Should we solar panel the Sahara desert?
bbc.com
bbc.com
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).
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.
plus you would have the added problem...
Those are fair points, I think much more significant than the transmission losses.
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.
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.
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.
http://mobile.abc.net.au/news/2015-11-12/renewable-hydrogen-...
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.
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?
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."
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.
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.
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.
Or massive array in one geographical region susceptible to natural disasters, politics, or terrorism.
I'll take the distributed system.
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.
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.
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.
Welcome to environmentalism.
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.
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.
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.
(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'
at
https://www.youtube.com/watch?v=52Mx0_8YEtg
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.