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mojavecasolararray.jpg

This solar grid in the Mohave desert utilizes thousands of mirrors called heliostats to focus solar energy on a boiler, where water is vaporized at over 1,000 degrees to create steam to drive turbines. Think of it as a nuclear power plant, without the radioactive dangers or the giant cooling towers to clog up the skyline. Overall this system can produce 240,000 megawatts of renewable electricity a year. Pretty cool idea and it looks rather intimidating from the air.

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Comments

  1. sam says:

    megawatts per year!!!
    sob

  2. Anonymous says:

    Don’t you mean megawatt hours!

  3. Anonymous says:

    “Malian Warlords and Confederate Ironclads not included”

    ^^ This was a joke about the recent movie Sahara, which featured one of these solar plants destroying toxic waste in the middle of the Mali desert.

    Sorry for the mistake, I can understand why Nigeria would be a little tense right now. That was a geographical error on my part.

  4. marty mcfly says:

    dr. brown would be proud — if i remember my prefixes, this would be 240 gigawatts…that means we could go back to the future at least 20 times!

  5. Reboot says:

    240.000 MW/y = 240.000 MW/235d = 240.000 MW/8760h

    So 240.000MW/y = 27’4 MW/h

    That’s way too low power compared with the 1,000+ MW/h from a nuclear power plant.

  6. Reboot says:

    Sorry, I wrote 235 days but calculated correctly with 365 days per year.

  7. Anonymous says:

    @marty:

    I think you’d have a hard time fitting one of these in a DeLorean.

  8. ssam says:

    @reboot

    no

    watt is a unit of power. 1 watt is one joule per second.

    joule is a unit of energy. it takes a certain amount of energy to a specific task, eg lift a weight to a height, make a cup of tea, light a bulb for an hour. you can get a certain amount of energy from eating a mars bar, draining a whole battery, burning a kg of coal, or running a power station for an hour.

    power is hour much energy you use/make in a given time. you use a certain amount of power to do a task continuously. it takes a certain amount of power to lift a weight up to a hight every second, to pump water up hill, to run a light bulb. a power station has a certain power output.

    so a megawatt power station, outputs a metawatt, or a megajoule per second. not a megawatt per hour or megawatt per year.

    it is equivalent to saying a train goes at 100 mph per year.

    its unfortunately a very common mistake

  9. Brendan West says:

    Now I know where the director of “Sahara” got the giant solar array to use for the movie! Betcha they filmed in the Mojave.

  10. Anonymous says:

    @Brendan

    The I think they might have filmed the mirrors at Mojave, but the set for the solar array was just that. It was significantly different than the real one. They only filmed the sequences where the actors are riding in a car down the road between the mirrors. The rest was miniatures.

    I still believe wind power is more efficient, especially in the desert. It’s estimated that more than a third of West Texas’ power needs are met by wind generators.

  11. FlatTop says:

    This kind of plant isn’t at all comparable to a nuclear power plant. From BrightSource’s web site:

    “DPT (Distributed Power Tower) heliostats are organized into a solar field, known as a Solar Power Cluster (SPC), which consists of thousands of heliostats sharing a common power tower. Each SPC produces 20 MW using Bright Source Energy’s current DPT 550 technology. A typical Bright Source solar power plant will consist of five (5) Solar Power Clusters and produce 100 MW of clean, cost-efficient electricity for supply to utilities.”

    So each tower produces 20 MW of power, but only when sun is shining. A single nuclear reactor can produce 700-900 MW all day and night, 365 days a year. Nuclear is a baseline power source while solar towers are a peaking source at best.

    A better comparison would be to a 40 MW gas turbine plant, where the solar wins on emissions but loses (badly) on portability.

  12. dustbuster says:

    The actual annual energy output from this plant seems a bit hard to pin down. Most online sources seem to use the figure of 10MW, which is probably peak output, much like the wattage figures on solar panels. So assume 8 hours of solar energy at say 60% of peak output (they use molten salt for thermal mass, so they don’t loose everything when the sun goes down). Over a year, thats about 17.5 GWhr of power. Or enough for about 950,000 homes at the San Francisco average domestic electricity consumption (18.5 kWhr/day/customer). Since most claims are at the 350-370,000 homes range for this unit, I’m going to assume that either I’m being too generous with my efficiencies, or SF customers are more frugal than the rest of the CA. In either case, very cool technology.

    As for comparisons to nuclear energy – no fuel, no containment, no disposal, no security risk, comparable maintenance costs, scalabililty (to some extent, thats what they’ve been doing, adding mirrors to increase capacity).

    I haven’t done life cycle costs on these things, but its a step in the right direction.

  13. BigD145 says:

    There’s tons of space in the desert and this sort of thing doesn’t hurt any endangered species. Nuclear has that SMALL problem of waste disposal. This includes 15 years of above ground and on site storage along with the billions of years of long term storage. Let’s not even go into how fatal the stuff is or the fact that it is a limited resource, like coal and oil. Or maybe we should go into all that.

  14. vivi says:

    @FlatTop : The energy come from the Sun, which is a giant fusion reactor, so this sense it can be compared to a (thermo)nuclear reactor.

    To add my grain of salt to the unit debate, the article states that the energy output of one plant is 246,000 megawatt hours per year (which makes sense unit-wise), which is equivalent to an average of 28MW. For comparison the biggest wind turbines (200m high) can produce up to 6MW.

  15. JennaSys says:

    I believe the reference to a nuclear plant in the article was intended not as a power output reference, but as an operational reference in that the energy source is used to create steam to power a turbine which turns a generator.

    I don’t get why so many people insist on assuming that we need to use only 1 source of power. This argument over “wind is better than solar is better than biofuel is better than nuclear is better than whatever” is ridiculous. They all have their pros and cons. What is best depends on the logistics of the location, availability of resources, and the demands of the area. But even then there is no reason to necessarily utilize only 1 source of power. We don’t use 1 source of energy now (coal, nuclear, oil, hydro, natural gas, propane, etc.) why would we need to rely on only 1 source of emerging cleaner energy? As someone just mentioned, the Mojave desert is a big place and can support many of these types of solar installations, as well as PV solar farms and wind farms too. Diversification and redundancy is GOOD!

  16. zof says:

    I would like to point out Mohave is Arizona desert, Mojave is a California desert, don’t ask me why I think different tribes of Indians. Common mistake except when you live close enough to hear every time Scaled Composites blows something up in the Mojave desert.

    Sorry for being anal.

  17. JennaSys says:

    I wasn’t positive myself, but after doing a few quick searches, it seems that while Mojave and Mohave can be acceptable when referring to the Native American tribes that the desert region was named for, when referring to the desert itself, it is spelled Mojave regardless of which side of the Colorado river it’s on. Then again, I’m also in SoCal so I’m used to seeing it written as Mojave. Could it be Mohave county, AZ that you are thinking of (which I believe makes up part of the Mojave desert)? Uh oh, I think my OCD is showing…

  18. Anonymous says:

    “Uh oh, I think my OCD is showing…”

    It is CDO, if you alphabetize it correctly… :-)

    Yes the county is desert area.

  19. JennaSys says:

    “It is CDO, if you alphabetize it correctly…”

    So THAT’S what the -Disorder- part refers to!

  20. My Pet Fly says:

    I’ve driven by this several times before — it’s known as Solar One. The heliostats collect so much sunlight together that you can actually see the air glowing where the beams intersect. The artist’s conceptions on the site do a reasonable job of showing it, although it’s more spectacular in real life.

  21. Anonymous says:

    If you figure the average home consumes 20kwatts/day, or 7.3megawatts/year, then just one of these can power about 32,000 homes? If there are 300 million people in america (average 4 person family), we would need about 2,300 of these solar plants to be completely off the grid (not including businesses). Not sure if there’s that much land in the desert.

  22. Trent says:

    “we would need about 2,300 of these solar plants to be completely off the grid (not including businesses). Not sure if there’s that much land in the desert.”

    The Mojave is 14,000,000 acres. Divide it into 5000 sections and each section is 2800 acres. The land in the photo covers much less than 100 acres. The Mojave has 25+ time as much space as would be needed. And that is just the Mojave…

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