunlight - as is the case with
photovoltaic power - this type of solar can be harnessed long after the sun goes down by storing
the molten liquid in tanks and releasing it at night, often when it's needed most.
This essentially eliminates the imbalances - or duck curve - that traditional solar power creates
over a 24-hour period - whereby alternative power plants have to constantly monitor and adjust their
output to avoid overloading the grid when solar power ceases production as the sun sets each day.
But what about storage batteries, I hear you say?
Well, while large-scale battery storage has gone
some way to reducing these peaks and troughs in places like South Australia,
large-scale electricity storage isn't as simple as charging your mobile power bank
and installing the infrastructure required adds significantly to a project's initial cost,
compromising its overall viability.
While the increasing efficiency of traditional photovoltaic panels
and their ability to be deployed on a small scale has seen them outcompete CSP since the 1980s,
the reliability that CSP plants offer has gained significant ground in recent years,
and installed capacity has grown tenfold between 2004 and 2013.
South Africa is among the world leaders in this type of technology.
Redstone had faced delays since 2016 and it looked like it was going be scrapped all together
following the bankruptcy of the developer SolarReserve in 2020.
But the South African government’s drive to transition towards renewables energy
saw the country sign a USD $10BN deal with Saudi Arabia
for investment into the republic’s energy sector, reviving the project.
Construction of the USD $715M scheme was announced in May 2021
following financial backing from ACWA Power.
That’s the company behind Noor I in Morocco - Africa’s largest CSP.
Commercial operations are now set to begin in late 2023.
Redstone’s revival in the wake of near financial ruin shows just how
critical government support for these projects is.
It isn’t the largest or most concentrated CSP on the continent, but South Africa’s push to
make this project a reality - and its role as a regional power - sets the country up to use
its influence to encourage its neighbours to develop their own renewable projects
and meet their own growing energy needs.
We’re betting that Archimedes didn’t expect to play such an important role
in the global energy transition when he drew up his anti-Roman heat-ray 2,000 years ago.
If you enjoyed this video and want to learn more about where construction is headed,
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