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Should we solar panel the Sahara desert? (bbc.com)
48 points by e15ctr0n on Dec 31, 2015 | hide | past | web | favorite | 60 comments

We should not be covering any wilderness (even a relatively barren wilderness like the Sahara) with solar panels until every inch of roof in the developed world is covered in solar panels. There's a ridiculous amount of flat open surface that is just wasted space right now, and not only is the space going to waste but the energy consumers exist right underneath that wasted roof space.

That's a silly notion.

I've lived in many places (Seattle, Edinburgh) where a solar panel is only useful about 25% of the year due to clouds, or the simple fact of being so far north. We don't all live in Southern California.

The Sahara presents an environment with lots of sunlight, little clouds, and nothing else being developed there. And it doesn't need to be solar panels- solar farms based on collectors reflecting to a central tower are what is being cited in the article. We can't do that in most developed areas, because it takes up a lot of space- deserts are mostly empty, perfect for that.

In short, it would make far more economic sense to build solar panels in the Sahara and lose 50% of the power to transmission loss piping it all to Scotland than it ever would to put the same solar infrastructure into Edinburgh (or many other cities in the world).

Solar panels still work in cloudy weather, though the efficiency is reduced. Transmission losses are huge over long distances, plus you would have the added problem of securing the panels and transmission lines against sabotage -- and the Sahara isn't exactly the most politically stable part of the world.

Transmission losses are huge over long distances

I found this document from ABB, http://www02.abb.com/global/abbzh/abbzh250.nsf/0/2adcc78ab7f..., they know a thing or two about power transmission. They claim:

   A 2,000-km long HVDC line rated at 800 kilovolts
   loses about 5 percent of the electricity it
   carries to heat, while an equivalent AC line
   would lose twice that amount, or about 10 percent.
I wouldn't call either of those losses "huge". There are of course additional losses in converters or transformers. Still, that's darn good, better than I would have guessed.

plus you would have the added problem...

Those are fair points, I think much more significant than the transmission losses.

...as silly as siting a CSP (concentrated solar power) system which requires copious amounts of WATER and maintenance in the middle of a desert?

CSP is dead. It actually never stood on its own.

Photovoltaics (PV) IS KING: 1. No moving parts 2. Creates electricity directly at the load (minimal losses) 3. Sunlight is the most evenly distributed resource on Earth (got clouds? Add more panels!) 4. Made from crystalline silicon (very abundant) 5. PV panels create electricity for 100+years (yes at diminishing amounts over time, but at 80% production @ 30 years of service...come on) 6. A source of power that actually has the potential to (or does, depending on the report you read) generate net positive energy in its lifetime. 7. Cheap as shit

Yes we need fossil fuel generators for smoothing out the grid as weather conditions change, but its possible to implement this now.

To produce all the energy needed by humans, only a minuscule part of the desert has to be covered - the environmental aspects would be pretty neglectable. The pro of using the Sahara would of course be efficiency, the downside are politics and transporting the energy produced to somewhere where it can be used.

Are the energy loss from transport far lower than the benefits of Saraha in terms of light input ?

A high voltage DC line should have less losses than the energy gained by moving south. Furthermore, one can pretty much rely on the Sahara sky not being clouded, which is probably more important as you then can rely on having the same energy output every day. The let-down is that it would cost billions to put the necessary lines in place. Putting the solar farms into the south of Spain is likely to be more cost-effective. The nice thing about photovoltaics though is, that there is no minimum size for a plant. This means, we could do both in parallel - extend European solar plants and set up some in Africa.

Yeah, the idea of trying on Spain and Greece seems great. Simpler politically and economically.

Every inch? Even roofs in areas with very low sunlight available for solar energy? There must be some places where solar panels on roofs is not the most economical choice for renewable energy.

Having solar at the point of use also mitigates costly upgrades to bulk transmission lines. Solar absolutely doesn't need to only used in equatorial locales to be useful. With the cost dropping so much, base load battery storage doesn't even make sense. The dominating factor for solar installations is mounting and wiring, not the panels themselves.

Let's do both.

While I agree with your sentiment the problem is that solar panels in populated urban areas that are perpetually blanketed by geoengeering spraying practices are not going to be nearly as efficient as ones in dedicated remote areas not being sprayed.

Chemtrail citation needed.

Geoengineering is undeniable don't be ignorant. Either you can't read or you are a shill.

I forgot to tell you to gfy. I will never capitulate.

Yes, capture energy there.

But don't make electricity, make hydrocarbons using the https://en.wikipedia.org/wiki/Fischer%E2%80%93Tropsch_proces...

Ship water and coal, and return with mixed hydrocarbons, then distribute them all over the world. You thermalize (rather than electrolyze) the water to get hydrogen, then react it with the carbon from the coal.

Build a large pipeline to the nearest port to transport the material rather than trucking it.

The leftover oxygen can be sold, or more likely just released.

Since hydrogen releases much more energy (per atom) than carbon when burned, and since since hydrogen outnumbers the carbon in the final product, this will greatly reduce CO2 emissions, even though it's not completely zero.

Capturing heat from the sun is much easier and cheaper than electricity.

Forget the coal, make methanol from water and co2.

What ars is saying that he wants to take the complex and partially-saturated hydrocarbons in coal and turn them into a hydrogen-satured hydrocarbon. (Most coal has a lot of double-bonds and loops within the carbon, in addition to a hydroxyl groups.) Since energy is released every time you break a bond, you'll have more bonds to break in the end product, but with the same amount of carbon, so you're keeping emissions constant while adding energy.

Regardless, it would be interesting to start with CO2 rather than coal. But can it be sucked up from the atmosphere efficiently and in mass quantities?

Well, trees have been doing it for a long time. Where do you think the carbon in the trees comes from? :)

Trees do lots of cool things that we don't know how to do. That's true of biological life in general. Heck, the lightest insulation for outdoor clothing is still feathers.

Aerogel is lighter than feathers and more insulating. There was a kickstarter this year for a jacket using aerogel as an insulator.


True. It's pretty exciting tech, although apparently it's not very comfortable or easy to work into clothing and gear. It seems pretty promising for very extreme conditions though, like climbing Everest.

Yeah, trees are annoyingly good at absorbing CO2 from the atmosphere. They have the benefits:

1. CO2 dissolves into their fluids

2. The CO2 is almost immediately next to the places that is going to use it

3. Since the Calvin Cycle is distributed, they don't have to collect and concentrate the CO2

4. A lot of surface area on the cellular level to absorb CO2.

I'm reading http://www.scientificamerican.com/article/prospects-for-dire... and it's unfortunate that "Each machine would require roughly 1.1 megajoule of electricity for pumping and compressing per kilogram of CO2 captured."

Trees have the advantage of lots and lots of them. But each individual one is not very efficient.

Making a power plant as large as a small forest is just unrealistic, and would not come close to being powerful enough.

That's why I suggested carbon from coal instead of CO2 - it's just not practical to get it from air.

All we really have to do is reduce CO2 emissions, it's not necessary to eliminate them.

> from water and co2.

It's not easy to get co2 in bulk, and methanol has no advantages over methane (for this process). You need the exact same amount of carbon.

This can't possibly be cost effective or profitable?

OP's point (I'm guessing) is that transmission is the problem with remote generation like this. Production of liquid fuels would probably be better than the enormous cost of building transmission capacity and the associated VAR and resistive losses.

Do you really think it's more expensive, in terms of energy to transport electrons over a wire than liquids over the surface of the earth? I find that hard to believe. Mind you, I haven't done the math.

Bulk transport over the ocean is extremely cheap, so much so that oil speculators are paying ships to idle in anticipation of price rise.

Electrical transmission will lose you anywhere from 1%-1.5% per 100 miles depending on the voltage you step up to. Transmitting from the Sahara to the places where the load is gets you to rather large resistive losses.

Also, there are generation losses. A traditional heliostat boiler + turbine will get you about 15-20% effficiency. then you have to shunt the waste heat somewhere in a place with very little fresh water. Oops. PV doesn't get you much better, with about 18% efficiency, but you do solve the need for coolant, at the cost of another problem: Sahara dust on your panels.

The OP talks about using the thermal output from heliostats directly, which would probably (like you, I haven't done the math) be more efficient in fuels production than 15-20%, although you do have the coolant problem again.

One of us should do the math :) Until then, my intuition is that liquid fuels production from such a remote location would probably be more efficient.

It's for sure more efficient. Just think about the power density of even a small gas pipeline - it utterly dwarfs any electrical line, and they are much cheaper to build.

People in Australia are considering a commercial plan to build a solar power to liquid hydrogen plant, possibly converting the hydrogen to LNG or ammonia, and then shipping it to Japan.


The mere fact that LNG (liquid natural gas, at -180 degrees Celsius) is already being shipped across the worlds oceans today, supports the notion you are questioning.

I think OP's point is more about storage than transmission. Yes you can transport electrons over a wire, but that has a cost and then you have a limited reachability. With liquid on the other hand, you can store in massive tanks and transport anywhere in the world to produce energy locally.

Um, that's just a fancier way of burning coal.

No it's not. The majority (by far) of the energy comes from thermalizing the water. The hydrogen-oxygen bond is much stronger than the carbon-oxygen bond and there are many more hydrogen atoms in the final fuel.

Ok, it's a more efficient way of burning coal. You're still CO2-emmision positive.

> You're still CO2-emmision positive.

And so what? I said that, did you not read what I wrote?

I'll quote it for you: "this will greatly reduce CO2 emissions, even though it's not completely zero."

> more efficient

That is way underestimating it, it's a fraction of the CO2 output of any other fuel. By far most of the energy comes from the sun, only a small amount comes from the coal. And it's pollution free since all the heavy metals in coal are captured at the source.

It also fits in well with existing technology since there don't exist any other ways of transporting fuel in bulk except hydrocarbons. There simply doesn't exist any other way of doing it.

Have you ever heard the saying "The perfect is the enemy of the good?"

Trying to be eliminate CO2 entirely is impossible, if you hold out for that you'll do nothing whatsoever.

The sahara could be a source of endless solar energy. But for the obvious political and technical considerations Europe probably first should look into installing large solar plants in Spain, Italy and Greece. Not only would it support the economies of those countries, but it would be very easy to connect those solar farms to the European grid. Also it would give a nice daytime distribution of the power as Spain and Greece are at the western and eastern borders of the European Union.

A distributed system of solar arrays intelligently placed on top of every building in the world, back-feeding into the grid or powering on-site batteries (Tesla Powerwall, etc.).

Or massive array in one geographical region susceptible to natural disasters, politics, or terrorism.

I'll take the distributed system.

There are benefits to both.

You can't use a distributed system for, say, Aluminum smelting, which requires tons of electric power.

If the idea suggested in the article is implemented, the Sahara could be turned into a "powerhouse" and an invaluable economic resource to the rest of the world. Integration of this system into the global economy would entail tremendous changes to both the world's interest and understanding of Northern Africa.

Solar panels on the sort of scale being discussed here would, once you consider the logistics of maintenance, basically be a small (or large) town that also has a huge number of solar panels.

Running a company town devoted to solar panel maintenance in the middle of the Sshara wouldn't be impossible, but it's a lot harder than just plunking down a one-time infrastructure investment.

Lets face it, if oil was discovered there, the infrastructure to drill and process it would appear. Is processing solar energy any more difficult?

>> "I think the only reason to pursue [solar panels in the Sahara] would be if it were a stopgap measure in which the long-term goal would be to reduce consumption of energy and to change our lifestyles to be more sustainable, so that subsequent generations don't have to deal with as many problems as we're going to leave them."

I hear this logic a lot and disagree. Finding more sensible and environmental ways to produce electricity needs to be the goal because we cannot be more sustainable. Mankind thrives on energy. I think the past 263 years (since Franklin's kite experiment) have shown us electricity is a way of progressing. We need power to run things. Where that power comes from is the difficult part. Unless another form of energy is found that can be used to work everyday devices from phones, to computers, to lights, not sure how we get away from electricity and only continuing to increase its consumption.

As for paneling the desert - The massive solar arrays in the Mojave desert outside of Vegas show that the sun can be used effectively, but the cost to produce the materials and impact on desert flora/fauna that go into the arrays are just as bad for the environment. The material cost alone in terms of environmental impact make it a laughable endeavor in terms of "environmental" concern.

I don't like her analogy in which she compares solar panels to smokestacks. As she points out, smokestacks were not a complete solution to air pollution because they merely moved the problem somewhere else. Solar panels are in no way comparable in that respect. The analogy only works if you consider energy production to be itself a problem.

"The analogy only works if you consider energy production to be itself a problem."

Welcome to environmentalism.

She could simply be trying to say that nothing is ever free. Conservation of energy dictates you need energy to produce energy, no matter the tricks you use to get energy there is always a cost even if it is not immediately apparent.

I think this line of reasoning just confuses the argument being made. The law of conservation of energy and the idiom that "nothing is free" are not the same. I believe the argument being made was that resource extraction and manufacturing for the machinery required for generating renewable energy causes as much damage to the environment as using non-renewable sources of energy. Im not sure if that is true, but I don't have the research to support either way. I do think that with more adoption and development of renewable energy, the extraction processes themselves could be made more environment-friendly.

If by conservation of energy you're referring to the first law of thermodynamics, then it's completely inappropriate to invoke as an argument for "no energy is free".

The energy in solar power is coming from the Sun. While there are various costs in capturing the radiation, converting it into some other form (like electricity) and shipping it around the globe, those costs have nothing to do with the first law of thermodynamics.

Yeah, people always seem to forget that most deserts have life. Then there's the clans of nomads that live in the Sahara. The need for, at least initially, military protection and patrols. Someone has to keep the power lines/pipes from being destroyed. And, of course, the countries surrounding the area aren't the most stable either.

The systems needed to control the automated surveillance drones coordinating the security teams would be interesting though.

A green energy solution would be nice but I have a hard time seeing covering Sahara in solar panels being it. To many variables, to big a project. Besides everybody want local solutions for national security reasons anyways.

>> "I think the past 263 years (since Franklin's kite experiment) have shown us electricity is a way of progressing

It would be more fair to give this honor to Faraday since he invented the electrical motor and other uses for electricity while Franklin proved lightning is electricity and invented the lightning rod. Having your house not burn down is beneficial to progress, in that you can spend less time building houses, but doesn't really fuel progress in itself.

I've always felt that Franklin steals the thunder by having a better, more dramatic story - the kite and all that. A genius in his own right though.

We don't need to cover the whole desert. The Sahara desert is HUGE: almost the size of China itself. We would probably use only a small fraction of the desert for energy production, and (hopefully) use the regions which affect the environment least.

As for security, I think its a tough question but not without solutions. Instead of treating the nomads as enemies, maybe we could explain to them the purposes of the project and reach some kind of understanding. This is a problem for diplomacy: not something that interest most HN readers.

As for Faraday not being recognized: there are tons of scientists who've made important contributions that are required for everything that we take for granted today. Franklin is probably more famous for being an astute statesman rather than as a scientist.

What about water usage? At scale, doesn't it take a significant amount of water (for a desert) to clean the dust off the panels?

Brushes are fine.

So the technology is already there, but we can't/won't implement this because of politics? What a shame!

When there's enough money to be made in it, private industry will just make it happen. We're not quite there yet, but it seems likely to happen as prices for solar keep falling. Politics don't have to enter into it, but government involvement has the potential to speed up the process.

What to do with the resulting electric energy?

(1) Smelt iron or aluminum?

(2) Split H2O into O2 and H2 and use the H2 for fuel.

(3) Convert water and coal to gasoline.

(4) Desalinate and/or purify water and use the water for humans food and drink, bathing, washing, swimming, lawns, greenhouse agriculture, or just to make the desert bloom?

(5) Heat salt to store the energy, and then run water through tubes in the hot salt to generate high pressure steam to drive steam turbines and, then, electric generators and, then, transmit the power across the Mediterranean to Europe and sell it?

Uses (1)-(4) have the advantages that get just to use the power while the sun is shining and don't have to store the power for nighttime use or transmit the electric power long distances. Would have to transmit the hydrogen or gasoline for those options.

In the words of the skeptical mayor's wife in the movie The Music Man, "I'm reticent. Yes, I'm reticent."

Why? The idea is not nearly new. So, I do have to suspect that a good engineering-economic analysis would show that we would need progress in:

(1) Keeping desert sand off the solar panels.

(2) In case want to use the electric energy to make hydrocarbons, a good source of coal near the desert.

(3) Energy storage.

(4) Superconductivity for the transmission lines across the Mediterranean.

Might be able to pay for it if the world can agree on some huge carbon taxes.

Nukes might be be cheaper.

Might keep in mind that the spot, wholesale cost of electric power in the US has been under $0.01 per KWH and the full cost, say, ballpark $0.06. So, the cost to a consumer of 10, 12, 22 or so cents per KWH is mostly for distribution, not generation. But the panels in the desert handle only the generation part, do nothing for the short distance distribution costs where the consumers are and make the long distance distribution, e.g., across the Mediterranean, more expensive.

Also on the money side, might want to keep in mind that the major oil sources in the Mideast pump oil for less than $1 per barrel. That price is tough to compete with.

Right, might be shipping the power to France which is doing quite well with nukes.

Then once carbon taxes start to take hold, people might watch

'The Great Global Warming Swindle'



and discover the evidence that CO2, methane, etc. from human activities has nothing at all to do with the climate or temperature of earth and, instead, changes in those two are driven by changes in the activity level of the sun, the sun spots, the solar wind, the blocking of cosmic rays hitting the atmosphere, the rate of formation of water droplets, the rate of H2O cloud formation, and, thus, the cooling effect of clouds.

Then people will object to carbon taxes.

Net, it appears that while the Watts of solar energy per 1000 square miles of desert are astoundingly high, for what people in the population centers want in electric power, motor fuel, clean water, etc., that desert solar power is just not very valuable.

The Media always seem to frame questions like this wrong. The question to ask is, "Why shouldn't we solar panel the Sahara Desert?" And once that question is answered we get started.

Well, the industry asked the question and then left the DESERTEC consortium.

who's going to dust the sand off the panels, with what energy though?

Sounds like a do-able job for robots, perhaps evolved from windshield wipers.

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