The Saharan Desert, and North Africa at large, is one of the world’s greatest untapped
energy resources. The solar energy that strikes the surface of this desert has the potential
to power the entire world, a single solar panel placed here, in Algeria, is capable
of generating 3 times more electricity than the same panel, placed in Germany. [1]
What was once a geographic disadvantage, the scorching sun of these desolate lands could
now provide an economic boom for these historically impoverished nations.
A panel in a solar farm located here, 1 square metre in size, would on average generate 5
to 7 kWhs of energy each day. Increase that to 1 square kilometre and we are generating
5 - 7 Gigawatt hours of energy each day. Increase that to 1000 square kilometres and we are
generating 5-7 Terawatt hours of energy each day.
Enough to satisfy nearly 100% of Europe’s energy needs. [2] Multiply that by 10, and
we are generating 50-70 Terawatt hours a day. Enough to power the entire world. [3]
This is an impressive and often repeated statistic. [4] Napkin calculations that draw a drastic
new vision of the world. A solar powered Eutopia. Plans have even been drawn up to transform
the simple mathematics into a reality, but reality has a way of interfering with futuristic
pie in the sky calculations like this. Every plan to turn this dream into a reality has
failed. In this episode we are going to learn why.
Transporting electricity out of these remote regions is the first challenge. Currently
there are only two interconnections connecting North Africa to Europe. Both are located between
Morocco and Spain.
Two 700 Megawatt interconnections. One completed in 1998 and the second completed in 2006.
With a third connection expected to be completed sometime before 2030, for a total of 2100
Megawatts. [5]
If we wanted to transport enough electricity to power Europe, ignoring transport losses
and storage issues, we would need 592 to 831 more of these 700 Megawatt interconnections.
These aren’t just simple cables that we lay between countries. They are incredibly
complicated and expensive pieces of infrastructure. The third interconnection joining Morocco’s
and Spain’s grids is estimated to cost 150 million dollars. An enormous investment that
will see both countries footing half the bill.
592 more of these connections would cost, at an absolute minimum, 8.9 billion dollars,
and that number was found by simply multiplying 150 million by 592, but these connections
are the shortest route to Europe from North Africa. They are going to be the cheapest
to build. To build a truly interconnected grid we are going to need even longer interconnections,
connecting Tunisia to Sicily, Algeria to Sardinia and onwards to Northern Italy, Libya to Crete
and onwards to Greece and Turkey and to the rest of the Middle East Network, all the while,
building enough internal interconnections in Europe to facilitate the passing of the
solar parsal northwards, while Wind is traded south.
This plan will take billions to complete. Yet, even with these issues, European leaders
have drawn up plans to connect North Africa and the Middle East to Europe, they believe
the costs can be recovered.
Desertec is, or perhaps more appropriately was, a German led initiative centred around
a half trillion dollar investment fund [6] that would invest in generation and transmission
infrastructure across North Africa and the Middle East.
55 Billion was allocated to increasing transmission capabilities across the Mediterranean. [6]
This investment would go into both high voltage alternating current transmission over shorter
gaps, like those from Morocco to Spain and high voltage direct current over longer distances.
There is a critical distance where high voltage alternating current transmission does not
make sense.
If we plot transmission losses per kilometre for AC and DC transmission, it would look
something like this, with DC losing less power per kilometre. [7] However, in order to convert
our regional AC grid power to DC for these long distance transmission cables, we need
expensive transformers and converters. If we instead plot cost versus distance, counting
in this infrastructure. It would look something like this, and we can see that the DC and
AC lines cross each other around the 500 to 800 kilometre mark. [8].
This is the break even point where DC becomes more cost effective. So, lines connecting
Morocco directly to Spain, which spans only 28 kilometres, don’t make sense for high
voltage direct current. While longer lines connecting Tunisia to Italy will likely be
high voltage direct current lines.
Transmission losses for High Voltage DC is about 3% per 1000 kilometres and Germany’s
capital is only 1,800 kilometres from Tunisia. [9] Transmitting power, with this much investment
money, is perfectly feasible. The technologies exist. So let’s move into the generation
part of the Desertec plan.
Desertec was formulated with concentrated solar power in mind, which works very differently
to photovoltaic solar panels. Concentrated solar power facilities would be spread out
along the borders of the Sahara and Arabian Deserts.
One such facility already exists in Morocco and it’s the largest concentrated solar
power plant in the world.
It is massive, with 3 separate sections, Noor 1, 2 and 3, each using slightly different
variations of concentrated solar power, combining to provide the 510 MegaWatts.
Noor 1 and 2 are both trough based systems that use parabolic mirrors with a tube located
in the mirror's focal point. The tube contains a synthetic oil which collects the heat from
the 500,000 parabolic mirrors spread out over 308000 square metres. This oil becomes extremely
hot, as high as 400 degrees celsius, which allows it to boil water in a heat exchanger
to drive a steam turbine, which provides electricity for the grid. The 400 degree oil is also hot
enough to melt salt in a molten salt heat storage system. The molten salt heat storage
system of Noor 1 can store enough heat to keep the plant operational for 3 hours while
Noor 2 has enough storage for 7 hours. However this salt solidifies at 110 degrees and if
that happens, the plant won’t work in the morning, so Noor 1 and 2 need a fossil fuel
burning system to keep all the working fluids of the system at minimum operating temperatures
over night and to keep the oil system pumping. This fossil fuel burning system can also keep
the plant operation as a reliable baseline energy source. Removing the need for separate
natural gas peaker plants. [10]
Noor 3 does not use these parabolic mirrors and instead uses a tower system. It’s this
striking circular facility to the north. It looks less like an industrial facility and
more like a new age burning man art installation. This design allows Noor 3 to rid itself of
the oil, plumbing and pumps of Noor 1 and 2, and instead it uses mirrors arranged in
concentric circles around a central tower. The mirrors are then controlled to focus light
on a single point on the tower, which directly heats the molten salt, which is the working
fluid instead of an oil based system. The solar concentration here is much higher and
in turn, the temperatures attained are much higher. With the water being heated to 550
degrees.
This allows the tower based system to use more efficient steam turbines and using molten
salt as the working fluid removes the need for a oil to molten salt heat exchanger in
the heat storage system [11] Noor III is the world’s only operating tower based concentrated
solar power system with molten salt storage, after 2019’s shutdown of Nevada’s Crescent
Dunes plant.
The Crescent Dunes plant ceased operation in 2019, after only 4 years of operation.
[12] NV Energy broke it’s purchasing contract with the plant after it failed to meet performance
requirements. Being marred by maintenance issues, including an 8 month shutdown due
to a leak in the molten salt tank. Even when fully operational [13], the plant's electricity
cost 135 dollars per megawatt hour while a nearby photovoltaic plant was managing 30
dollars per megawatt.[14] And here lies the crux of the issue.
Concentrated solar power cost per megawatt was extremely competitive with photovoltaics
in 2009, but in the last decade photovoltaics have become obscenely cheap. Concentrated
solar power simply cannot compete in a market like this, and the same can be seen for Noor
1, 2 and 3.
However, they are currently being measured on a metric called levelized cost of electricity,
which is an average of the costs to generate electricity over the entire life of the plant.
However, this does not factor in the cost of storage for photovoltaics, which is often
just an inherent benefit of concentrated solar thermal power. So going forward, the industry
should be using a combined cost of storage and cost of electricity metric. Yet…. (this
bit needed to lead into next paragraph)
The most recent addition to this solar farm is Noor 4, a solar panel farm contributing
73 Megawatts. With the rise of cheap solar panels Desertec, contrary to what you may
expect, was doomed for failure.
Concentrated solar thermal power, by nature, needs a lot of land. The plant has a minimum
viable operating temperature, and to achieve that we need enough mirrors to reflect that
light. Solar panels do not have this problem. Solar panels can be fitted on top of homes,
over car parks or even in farmers fields to help shade plants that need shade. We don’t
need massive plots of land to make them work.
And because they are so cheap, it’s perfectly feasible to build smaller solar farms in Germany,
and avoid those transmission losses, and not incur the massive financial risk of investing
billions into a country that is not your own. That’s particularly important because a
lot of investors are very hesitant to put money into these often volatile countries.
We need to look no further than the 2013 attack on a BP natural gas plant in Algeria, to see
why this would be considered a risky investment in many parts of North Africa.
“It’s a vital economic resource for Algeria, yet it sits isolated in the midst of a vast
desert. That’s a transit root for Al Qaeda in North Africa, no wonder it was so difficult
to defend and such a tempting target for the militants.”
This is exactly why Germany is instead investing in its own domestic photovoltaic generation,
and in 2020 solar power accounted for 10% of Germany’s power generation. [15]
This idea of European countries drawing natural resources from Africa to benefit its own economy
has some undeniable problematic historic parallels. Any foreign investment like this is going
to come with some guarantees of supply for Europe. Beyond the difficulties of organizing
cross border cooperation like this, that’s not going to go down well when the country
hosting these plants needs that power for their own grid. To grow their economy or simply
stabilize their own grid for current needs. It becomes even more problematic when we consider
the amount of water these facilities need for cooling, for the steam turbine and to
keep the mirrors clean.
This facility in Morocco uses 2.5 to 3 billion litres of water every year, taking water from
a dam 12 kilometres away. [16]
Morocco is already susceptible to droughts, so scaling these water demands up, just to
feed Europe’s power needs, while taking water away from the farms that feed Moroccan
citizens, is even more problematic. To truly scale this power generation, some technological
improvement that reduces the consumption of water would be needed, or just pair the facilities
with desalination plants and use the extra water, if any, to irrigate local farms to
boost local economies even more.
For this dream of turning the Earth’s barren deserts into energy generation centres to
come true, it has to be a grassroots movement. Not some new age imperialism megaproject that
comes with a whole host of guarantees in exchange for the nearly half trillion dollar investment.
North Africa is one of the hardest hit regions in the world by climate change, with desertification
and water scarcity becoming a serious issue. This plan, despite its surface level good
intentions, sought to exploit these countries that have suffered most as a result of Western
Industrialisation. We don’t need to look for proof that this was their intention. The
moment the technology developed to allow European countries to provide their renewable power
needs within their own borders, the plan disintegrated. This plan was never about helping African
nations.
But, the idea isn’t dead in the water. These countries do have the natural resources to
benefit from solar energy. Morocco is in the best position to lead by example.
It’s proximity to Spain allows relatively short interconnections to the European grid.
It’s government is relatively stable compared it’s North African neighbours with a political
stability index of minus 0.33. Algeria, Tunisia, Libya and Egypt are all much lower and while
Morocco has abundant solar resources, it also benefits from consistent desert winds along
its coast.
Morocco has the potential to invest in its own energy needs, while exporting excess to
Europe. Leading by example. Slowly shifting away from being a net energy importer of fossil
fuels, and becoming an energy exporter. Local infrastructure to benefit local people first.
An African nation using its resources to benefit itself first and foremost. The potential for
Africa’s solar energy future is undeniably. The technologies to facilitate cross border
energy trading exist, and investments are happening to increase capacity for trade with
this 3rd interconnector between Morocco and Spain, funded equally by both sides, ensuring
a level playing field.
Figuring out the best practice for growing and improving electricity is incredibly complicated.
Electricity grids are effectively the largest machines on the planet. Hundreds of generators
scattered across countries connected together by wires, relays and switches. The task of
managing that by hand and making sensible decisions for a single human is impossible,
and more and more of the grid infrastructure is turning towards a smart grid, controlled
by algorithms. Battery farms employ coding and mathematics experts to develop algorithms
to allow them to buy and sell the electricity they store to maximize profit, and those jobs
are some of the best paying and highest demand in today’s world.
Learning about algorithms and coding like this is an invaluable skill and whether you
are a highschool student or experienced engineer Brilliant is a great place to start learning
and brushing up your skills. I recently started the interactive course “algorithm fundamentals”
and learned a tonne of useful and insightful information. This is just one of many computer
science courses on Brilliant that will help you not only understand, but enjoy the information
you are learning. With continual assessment to test your knowledge, but critically don’t
impede your progress when you get something wrong, instead each answer comes with a detailed
explanation of the solution, because the best way to learn is to try, and sometimes learn
through failure.
If learning a valuable skill sounds like something you want to do. Go to brilliant.org/realengineering/
and finish your day a little smarter. And the first 500 of you to do so will get 20%
off the annual subscription to view all problems in the archives.
If you are looking for something else to watch right now, we have a two part hour long series
about my favourite airliner, the 787 below. Or you could watch Real Science’s video
about the insane biology of the Axolotl.