An Aussie Visiting America - Boulder City Solar

During a trip in August, across the United States, one of the things I had planned was to visit a number of solar installations. Just out from Las Vegas, not far from the airport at Boulder City which flies people to/from The Grand Canyon, there is a substantial solar trough power station. Its output is 65 Megawatts, which using rule of thumb of 1,000 people per MW, can supply enough power for 65,000 homes whilst the sun is shining.

For a city heavily dependent on the Hoover Dam for its power and water, any means to potentially reduce water flow for power generation out of Lake Mead, makes sense. Particularly when you consider the drought and massive drop in water level in the lake since 1999.

It is estimated that by 2012, the lake’s surface could fall below the existing pipe that delivers 40 percent of Las Vegas’s water.

Although the Acciona plant was commissioned in 2007, the United States has had an operational solar thermal trough power station for well over 20 years at a place called Kramer Junction.
Description of Power Plants

  • 5 fields of 33 MW each
  • Operational and commercially viable since 1985
  • Excellent reliability
  • Displaces over one million barrels of oil
  • 15 additional years working life expected
  • ...fast-tracking the concept to the point where it was a viable, job-creating, clean source of electricity. Kramer Junction power station employs 125 people - managers, operators, maintenance staff... and mirror cleaners....

    Page 51 The Big Switch, Clean energy for the 21st century, (c) 1994, Gavin Gilchrist

    In Luz's design, the solar trough heats a working fluid that circulates to a power station where water is super heated into steam, which then powers an electricity producing turbine....

    The power plant built at Harper Lake, California, in the Mojave desert in 1989
    ....produce enough power for about 170,000 homes for as little as 9ckWh

    Page 145/146 Power Surge (c)1995 Christopher Flavin, Nicholas Lenssen

    This diary is a bit of a follow on from a couple of others I have written and there are more to come.

    An Aussie Visiting America - Las Vegas

    Oz Solar Technologies

    I'd scheduled a trip to the Grand Canyon leaving out of Las Vegas early in the morning and returning back to the Boulder City airport around lunch time. This I had hoped, would give me enough time to hail a cab and drive out to where the Solar power station was. For those that don't know how this Rankine type of power station works, below is a graphic of the heating and cooling cycle of steam from Wikipedia.

    Rankine cycle

    When water is heated to steam it expands over 1600 times its volume. In the instance of a power station, by keeping the steam contained the pressure of the steam increases. By then allowing this high pressure steam to flow to a lower pressure environment, as it passes through the blades on a turbine, like a great big fan with many blades, it turns.

    In the graphic above you can see at 1, cold water from a condensor via a water pump, entering a heating chamber at 2. As the water heats above 100ºC it changes state from a liquid to gas, so its volume expands. Because it is contained this volume of gas becomes compressed and at 3 the pressure of the steam is high enough to drive a mechanical turbine. The turbine is attached to an alternator or machine which produces electricity.
    The steam re-enters the condensor at 4, where because it passes through cooling water tubes Q out, condenses the steam which had been expanded over 1600 times, back to a liquid.

    Note at this point also, the condensor operates under a vacuum because of this collapsing gas.

    Usually the heat is provided in modern power stations by a combustible, most often coal or gas or other fossil fuel. However in a solar thermal trough station, the heat is provided by the sun with the other basic theory of operation remaining the same.

    Nevada Solar One

    Nevada Solar One uses 760 parabolic troughs (using more than 180,000 mirrors) made by Flabeg AG in Germany that concentrate the sun's rays onto thermos tubes placed at the focal axis of the troughs and containing a heat transfer fluid (solar receivers).

    These specially coated tubes, made of glass and steel, were designed and produced by Solel Solar Systems as well as by Schott Glass in Germany. Motion control was supplied by Parker Hannifin, from components by Ansco Machine Company. The plant uses 18,240 of these four-meter-long tubes. The heat transfer fluid is heated to 735 °F (391 °C). The heat is then exchanged to water to produce steam which drives a conventional turbine.

    Below in my first two shots are an aerial photo where you can only just make out the shimmer of the plant from the air. The purpose of this shot was to demonstrate just how much suitable land there appears to be in this area. The second is a shot of the plant from the road. I'd talked my way into someone from the airport driving me down to look at the plant which I'd estimated was about 10 minute drive. Turned out it was closer to 20 minutes one way.

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    These shots are not very good as I was on the other side of a chain link fence. However in the close up you can see what appear to be heat transfer medium tanks or maybe water for mirror washing, and in the smaller close up you can just make out the troughs themselves.

    PhotobucketPhotobucket
    Photobucket

    Because I was disappointed in the photos I was able to take, below are shown the parabolic troughs, heating fluid lines, and a means for washing the mirrors.

    PhotobucketPhotobucketPhotobucket

    Link to Google Map

    Aerial Photograph from Treehugger

    Video of the plant from others.

    One would think I'd have been disappointed driving all the way down to this plant and not being able to get much more than outside the gate, but not really. Because there were a few things I took from this. The first is this power station is located right near a massive high voltage distribution switchyard.

    Obviously one which distributes power from the Hoover Dam to Las Vegas and beyond. Secondly there is a massive amount of land in the valley which would be subject to the same solar insolation numbers as Nevada Solar One. Third Vegas could get behind a project like this which would put its construction workers, who at the moment have no work, back into a job - its only about a 1/2 hour drive.

    But Fourth and the most important is there are already 86 projects on the books for Southern California which mean 200 times this sized plant.

    That's right if built the same that is -

  • 200 x the 180,000 mirrors
  • 200 x 760 parabolic troughs
  • 200 x the construction jobs
  • 200 x the manufacturing of turbines, mirrors, framework, steel jobs
  • 200 x the maintenance jobs for operators, mirror cleaners, engineers and managers.
  • Below I've given a short tally of some of the solar projects slated for Southern California. Taken from this list for South East California on the Solar Energy Industry Association website.

    Developer Project Name Electricity Purchaser Location Technology Capacity
    Abengoa Solar Mojave Solar PG & E San Bernandino County Trough 250MW
    Abengoa Solar Solana Arizona Public Service Gila Bend Az Trough 280MW
    Acciona Solar Power Ft Irwin Solar Power US Army Ft Irwin CA Trough 500MW
    Brightsource Energy Ivanpah Solar Electric Generating Southern Cal Edison Nevada Tower 1200MW
    eSolar Gaskell Suntower Ph I&II Southern California Edison Kern County Tower 245MW
    Harper Lake LLC Harper Lake Solar plant California Trough 250MW
    Solar Millenium Amargosa Farm Road NV Energy Nye County Trough 484MW
    Solel Mojave Solar Park PG & E Mojave Desert Trough 553MW
    Tessera Solar SES Solar One Southern Ca Edison Victorville Dish-Engine 850MW
    Total projects 86 Total Megawatts 13,570MW

    So there are a LOT of solar power plants going through the engineering and approvals process for Souther California. In fact so many I'd suggest that they would go a long way to meeting a significant part of California's electricity demand of around 33,000 Megawatts. At least during the day.

    Not to mention the jobs. Seeing things like this happening in the United States gives me hope that you are going to help lead the world to a cleaner and greener energy future, and start giving back some hope to young people again that there will be work, there will be a future by moving in this direction.

    Continued tomorrow....

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