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World’s largest solar thermal plant now fully operational


February 17, 2014

The world's largest solar thermal generation plant, Ivanpah Solar Electric Generating System, is now fully operational

The world's largest solar thermal generation plant, Ivanpah Solar Electric Generating System, is now fully operational

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After three years of construction, the Ivanpah Solar Electric Generating System (ISEGS) is now operational. The 392 MW plant, funded by NRG, Google, and BrightSource Energy, is expected to generate enough electricity to power 140,000 homes, each year. NRG announced last week that each of the plant's three units is now supplying electricity to California’s grid.

The Ivanpah plant cost US$2.2 billion to build and stretches over 3,500 acres (more than 1,400 hectares). ISEGS is the largest solar power plant of its kind, accounting for nearly 30 percent of solar power generated in the US. It uses 173,500 heliostats (computer-controlled mirrors) that follow the sun’s trajectory and reflect its light towards three solar receiving water boiler towers. The boilers superheat steam to temperatures of up to 550° C (over 1,000° F), which drives standard turbines to generate electricity.

The electricity produced by Units 1 and 3 at Ivanpah, accounting for 259 MW, is being sold to Pacific Gas & Electric under two "long-term power purchase agreements.." The remaining 133 MW generated by Unit 2 is being sold to Southern California Edison with similar terms.

"Cleantech innovations such as Ivanpah are critical to establishing America’s leadership in large-scale, clean-energy technology that will keep our economy globally competitive over the next several decades," says NRG Solar's president Tom Doyle. "We see Ivanpah changing the energy landscape by proving that utility-scale solar is not only possible, but incredibly beneficial to both the economy and in how we produce and consume energy."

Ivanpah's construction has not been without controversy. Its huge scale means that a great deal of open land has been used, which had previously been the preserve of the native flora and fauna. Furthermore, there are continued reports of birds being killed by flying into the mirrors or being scorched to death as they fly over the plant.

Eric Davis, assistant regional director for migratory birds at the US Fish and Wildlife Service’s Sacramento office has been reported as saying, "We're trying to figure out how big the problem is and what we can do to minimize bird mortalities. When you have new technologies, you don't know what the impacts are going to be."

The California Energy Commission has stated that while Ivanpah will impact the local environment, its benefits outweigh the disadvantages.

Sources: NRG, BrightSource Energy

About the Author
Stu Robarts Stu is a tech writer based in Liverpool, UK. He has previously worked on global digital estate management at Amaze and headed up digital strategy for FACT (Foundation for Art and Creative Technology). He likes cups of tea, bacon sandwiches and RSS feeds. All articles by Stu Robarts

Maybe they can keep the birds away with an array of huge, fan-inflated, arm-flailing scarecrows around the plant.


Essentially you've shown that it cost around $5600 per kW, which is expensive for a power plant but not unreasonably so. The value comes in that there's no fuel to burn. It's like building a dam, but without the concerns over fisheries. Now if we can just loft a solar reflector in geo-stationary orbit so that it produces at night, its productive capacity will increase by at least double, if not more (accounting for losses for when the sun's up, but the angle is too low).

J.D. Ray

$2200000000/392000000W = $5.61/W. Ouch, but if you have the money that's of no concern. I wonder what the balance would have been verses a PV set up? The birds would have been better off at least ;) Still, "clean" (why say green?) energy is still a lower cost than burning stuff.

Craig Jennings

Wouldn't that be $5.61/W *this year? Then $2.80/W next year (+operating costs) $1.87/W (+ operating costs) the year after ... and so on.


On the type of power plants I work on (DO and HFO), fuel represent 70 to 90% of the life cost... Short term calculations are pretty blind to facts.

Gildas Dubois

This solar plant might be the last of its kind. Prices of photovoltaic cells have fallen so much it is not feasible to build csp thermal plants anymore.


There should be a significant amount of shelter and shade created UNDER the mirrors, so I predict that some local wildlife will benefit greatly and others not so much.

You win on the roundabouts, you lose on the swings.

How do they keep the mirrors clean?


Given that solar is now $1/W, this would not appear viable on face value.

But it doesn't add up in my mind. In reality as with any 'different' project, all the costs were bloated to hell, and every man and his dog made money on it, as usual. And big oil as usual is smiling in the background.

A solar concentrator is essentially a steam engine on its side, with mirrors focussing the sun on its boiler. As such it should cost no more then the land, labour, iron and fabrication of the materials. The whole thing can be made modular for cheap overseas and imported.

If people were serious (and there was no influence in the background to keep status quo) these things would be peppered all over the place and costs would be around the $.5-1/W

If they really wanted to double wammy it they would combine the concentrating mirrors with lower efficiency solar panels, which would work in a roundabout way because the head would reflect back some of the light, which would get picked up by the panels a second time.


Around $5500 per kw, vs around $1500-$2500 per kw for a brand new coal-fired power station-& between $2500-$3500 per kw for a brand new gas-fired power station. That's not too bad, especially when you consider that this price will come down as more such facilities get built (material costs in particular). Also, as JD rightly points out, that price differential will level out quickly given the lack of ongoing fuel cost & waste disposal costs (millions of tonnes of fly-ash waste are produced every year by coal-fired power stations, waste that needs to be disposed of, safely, as its usually laced with heavy metals & even radioactive materials). I am curious, though, as to whether they did the smart thing & installed salt storage tanks, as molten salt would allow this sucker to run 24/7, for a few days, without any additional sunlight.

Marcus Hicks

This facility would be no greater threat to bird populations than a single high-rise building.

Marcus Hicks

What ever happened to using sodium as the heat medium instead of steam? Sodium can store enough energy on a sunny day to also radiate it back through the night.

Simon Sammut

I hope they can keep it going in the long term ... down-time for repairs to the boilers/generation systems could eat into efficiency a little. If nothing else, the savings on coal mining or gas extraction - and transport costs - and then waste disposal should bring the running costs down the longer it runs. After a little while, the 'dumb' birds will not be there to get killed, the 'smart' birds soon learn to avoid skyscrapers and office blocks already, so that complaints on that score will also lessen.

The Skud

Not so bad. Let's say that the station costs 4 times more than a coal plant, but having in mind, that it would not consume fuel, this should weigh the equation in their favor.


there are new technologies coming that will improve such electric power stations http://www.gizmag.com/ibm-solar-collector-reaches-80-percent-efficiency/27256/

Mariusz Gyan

I agree with Khoop - the continuing cost will go down each year (baring maintenance). So the original high figure that someone worked out is only for the initial year. Hopefully it will be maintained and the technology upgraded to make it even more efficient. Well done U.S. Can we have cheaper reproduction plants here? We could use wind generators in the areas were they could be positioned (we have a lot of wind and weather at the moment in the UK!) However 'scorched to death as they fly over the plant' is a tad scarey - hopefully they are trying to sort this out!


Solar plants only work when there's sun. Turbines are best in strong(er) wind. Tidal also has the same problem. Coal, gas and nuclear are on-demand, but they have problematic environmental concerns. Hydro isn't perfect, but seems top be the best and most effective energy source at the moment.

The secret to the success of renewable energy is in efficient storage. The earth is the best battery device. Geothermal is the way to go. If all the attention went towards this possibility, we would see a remarkable benefit to the planet and people. Some steps forward have already begun in Iceland, but it needs to get universal asap.

But Big Oil won't ever let that happen. What people need to do is to rethink this harmful and wasteful cycle of energy procurement, the sooner the better!


In the utilities world, it is about predictability. Without it, you can't plan and buy/sell utilities...All electrical utilities are currently produce/sell at least 24 hours in advance.

We can say how wonderful these green tech are. They are NOT reliable and can't really be reliance upon.

Luan To

392 MW plant, with an ave of 6 hours useful sunlight per day= 2,352 MKWH/year. With a build cost of $2.2 billion over 20 years, equal to $2.2e9/(20x2,352e6 kwh)=$0.0467/kwh. Not a bad rate/kwh

But I am a bit confused by the number of homes claimed to be able to operate. Taking the yearly output (2,352MKWH) divided by the average 10,000 KWH/household in the us gives me 235,000 homes, not 140,000 homes. Using 140,000 homes figure, this would be equivalent to 10,000 sq ft needed per home, which is way over what is needed in most climates (roughly 1000 to 2000 sq ft of solar) depending on the homes energy performance.

Can someone clarify?


What's missing here is any mention of carbon emissions - or lack thereof. As if reduction of greenhouse gases in energy production wasn't a design goal of this power plant. In 2008 Tufts U. researchers Ackerman and Stanton, published a figure of $120 billion for the "hidden costs of fossil fuel" use. Chances are that number is higher six years later.


392 MW? That mean what exactly, the peak power, the average daytime power , or the average power at anytime. There is 8760 hours in one year and electricity is sold by KW/h or MW/h. Considering what is written above, how many MW/h can be produce per year with this power plan? Also the selling price could be deceptive, spot price can be anywhere between 20 an 60$ per MW/h, and can go much higher during exceptional circumstance, however long term agreements are usually a fraction of the number mention above, and the term of the contract could be misleading. Price "on demand" or "take it or pay for it" are two totally different animal. So, after reading the article, i'm still totally clueless about the numbers. I don't even have a slightest idea on how economically sound the project really is or not.


One thing I never see in articles about steam solar plants is how much water they use. A lot of water is needed to condense the steam plus water is needed to wash the mirrors. I would like to see how much water per KW is used.


I can see something better to do with the 3,500 acres.

(Capture CO2 from the air) - Grow a low maintenance plant, like a native grass or shrub or tree, something that does not require additional fertilizer.

Harvest the plants.

(Return CO2 to the air) - Burn the plants, generate steam, make electricity.

This solution should be probably more carbon neutral than maintaining 173,500 mirrors plus this solution can produce power when the sun is down.

Or better yet, grow food.


This is a great technological accomplishment and should generate clean energy for generations to come. However, I question whether these "mega" solar installations are really the smartest investment for the future.

The “central power plant” mentality not only takes up massive amounts of virgin land (the Ivanpah project is 3,500 acres), which does disrupt the ecosystem but it also relies on a very vulnerable Grid System to deliver the energy to the 140,000 target homes that are hundreds of miles away from the site.

Would it not be wiser to invest in smaller more localized PV projects utilizing available rooftops and parking lots throughout the cities and forming micro-grids? These Micro-Grids would be less vulnerable to interruption due to natural or manmade disasters and thereby eliminating massive power outages. These Micro-Grids could be augmented/backed-up by small neighborhood “Fuel Cell” generation plants strategically located in a sort of honeycomb pattern and interconnected in a way that if one unit failed only the houses and businesses within that one honeycomb cell would be affected.

There are also environmental upsides as well: a). because the solar panels would be roof mounted or on poles in parking lots, the Sun’s heat would be absorbed by the panels with the excess being reflected back into the atmosphere and therefore lowering the “Heat Island Effect” b) pole mounted PV panels in parking lots would provide needed shade for pedestrians and mean that automobile interior’s would remain cooler and utilize less air conditioning energy and fuel when restarting the auto, c) Birds are less likely to be injured by PV and in fact the underside support infrastructure would make an ideal nesting habitat for urban birds, d) the property owners could share in the financial gain by lowering their own utility costs, as well as, supplying clean energy to their immediate neighbors who, most likely are also their customers.

Please note that I fully understand that the above scenario is lacking in specifics and details but is only meant as a more logical alternative to the continued building of centralized power generating facilities for the masses.

Craig Ruark

Craig: No one can predict what the wisest use of assets will be. That is why centralized control, divorced from economic consequences, always fails. Only two fundamental economic systems exist. Unfortunately, the only one that works, the free market, has never been tried. The centralized, authoritarian system has been tried over and over, in many countries, and failed. So the free market system subsidizes the socialist model, and also provides a "whipping boy" for every economic problem created by the socialist schemes. This mixed economy system slowly morphs into the authoritarian model because it allows concentration of power and wealth for an elite. The end result is always economic collapse. And the cycle starts again. The productive members of society are their own worst enemy for allowing the socialist parasites to claim the moral high ground. Taxation (theft) and regulation need to be identified as evil. No compromise will work.

Don Duncan

Why is it that almost no one seems to understand units of power? I see mistakes in almost half of the articles I read on the subject. And here's another: "...is expected to generate enough electricity to power 140,000 homes, each year." And what happens after a year? Does it stop? If the output of this system can power 140,000 homes there's no time component in the statement; it just powers that many homes... permanently. I see things like "This windmill produces 10 Kilowatts per hour". That's like saying my car has 300 horsepower per hour. These mistakes are almost as common as people spelling "lose" with two "ohs". Just trying to help. 8^)


Hey Warren52nz, the other component that no-one mentioned in the aggregate was the savings from elimination of coal mines, coal processing, coal transportation, CO2 production, pollution beyond just CO2, the waste fly ash was mentioned, but not the bad health effects and that significant cost of polluted air. People who point to killed animals failed to mention animals poisoned from toxic ponds (small lakes) of polluted water at mine sites. The anti-centralized power critics fail to consider how all the civic buildings & schools and industries are served by centralized power produced on a large enough scale to meet the need. Another commented on "power for the masses" as if they think the elite produce energy out their expletive deleted. I happen to be a once millionaire myself now working on a new fortune, and no-one of wealth whom I know has their own "power station" at their home. They are also hooked to the grid, just as they breathe the same air. I did like that one person suggested mirrors in space in a geosynchronous orbit for 24-7-365 light...and others suggested heat storage using salts....but all would do well to grasp the STAR we orbit is 3 million times larger than our planet and is a thermonuclear fission power plant...its energy is an inexhaustible infinite supply to us puny humans. We could harvest so much energy in a few hours we would run for days on the heat alone (the CSP facility in Spain absorbs so much heat that it can run for 15 hours after the earth rotates away). It is truly stupid to dig holes and inject toxic poisons into the earth to frack for gas to run power plants. We could string mirrors on roof tops downtown to heat a central tank to make steam turbine electricity. The CSP energy collection is silent, passive and non-polluting. Furthermore the land under this CSP is desert, not cropland. And BTW there are bil;lions of gallons of water used to cool steam at a coal fired plant and even more at nuclear plants. Why can't these plants be designed to cool the steam & condense it with air cooling instead of using precious water? On the other hand being as we are just cooling steam, why can't the "waste" water be used for human & animal needs? For my ta dollars I see Solar as vastly superior to coal or gas or oil. Oh and I also prefer electric vehicles and solar panels for my home....so we can reduce the need for so many huge facilities by living a more intelligent lifestyle. Plus we put solar PV on schools & churches... and could do much more of that. Question then is, why do we dirty deadly polluting need fossil fuels at all?

Donald Eyermann

If you are visiting Las Vegas, this is worth a trip to see, absolutely amazing.

Chris Casey

where I'm at, the government wasted +- $3.1 BN last year... it's just gone, missing... and no one can show a thing for it...

to think, we could have had an even larger one of these, and still some change left over for washing all those mirrors.

Michiel Mitchell

More of this type of plant might be built because it can also generate fresh water as it generates electricity with only a tiny loss of efficiency in generating electricity.

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