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Sahara Solar To Power Half the World By 2050
eldavojohn writes "A Japanese/Algerian effort called The Sahara Solar Breeder Project employs a simple concept revolving around the pure silica in the sand of the Sahara Desert. The silica can be used to build vast solar arrays which will then provide the power and means to build more solar arrays in a classic breeder model. They would then use DC powerlines utilizing high temperature superconductors. The lead of the project points out that silica is the second most abundant resource in the Earth's crust. The project's lofty goals to harness the Sahara's energy has a few requirements — including 100 million yen annually — but also the worldwide cooperation of many nations and the training of the scientists and engineers to create and man these desert plants. The once deadly wasteland of the Sahara now looks like a land rich in an important resource: sunlight."
Now all we have to do is build a massive worldwide network of new transmission lines, stabilize the governments of Africa, and get every country in the world to agree on how the power is to be shared.
SJW: Someone who has run out of real oppression, and has to fake it.
100million yen is 1 million dollars...That really isn't much money.
That said, the project is incredibly unrealistic, or at least the stated goal is.
Professor Koinuma is on the right track here. The Sun, being the most abundant source of renewable energy, is obviously the most efficient resource to power the world.
We could power the world using only a fraction of the Earth's surface area.
I really hope that this project succeeds, even if it is done on a smaller scale.
He who knows best knows how little he knows. - Thomas Jefferson
The thing is, it doesn't cost much to try. And if this thing works, it could be a huge boon for the world. We definitely need to ramp up production on solar to get extra energy. Surplus energy could be used for electric cars of the future. Electric cars could then transport goods cheaper than they do now, allowing for people with low income to afford transportation & food.
God spoke to me.
So, how long will this dream last after the first lawsuit to protect some insect local to the area to be covered by solar panels?
Yes, it's not the USA, but the companies involved in the process will be first world companies, with all the potential for idiotic lawsuits implicit in first world sensibilities....
"I do not agree with what you say, but I will defend to the death your right to say it"
AC is more stable over distance because DC has to compete against natural differences in ground voltage, but DC is better for really long distances as it is theoretically nearly lossless while AC loses proportional to the length of the cable.
Why DC when AC is better for long distances?
It's not - high voltage is better for long distances than low voltage, but it doesn't matter if it's AC or DC.
AC is better because it can be run through a transformer and stepped up or down to different voltages for long distance or local distribution - it's the high voltage that's better for long distances because Power = Volts x Current, and wires carry voltage more easily than they carry current. The efficiency of the transmission line has nothing to do with wether the voltage is AC or DC, but everything to do with how high the voltage is.
High voltage DC could be used, but before the advent of inverter technology there was no easy way to step a DC voltage up or down, so power generating utilities almost universally use AC.
Using an ideal superconductor instead of normal metal wires would eliminate the resistive losses in the transmission line, but it sure sounds expensive.
DC is used at some points in the power grid, presumably at interconnect sites where power from two or more generating facilities has to be combined and the AC voltages are out of phase or not at the same frequency.
I honestly think the inclusion of superconductors is just to make the project more buzzworthy. There's no advantage to using high voltage DC especially when they're intending to run PV production plants off of it - A/C is much more useful in that case.
At least Saharan Africa is more stable than sub-Saharan Africa politically. Haven't been there since the late 1970s, but it was a fun vacation.
Putting moderation advice in your
Distributing energy from the Sahara to all the world will meet some resistance.
Sandstorm + Solar Array = ???
AC is actually NOT better for long (and I mean LONG) distances. Short to medium runs (dozens of miles) it's not too bad and the ability to efficiently change voltages with AC using transformers means you can keep current down and wire sizes small.
AC won out in the beginning because there was no cost effective means to alter DC voltage between efficient transmission voltage and safe/practical usage voltage.
However, wires have capacitance. Overcoming that capacitance requires energy, which is an inefficiency. When your cable goes from dozens of miles to hundreds of miles these losses become significant. DC doesn't have to deal with the capacitance issue, so it is actually more efficient here. Modern solid state power electronics also make changing DC voltages efficient and practical enough to use HVDC across long distances and Medium-Low Voltage AC for local distribution.
Add superconductors to the mix and the advantage of DC increases substantially.
Lastly, transmitting in DC solves problems with synchronizing and matching AC frequencies where otherwise independent grids interconnect. Each end of the DC link doesn't "see" or care about the frequency/timing of the other end.
=Smidge=
The Splice Must Flow!
AC and DC power lines both loose energy to resistance. AC power looses energy in another fashion due to capacitance and inductance called reactive power. By using superconductors (0 ohm resistance) for the power lines, you eliminate all losses for DC, most losses for AC, and introduce new losses for the cooling equipment. Of course, with superconductors the formula isn't as simple as V=IR because then you could get infinite current. (V/0 = I) With superconductors, there is a maximum current density (Amps per m^2 as the area of the cross section of the wire) before the wire starts to produce resistance.
"For every complex problem, there is a solution that is simple, neat, and wrong." - H.L. Mencken
DC loses power through the ohms law
AC can lose power thanks to being a nice antenna. If your transmission line becomes a nice multiple of the wave number, then you are fucked. Manitoba Hydro has the largest DC transmission lines in the world for long haul lines. When they started with AC, they suspected a slightly more loss until they powered them up. Turns out 1250km is a nice 1/4 wave number of 60Hz. So, they ended up with majority losses on the line. This is why long distance AC lines are a failure.
Secondly, solar panels are inherently DC. DC-DC tech is matured over last 100 years. And DC is easier to invert to various AC standards around the world than another AC.
I think we should switch to complete DC transmission, but then there is a shit-ton of legacy gear.
Actually the superconductors are not even needed. For high voltage long distance power transmission HVDC is very effective, relatively cheaper than AC, and quite common these days.
See the 500 KV Pacific DC Intertie between the Columbia River and Southern California. A friend of my family's was one of the engineers on that, the first such high voltage DC line built in the US. The technology mostly existed as far back as the 30s, and according to this article several such systems were built in Europe in the 1950s. But HVDC really became most practical with the advent of large, fast stacked thyristors and other solid state controls (as discussed in Wikipedia).
According to my friend, at these high voltages most of the power is transmitted in the field surrounding the wire, not the wire itself. However according to the above article, the key is the high voltage, which keeps resistance losses low - about 3% per 1000 km. Also underwater cables are often DC because an AC cable underwater would look like a very long capacitor, coupling to the conductive water outside the cable and losing large amounts of power.
HVDC also has the advantage of eliminating the issue of synchronizing the AC signal across very long distances and between two dissimilar power systems.
The HVDC article in particular goes into the pros and cons at great length.
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Disclaimer: I'm not a power engineer but I am an electrical engineer, so while the principles I state are probably correct there is some guesswork as I apply it to power transmission.
However, wires have capacitance.
Yes, all wires have a certain capacitance and inductance per length. Given the very wide separation between the power line and ground the capacitance per length should be very small, since it is inversely proportional per distance. Given the wide area the current encloses, the inductance will conversely be large. Therefore I would guess that the inductance of the transmission line is more important than its capacitance, and that it can be modeled primarily as a resistance in series with an inductance.
Overcoming that capacitance requires energy, which is an inefficiency.
Correct, though I'd like to add to that. An ideal capacitor is a lossless device (if you bring up the "two capacitor problem" note that by definition the capacitors or the wires connecting them cannot be lossless or it would never reach steady state). However in any AC transmission there will be conductor loss due to the resistance of the wire, possibly increased by skin effect, and dielectric loss due to the changing polarization of polar molecules in the dielectric surrounding the wire. Air is a virtually lossless dielectric. The wire's insulation is not going to be lossless, but since dielectric loss is usually proportional to frequency and 60Hz is very low frequency, and the insulator is small, I would guess that conductor loss dominates. And since frequency is very low skin effect may be negligible and we can just use the DC resistance.
One more note is that most loads are inductive (ballasts for flourescent lights, motors for air conditioners, motors for industrial equipment, transformers, etc) and this is probably going to dominate the power factor of power transmission much more than the reactance of the power transmission lines themselves. That's why most load compensation is in the form of added shunt capacitance.
Of course there are still many advantages of DC transmission, but for power lines on poles I wouldn't be convinced of frequency-dependent loss playing a large role unless I saw a full analysis.
Can't see the video at work, so maybe I'm missing something. But this really seems like pie-in-the-sky to me. A couple of things:
I'm not really sure why the organizers are determined to do this in the most difficult way possible. There's sand and sun all over the place, including many that are a lot closer to electrical markets (the US southwest, for example). So why not just build these things there and sidestep the whole issue of superconducting wires? This plan doesn't make sense to me.