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  • 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 coursealgorithm 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.

The Saharan Desert, and North Africa at large, is one of the world's greatest untapped

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The Problem with Solar Energy in Africa

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    joey joey に公開 2021 年 10 月 29 日
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