Gallery: Commercializing Solar Power with Molten Salt


Solar power might be the most up-and-coming renewable energy source, but one of the biggest drawbacks to solar power plants is their inability to generate electricity at night or during cloudy days. But now, a new venture called SolarReserve hopes to change all that using salt! Their program would save and store captured solar energy in molten salt, the new solar plant will produce up to 500 megawatts of peak power — comparable to what a regular coal power plant can produce, only with no greenhouse gas emissions.

Unlike other solar power plants, SolarReserve’s will be able to produce electricity at night or in inclement weather. You can see the commercial potential here if you note that just one megawatt is enough power roughly 1,000 U.S. households. The company hopes to build 10 plants over the next 10 to 15 years.

The concept behind new concentrated solar power plant is very similar to Seville’s solar power tower where hundreds of solar panels reflect the sun’s light to heat the water inside the tower, which later evaporates into steam that passes through series of turbines to generate electricity. However, instead of tower that holds water, SolarReserve’s holding tank will have molten salt. Huge array of mirrors will reflect light onto the tank; heated 1,000 degrees Fahrenheit liquid is then pumped into a steam generator that will turn a turbine to make electricity.

“Due to the unique ability of the product to store the energy it captures, this system will function like a conventional hydroelectric power plant, but with several advantages,” says Lee Bailey, managing director of US Renewables Group, SolarReserve parent company. “This product is more predictable than water reserves, the supply is free and inexhaustible, and the environmental impact is essentially zero.”

SolarReserve says that their use of molten salt, a mixture of sodium and potassium nitrate, instead of water or oil, allows the heat to be stored for use when sun is not present. The National Solar Thermal Test Facility conducted several studies and concluded that molten salt is the most efficient fluid when it comes to transporting sun’s heat. The study states, “molten salt is used in solar power tower systems because it is liquid at atmosphere pressure, it provides an efficient, low-cost medium in which to store thermal energy, its operating temperatures are compatible with today’s high-pressure and high-temperature steam turbines, and it is non-flammable and nontoxic.”

+ SolarReserve (US Renewables Group, parent company)


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  1. SkyFuel's SkyTrough the... September 3, 2010 at 4:03 pm

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  2. Shankargouda March 31, 2010 at 10:43 pm

    This appears to be ultimate at present

  3. JayCN July 25, 2008 at 12:03 am

    I am a student on the subject. I would like to learn more.

    Thank you.

  4. willco June 17, 2008 at 6:35 pm

    Rocketdyne has been working with various forms of liquid sodium for about 40 years. Some of the forms are so toxic that few vessels can contain them. Others are not.

    There is a lot of talk about the negative aspect of size of the solar installation but the illustration does not look all that massive to me.

    People in Phoenix do not use solar because they have abundant supplies of cheap hydro-power. People use gasoline in general because it has been a very cheap source of energy for quite some time. As that is changing new forms of power generation will become viable – we hope. Will

  5. solarfeeds June 6, 2008 at 11:13 pm

    very ineteresting article.
    looking for solar writes on solarfeeds dot com, if anyone is interested. TIA


  6. David Lee May 9, 2008 at 6:58 pm

    I just have noticed that Pratt & Whitney Rocketdyne, Inc. holds the US Patent #7299633 ( Solar dish concentrator with a molten salt receiver incorporating themal energy storage).
    It seems to me this is exactly the same technology which “SolarReserve” is building their system as described above.
    I am wondering how “SolarReserve” can build the solar system when someone holds the Patent. Do they pay for royalties? Maybe slightly different method do they apply?

  7. papito May 5, 2008 at 4:47 pm

    The oil companies will never permit this!!!They own most oil and gas reserves in the world and their lobby is awesome; what we need is a President who can stand up to them and give power back (literally) to us, the PEOPLE!!!Please respond, YES, WE CAN!!!

  8. Chris Reilly March 11, 2008 at 6:44 pm

    I was recently in Arizona and read (with great interest) the articles on the solar/electric power plants. I think its great that the investments are being made. But, I am a little confused or maybe concerned. We drove around the Phoenix area in the glorious sunshine for about a week, basically from one beautiful exclusive golf course to another, and saw only one roof top solar collector. I looked at hundreds of thousands of houses and buildings and only noticed one two-unit water heating roof top solar collector. What’s going on? I CAN’T BELIEVE THAT INTHE VALLEY OF THE SUN PEOPLE ARE USING GAS AND OIL AND ELECTRICITY TO HEAT THEIR HOMES AND WATER.

    Something is wrong! The technolgy has been around for more than twenty years and it’s just being ignored. Where small investments, far less than your BMW, with paybacks of seven to ten years could readily provide in excess of 50% of the energy used in the region. The people just sit on their hands and wait for someone to take care of them – the goverment – the utility – the oil producers – the automakers (where are the electric cars). Well the utility or at least a foriegn utility says OK we’ll do it. We will spend the billions of $$ and we will get our money back even though it may take thirty years. The same people that won’t put a collector on their roof (space that is already wasted) will pay more for those plants and its power.

    Meanwhile the growth for electric power parades along at 280MW/year in the valley of the sun. And almost everyday in the valley of the sun (I guess 335 days/yr, cause we get the other 30 in upstate NY) the power of the universe bestows in excess of 10,000 times the energy needed.


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  10. Mekhong Kurt March 4, 2008 at 8:37 pm

    I’m an American living in Thailand. Successive governments here have never been noted for being exactly forward-thinking.

    Yet within the past decade or so, a Skytrain and subway have been built, with extensions underway or planned — two systems that have visibly ease Bangkok’s notorious traffic congestion.

    And that’s despite the strong political influence of multinational oil companies, which have a very strong presence here.

    Further, under government prodding, more and more taxis are switching from ordinary gas to natural gas. It’s true that service stations having natural gas for refills aren’t as common as those offering ordinary gas and diesel, but they’re there, and their number is increasing, if slowly.

    I was surprised to read about the gone-by-the-wayside electric vehicle. Guess people making those observations haven’t heard about (to cite but one example) the explosion in sales of electrically-powered bicycles in China. (Yes, the batteries present a very large environmental challenge, but I’m not talking about that. I’m talking about the so-called “death” of electric vehicles.)

    Not all the current manisfestations of alternate power-generating technology will survive in the market place. But some will survive the shakedown cruise, then we’ll see a convergence towards whatever turns out to be the superior versions.

    It’s not a question of “if.” It’s a question of “when.” After all, we’re using up natural fuel reserves at a rate that’s not sustainable. Yes, experts parry over whether we’ll run out in X years or 1,000X years or sometime in between — but none submit we’ll *never* run out.

    No time like the present to start looking at ways to make the transition to other sources of energy.

  11. Stan February 1, 2008 at 1:17 am

    Reply to Frank:

    The molten salt is really salt peter, an inexpensive, eutectic mixture of 60 percent sodium nitrate and 40 percent potassium-nitrate. (
    Yep, plain old fertilizer. It is non-flammable and nontoxic and very importantly, cheap. There are other better heat transport choices but more expensive such as NaK. The molten salt has been tried in proven and used in industry safely worldwide. Go to Daggett, CA and see the Solar Two that operated as a research plant flawlessly for a year to prove the concept. A little research and due diligence goes a long way before posting your misinformation.

  12. Phil Pense January 29, 2008 at 12:54 pm

    Fascination technology, What is the efficient temperature range of molten salt?

  13. Phil Pense January 29, 2008 at 12:52 pm

    Fascinating technolgy. I write to inquire about the temperature ranges for the efficient uses of molten salt. Much thanks for your attention as I await your reply.

    Phil Pense

  14. Dave January 29, 2008 at 8:54 am

    This is impressive, i could see ir working for African countries where there is huge unused spaces and deserts

  15. Deep Patel January 22, 2008 at 6:40 pm

    CSP (Concentrated Solar Power) is on the rise. Its acutally the fastest growing segment in solar. CSP can provide lower costs per watt than traditional solar PV applications. Most of these plants are put up by utility companies or private investors who are looking to build and flip the facilities off to a utility in the future.

    The spanish have control of this market, most of the CSP companines come from spain and have the expertise in developing parabolic troughs.

    Sometimes CSP plants also have a backup natural gas tank, just incase they run low on heat to turn the turbine at night.

    -Deep Patel

  16. bret carr January 20, 2008 at 1:56 am

    Beautiful aesthetics. The momentum wont stop – this is simply evolution in consciousness and it will be followed as people become vegetarians and humanists. Meaning they will renew the earth and animal life and human life.

  17. Andrea January 17, 2008 at 3:15 pm

    In response to Adam comment to Greg, you are discussing the same issue that he brought up. The main issue is conservation and increased efficiency before alternative energy (including turning down the heat). The more people try to conserve, reduce, reuse, & recycle the better off we will be.

  18. Mark January 17, 2008 at 1:06 pm

    It will probably disappear like the electric car. As long as there is oil, the gov’t and big oil will make things that are efficient, affordable be no more. Big oil cannot make the profit and the feds cannot collect the massive taxes. Oil companies will buy them out or the feds will pass some regulation making it unfeasable to continue.

  19. Energy-Guru January 15, 2008 at 9:17 pm

    This is exciting news. Solar energy has tremoundous potential, which is largely untapped. Imagine if we could harness this inexhaustible source of energy. With recent developments in technology, solar energy systems are scalable for large and small uses and require no maintenance.
    “Enable Global Adoption of Renewable Energy”

  20. ooooze January 15, 2008 at 8:46 pm
    check out the DOE solar 2 project that was running from 1995-1999. It used molten salt + heliostats too.
    Glad to hear it’s going commercial though.

  21. Andrew January 15, 2008 at 8:19 pm

    Anyone with a semester in chemistry should realise that sodium nitrate is not metallic sodium.

  22. Sean January 15, 2008 at 8:14 pm

    There sure seems to be quite a bit of negativity around here. This technology is currently in use in a plant in California. If you live out there you may have seen it on the 15 fwy in the desert. It is quite impressive just after sunset. You can actually see the tower glowing in the middle of the array.

  23. Frank is stupid January 15, 2008 at 8:02 pm

    That kind of “TERROR Talk” is why we are paying so much at the gas pumps…every one is so scared of some “exploding” new technologies, well take a look at your HIGHLY volatile fuel tank on your car of EXPLODING GAS!!!!!!!!!!!

  24. Adam January 15, 2008 at 6:38 pm

    I think its an awesome idea… But greg, I think you have a backwards way of looking at things. I understand the concept of living efficiently, but you say “turn down the heat”… What about just building, buying, or renting a house that has super insulation? And while electric cars are a wonderful idea, what about the people who 1) can’t afford one, or 2) live in places like ohio and have to commute further to work than one of their little batteries go. And last but not least, yes, yes, turn out the lights. But why not invest in LED light bulbs, and also get something like a green switch to avoid phantom drain from things like televisions, cable boxes, and dvd players?

  25. Frank January 15, 2008 at 11:45 am

    I hope everyone realizes that when they say liquid salt that they are dumbing down and trying to make metallic Sodium seem eco-friendly and viable. This company plans to use elemental sodium, as in pure Na, as the heat sink instead of water.

    As anyone with a semester of chemistry should realize, metallic sodium is a liquid at the boiling point of water, so that is behaves like water in that respect. But is also highly caustic and potentially explosive if allowed to react with water, or even air. And they are planning to use it as a heat sink?! More like a potential bomb.

    This is a reason that few conventional power plants use Sodium to run their turbines, in that they don’t want to risk them EXPLODING!

    I’m all for renewable energy but is liquid sodium, not this sanitized ‘molten salt’ line of BS , really a safe answer?

  26. Stacy January 15, 2008 at 7:28 am

    Molten salt, that’s a strange way to put it. You’d expect them to use anything but salt. It doesn’t sound very high-tech. Science nowadays. I wonder how long they have been doing this. It makes you think whether it’s a concept that really works.

  27. Al Pittis January 15, 2008 at 6:11 am

    Seems a very interesting technology – I’m all in favor of solar – but why is it being being constructed on a such a massive scale? We’re back into the business of needing massive powerline infrastructures to pump the power around the country. {With all its associated blackouts and grid mismanagement.}
    Is their some economy of scale that prevents this technology from being viable for small scale operations? To use an IT analogy – we seem to be building a mainframe: surely a smarter web of smaller stations would help us bypass many of our historical grid management issues.
    Just a thought.

  28. Andrew January 15, 2008 at 12:58 am

    As a response to Greg above. What about the Salt Flats of Utah? The West Desert is a wasteland of salt. Perfect place for something such as this and a much better use than that as a place to race cars and test missles. Burning Man might have to move though.

  29. me January 14, 2008 at 11:47 pm

    keep in mind that the current big oil and energy companies OWN most of the current solar cell and some of the other solar companies.

    That said, its time to use the internet like the ending of “chain reaction”, make sure that the info is transmitted to every possible conduit that can carry the truth.

    Any sufficient heat sink (as this appears to be) should be able to counter some of the loss related to sunrise/sunset cycle, which means its a matter of improving how well this works, not just flagging it as good.

  30. John January 14, 2008 at 11:12 pm

    But what about all the big money oil and coal companies? Are they just going to stand by and watch the nation convert to a cheap energy source? I doubt it.

  31. psychic readings January 14, 2008 at 10:50 pm

    thanks for the information..

  32. projectmanagement January 14, 2008 at 5:53 pm

    this kind of news makes me happy in these dark times! Lets start a lot of renewable energy projects…

  33. Nick Simpson January 14, 2008 at 5:42 pm

    Sounds entirely workable… Any means of storing renewable energy, even for a few hours or so, gets past one of the main hurdles – that such sources as wind and sun are unpredictable and/or not 24hr. Energy production is all about predictability and this could be the answer to a lot of problems. Plus as they say, salt is (other than the temperature) a very safe, cheap, available medium to be using. Time will tell, but this looks promising.

  34. Samuel Fredicks January 14, 2008 at 5:05 pm

    It is really a shame that the U.S.A lags behind in all forms of renewable energy. Hopefully a new President and congress will push renewable energies into a new bold direction in 2008!!!

  35. greg January 14, 2008 at 1:37 pm

    Alas that such things are always “10 to 15 years” away. But I confess optimism; this seems a much more believable possibility than many bits of hopeful news we hear. This method of electricity generation is exactly what we need more of. I disagree that the “environmental impact is essentially zero.” The amount of land required is small, but important. The power stations will likely disturb land on site as well as through road contruction, expansion of weed vectors, transmission lines, and so on. I fully support the construction of solar power stations, and the potential for storage as in those decribed here is wonderful, but let us remember that we are playing a game of minimizing out impact, not eliminating it. A series of massive solar power plants and their roads and power lines is not nearly as environmentally responsible as turning down the heat, turning off the lights, reducing your (electric car!) commute…

    Great idea! No substitute for embracing the beauty of LESS. And when we use less AND use the sun… ahhh!

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