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Salt-based solar thermal plant takes shape in Nevada

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CleanTechnica

The notorious Crescent Dunes Solar Energy Plant near Tonopah, Nevada passed another milestone this month, as workers finished placing receiver panels on top of a 540-foot tower that forms the centerpiece of the facility. Crescent Dunes is based on molten salt thermal technology and we say notorious because when completed, Crescent Dunes will give the U.S. bragging rights to the largest renewable energy plant of its kind in the world. In certain quarters, however, the project is also notorious because it benefited from a federally backed construction loan to the tune of a whopping $737 million, creating another potentially juicy opportunity for critics of the Obama Administration’s renewable energy policies.

Unfortunately for anyone who is still rooting for failure, Crescent Dunes is on track for completion by the end of this year.

Crescent Dunes Molten Salt Solar Thermal Power Plant

What makes Crescent Dunes unique among commercial-scale solar power plants is its integrated energy storage system. According to developer SolarReserve, the facility can provide up to 10 hours of full power storage, which enables it to supply power on an on-demand basis, just like any fossil fuel or nuclear power plant.

Crescent Dunes is similar to a conventional concentrating solar power (CSP) system, using thousands of special mirrors called heliostats to focus solar energy on a central tower.

The difference is the use of molten salt, which flows through receiver panels at the top of the tower, consisting of alloy tubes. The salt retains solar energy in the form of heat, ranging in temperature from 500 degrees Fahrenheit to more than 1,000 degrees. That enables salt to double as both an energy transfer and an energy storage mechanism.

Unlike water, molten salt remains in a liquid state at these high temperatures, enabling it to be transported to ground level and stored through a relatively inexpensive system of pipes and tanks. On an as-needed basis, the heated salt is used to boil water to operate a steam-driven turbine, a part of the process that is exactly like any conventional fossil fuel power plant.

Crescent Dunes And Green Jobs

The recent spate of news about China’s horrific smog-induced public health crisis is a reminder that here in the U.S., we’ve managed to decouple economic growth from the worst effects of fossil fuel dependency. However, the public health costs of fossil fuel dependency still linger, and there is plenty of wiggle room to create a firm platform for sustainable economic growth while reducing pollution even further.

That’s where clean, renewable energy projects like Crescent Dunes come in. Despite the blowback from other conservative legislators, Republican representatives from Nevada went to bat for Crescent Dunes as a win-win economic engine for their state.

The project also gives Nevada bragging rights to cutting edge solar thermal technology designed by SolarReserve’s technology partners including rocket science pioneer Pratt & Whitney Rocketdyne. That could make a big difference to Nevada, which finds itself lagging behind as Arizona governor Jan Brewer has apparently shelved climate change denial in favor of an aggressive push to woo more clean tech startups to her state.

Currently, there are about 450 workers at the construction site, with a total of about 600 on site jobs expected for the overall length of the 30-month construction period. The on site jobs add to a total of 4,300 direct, indirect and induced jobs expected during construction.

One operational, the 110 megawatt facility will provide enough power for up to 75,000 homes at peak periods and pump $10 million annually into the economy in the form of salaries and other operating costs.

Crescent Dunes And The Keystone XL Pipeline

All of this is by way of a reminder that it is possible to promote economic growth and employment opportunities while adding significant capacity to the power grid, without exposing communities to the risks and impacts of fossil fuel harvesting and transportation.

While fossil fuel projects like the proposed Keystone XL tar sands oil pipeline have been touted as the best way to create new jobs, the latest argument against it just occurred last Friday in Arkansas when an existing Exxon tar sands oil pipeline ruptured, spilling oil into a residential area and threatening a nearby lake.

Meanwhile, Arkansas and other midwestern states, which used to be considered seismically quiet, have seen a massive spike in earthquakes lately, and seismologists are beginning to amass evidence that the phenomenon is related to the practice of injecting oil and gas drilling wastewater into abandoned wells.

The combination of human-induced earthquakes and underground pipelines adds a new element of risk to ventures like Keystone. Stay tuned.  

Pocket
  • colin

    Duty cycle of 55% isn’t all that terrific

  • James Fisher

    55% is plenty as it is delivering power when it is needed. There is very little demand after 10pm and before 6am.

    Typically coal plants run at 100% capacity 24 hours a day. This is a huge problem for them in the current environment as they lose money in the off peak periods when their costs exceed the price they can sell their power. Normally the profit made in the peak periods would more than offset the losses in the off peak periods, but PV and wind are removing the peak periods and making the coal plants unprofitable.

    The ability of solar thermal to deliver power into the most valuable periods makes its average revenue per MWh substantially higher than coal, wind and PV.

  • Luis Cuevas

    Next time you need a picture taken and edited by me, I’ll appreciate you quote me as author of it. http://www.sxc.hu/browse.phtml?f=view&id=1408596