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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.
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=
Long distance power transmission is almost always DC for a number of reasons The first of these is are in DC there are no induction losses. The alternating current along transmission lines will inductively couple to each other and provide a loss in a similar manner to the crosstalk you get in everything from digital circuits to audio cables. DC just doesn't lose power this way.
AC is great for easy step up and step down in voltage, but it has a number of problems. In a transmission system you have two main limits, the maximum voltage you can use (limited by insulators used) and the I^2R losses in the cabling. Let's first assume no resistive losses or at least that you're not limited by heat loss: For a given cable and insulators you can therefore either run e.g. 1000V DC or 1000V AC Remember though that the AC is 1000V peak so the actual RMS voltage is effectively 1/sqrt(2) so 707V. Therefore for a given cable and insulator pair AC can carry less power.
The only way to reduce the I^2R losses is to run at higher voltages where currents required are less so DC will always be superior here provided your inverter technology is sufficiently efficient. Which for lengths of more than about 20km starts to happen.
What was true for the electrical systems of 20 years ago never mind back in the days of Edison is no longer the case, the AC vs DC situation is not as simple as it used to be.
"The weirdest thing about a mind, is that every answer that you find, is the basis of a brand new cliche" -