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February 11, 2006

A New Chapter Begins for Concentrated Solar Power

Companies break ground on the first Concentrated Solar Power project in more than 15 years
by Jesse Broehl, Editor, RenewableEnergyAccess.com
Boulder City, Nevada [RenewableEnergyAccess.com]

This weekend, in the Desert outside Las Vegas, a major milestone was reached for renewable energy that could represent a shift in how the fastest growing region in the U.S. get its energy. Hundreds of people from around the world were on hand in Boulder City, Nevada, to commemorate the groundbreaking for the beginning of construction on the first Concentrated Solar Power (CSP) energy project in the U.S. in more than 15 years.

"If we want to get serious about reducing carbon dioxide emissions and lower our use of fossil fuels, this is a way to quickly address that. I'm very optimistic about this technology."

-- Chuck Kutscher, Principal Engineer and Group Manager of the Thermal Systems Group at the National Renewable Energy Laboratory (NREL)

Called Nevada Solar One, the 64 MW commercial-scale solar energy plant will encompass 350 square acres, a nearly endless sea of mirrored troughs that will concentrate the strong desert sunlight and convert it into 750-degree F thermal energy, which can then be used to create steam for electrical power generation.

A combination of state policies and support from both the Governor and the legislature, steady advances in this type of technology, all coupled with skyrocketing energy costs have helped make this unique project a reality.

"Nevada has proven to be very forward thinking in promoting solar and other renewables," said Solargenix President John Myles. "The main factor here is that you can get very large blocks of power coming from solar energy in one single location. It is very clearly the lowest cost solar energy that can be produced today."

The project is designed and led by Solargenix Energy, based in North Carolina, but involves a host of companies from around the world. The groundbreaking this weekend also made official a partnership between Solargenix and Spain's renewable energy giant, the Acciona Group, which has acquired a 55 percent interest in the commercial power plant division of Solargenix.

Gilbert Cohen, Vice President of Engineering & Operations for Solargenix, said the project costs somewhere in the range of $220-250 million. He said the power is slightly more expensive than wind power, but less than photovoltaic (PV) power, more commonly used in small rooftop projects on homes or businesses. Other sources close to the project put this price at somewhere between 9-13 cents per kWh. As more are built, however, and they're scaled up even bigger, Cohen says a target of seven cents per kWh will not be difficult to reach in the near future.



The Nuts and Bolts of Nevada Solar One

Germany's glass specialists, Schott -- a company familiar in the solar industry for their solar photovoltaic modules -- is one of the primary equipment suppliers. In its first large-scale solar thermal contract, Schott is providing more than 19,000 of their latest vacuum tube steel and glass receivers, which in many ways can be considered the heart of the project. It is these receiver tubes that the parabolic mirrors focus the sun's energy on and they, in turn, absorb the solar radiation. Flabeg, also a German company, will provide the mirror panels or troughs while industrial giant Siemens of Sweden will provide the 75 MW turbine.

Many other companies are involved in other aspects of hardware and construction, including the main construction contractor Houston-based EPC, Phoenix-based Hydro, which is building the aluminum tracking frames that hold the mirrors. Israel-based Solel is providing some backup receivers in case there are any supply issues with the Schott receivers, according to Cohen. In all, as many as 750 people will be involved in the construction and the power plant will have a full-time staff of 28.

Contrary to some press accounts, the project is not the largest of its kind in the world. Nor is it the first. There are, in fact, nine similar projects in the Mojave Desert in California -- two of them 80 MW in size -- that are operating above and beyond original expectations. According to experts involved in the project, however, there are subtle but significant changes made to this new version that will improve the overall efficiency and cost.



The older plants in the Mojave Desert, called SEGS, for Solar Electric Generating Stations, were different in a number of ways. Those plants required a 25 percent natural gas-fired backup to keep the heat transfer fluid temperature from fluctuating wildly. Nevada Solar One is designed to be more efficient in holding its temperature and requires only a 2 percent natural gas backup. More efficient and reliable motors will be used to move the troughs that track the sun. The frames for these troughs are now built out of lightweight aluminum instead of galvanized steel.

The receivers themselves are different as well. Christoph Fark, global manager for sales and marketing for Schott's solar thermal division, says the close to 19,000 receivers used in the project are the first commercial application of a new design from the company. The receivers must be designed to withstand the daytime highs of 750 degrees F and the lower temperatures at night. This can be particularly challenging to the seal between the outside glass tubing and the vacuum-packed steel receiver inside that holds the heat transfer fluid, a special synthetic oil. Fark explained how Schott invented a type of glass with the same thermal coefficient as steel so the two materials would react in unison to the constant temperature stresses.



These complex receivers are currently made in Germany but if CSP technology becomes a bigger player in the American Southwest, Fark suspects they could move some production into the U.S.

"We see this as the beginning, we are involved in project discussion worldwide -- such as the southern parts of Europe, the Mediterranean and the Middle East," Fark said. "We hope the market picks up, and if so, then Schott is willing to invest in the production side in the U.S. This is our overall strategy, to be where the customer is. We believe the U.S. market offers huge potential for this technology."

The Right Place at the Right Time

On a broader scale, Nevada Solar One reflects a symbolic rekindling of this technology approach, one that many experts say is particularly well-suited for areas like the American Southwest where sunlight is abundant but energy is precious and increasingly strained by population growth.

"This is a technology the utilities are comfortable with, it has proven reliability, it lends itself to economies of scale, there clearly is still some room for price reduction, and also it's a way to get large amounts of renewable energy deployed rapidly," said Chuck Kutscher, Principal Engineer and Group Manager of the Thermal Systems Group at the National Renewable Energy Laboratory. "If we want to get serious about reducing carbon dioxide emissions and lower our use of fossil fuels, this is a way to quickly address that. I'm very optimistic about this technology."

A wide variety of factors have collided -- everything from politics to the marketplace -- to make this project a reality.

"After many years the time has come where we don't have to explain anymore the need for renewable energy, we don't have to explain the concerns about climate change, we don't have to explain the instability created by oil resources that belong to only a few countries when all countries are using these resources. Nor do we have to explain the instabilities to energy from disasters like hurricanes," said Alberto De Miguel, Acciona's Director of Corporate Development and Strategy. "Renewable energy is now accepted more than ever by the public."

And that public acceptance is increasingly being turned into policy. Nevada is one of a growing number of states with a mandate that electric utilities, in this case Nevada Power Co. and Sierra Pacific Power Co., source a slowly escalating percentage of their power from renewable resources. Eventually the two utilities will have to reach 20 percent renewable energy use by 2015. The law also contains a so-called "solar cut-out" that requires at least one-fourth of that power to come from solar energy. The project is projected to generate 130,000 MWh of power per year over the course of its decades-long lifetime. All of its electricity production will be sold to Nevada Power and Sierra Pacific Power under long-term power purchase agreements to help them meet this requirement.

A Natural Fit for Tomorrow's Market

While Nevada's policy played a very strong role in supporting this project, perhaps the next most influential factor is the natural gas market where prices have skyrocketed. This is at the core of why experts inside and outside of Solargenix believe CSP will play an increasingly important role in helping the rapidly growing American Southwest to meet its energy demands.

"There are fundamental differences in the electricity marketplace versus 15 years ago," said Rhone Resch, Executive Director of the Solar Energy Industries Association (SEIA), who was involved in the natural gas industry before joining SEIA.

"Natural gas and peak power is incredibly expensive. Utilities are scrambling to find power generation sources that are reliable for peak power," Resch said. "Those changes are going to be what drives new plants like this. The beautiful thing with this project is that it offers firm, dispatchable peak power."



Resch said utilities and the ratepayers they serve made an investment in natural gas for the coming decades as a transition fuel but they are finding out now that it's too expensive to afford. The power plants are fine, but the energy commodity is becoming cost prohibitive and coal is often the next best option. This is relevant and fortuitous for CSP technologies because natural gas power plants are not fundamentally so different than a CSP plant. Just as today's fleet of natural gas plants uses a fossil fuel to create steam for a turbine, CSP plants like Nevada Solar One also create useable, commercial-scale steam, except only from the sun's energy, a consistently free and available resource.

"Except for the troughs, everything else is a standard natural gas plant," said Scott Sklar, industry consultant with the Stella Group. "That's what Solargenix has always maintained, you're really buying a natural gas power block with solar attached. It can't be that risky, after all the old SEGS plants have been up and have operated close to flawless."

In addition to the power plant side of the project being something the utilities and the traditional power industry is familiar with, Sklar said these types of projects can be easily deployed close to where the power is needed, unlike commercial wind power where the best wind resources are often not near where the power is needed. And while wind power may offer a slightly lower cost per watt than CSP, wind power generation is intermittent, whereas CSP offers consistent power all day long when energy demands are highest.

"I dealt with this all the time, in the early days when Washington pundits and other people thought solar thermal would go nowhere," Sklar said. "Or they would say 'this stuff is great but it just isn't in sizes big enough to matter.' Well this is pretty substantive. It's exciting and I think it will create a whole revival towards concentrated solar power in the U.S."

The project is scheduled to begin production of electricity in March of 2007.
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Reader Comments (23)
 
No image available
February 11, 2006
Just read the article; it is all there. Well written, good project and I hope we have many more of the same.

adrianakau@aol.com
Comment 1 of 23
No image available
February 12, 2006
In response to Rich Barbarics, there is not enough photovoltaic modules available to do that. The military is had a hard time finding enough for a 18 MW plant. It will be years before production catches up to demand and some plants need to be built now. If solar thermal were not available, natural gas or coal will be the only alternative. Also, solar thermal is cheaper per kilowatt (plant construction) and per kilowatt hour (energy cost). Solar thermal has more economies of scale, as well. Cogeneration, perhaps the biggest advantage of distributed generation, is not used in photovoltaics or solar trough (although it could be used in solar trough). The only downside of concentrated generation, in this case, that I can think of is if the plant had to be located so far from the consumers of electricity that a significant amount of electricity is lost. However, that is not the case for these plants.
Comment 2 of 23
No image available
February 12, 2006
Dish Sterling systems today are far more expensive and certainly in no way as proven as trough plants. It is hoped that cost reductions will come with large scale automated mass production. As of yet, no large or even remotely large scale dish plant has been built, much less accumulated sufficient operating experience to reasonably predict longer term costs. They should be somewhat more efficient than troughs since they operate at higher temperatures, but the relaibiilty of all those motors and trackers at the 100 MW+ scale seems to me problematic.
Comment 3 of 23
No image available
February 12, 2006
Sure, lift the cap on PV, but don't stop building parabolic trough plants! They are more efficient than PV and less than half the cost.

There is nothing wrong with a mix of large central station and smaller distributed generators. We need both - a lot more of both.
Comment 4 of 23
No image available
February 12, 2006
Does anybody know how the solar thermal troughs compare in cost/efficiency/reliability to Stirling CSP technology? As far as I know, Stirling CSP doesn't need backup natural gas and the solar energy is transfered directly to the working fluid instead of going through multiple steps.
Comment 5 of 23
No image available
February 12, 2006
The Nevada solar incentive program for distributed generation is capped at 1.9 MW per year yet this huge central plant is 64 MW. Why don't we increase the distributed portion of generation by higher capacity rebates and better production credits and reduce the amount of large scale central generation plants? The computer industry is a good model to follow. from mainframe to distributed processing, now the norm.
Comment 6 of 23
No image available
February 12, 2006
Solargenix and Ormat have built a concentrated solar power plant that is operating in Arizona.
The plant has an installed capacity of 1MWe.
The plant is owned by Arizona electrical company APS and uses Ormat's turbine that have been very successful in the geothermal power production.
http://www.hydrogennow.org/HNews/PressReleases/APS/APS%20to%20Construct%20Plant%20in%20AZ.htm

Ormat also built a high temperature high efficiency solar powered gas turbine:
http://www.solarpaces.org/sol-gate.htm
http://europa.eu.int/comm/research/energy/pdf/cst_en.pdf
http://europa.eu.int/comm/research/energy/pdf/solgate_en.pdf
Comment 7 of 23
No image available
February 13, 2006

It's because the German's aren't using CSP that the demand for Si is so high and that the price of PV panels has gone up! Perhaps CSP isn't feasible in German but it seems silly to suckup all of the PV modules that could be used for DG and use them to make puny 5MW plants. The two sterling projects that are going to be built in so cal dwarf what the Germans have done up to this point without creating global shortages.

It's great to see new CSP installations. I'm sure that we'll see more of them in the coming years in many parts of the west.
Comment 8 of 23
No image available
February 15, 2006
Is the company quoted at a stock exchange
and if, where and with which ticker symbol.

Best Regards

Guenther Sigel
Comment 9 of 23
No image available
February 15, 2006
For Peter Marsh - The system could use the grid to send power one solar hour in either direction. In the early morning, send it west, in the late afternoon, send it east. At mid-day I would guess they are happy simply to replace fossil power because of CSP's basic cost advantage.

For Garry Barbuto - Hydrogen? "the perfect energy storage medium and fuel"? It is neither perfect nor a fuel in any sense.

Hydrogen will always be an expensive carrier of a fraction of the energy in the fuel that was used to produce it. Its function is exactly analogous to that of a rather poor electric battery.

It is clean to burn, but never efficient to make. And the "Hydrogen Economy" is a really despicable piece of energy-industry fiction.
Comment 10 of 23
No image available
February 15, 2006
I must firstly say that I am impressed by the project that is announced. Pardon me for asking what may be a dumb question, but if you look at solar radiation intensity figures averaged out over a year and on an hour by hour basis, the major solar insolation window effectively runs for four to six hours from 10:00 AM until 2 - 4 PM. I cannot see a system for storing the heat generated from this system and therefore assume that as the heat is generated it is going to be converted into electricity.

Peak electricity loads occur between 7-9 AM {when people crawl out of bed and get ready for work} and from 6-9 PM when they come home from work and turn on their air conditioning.

How exactly does this system propose to fit that real world requirement?
Comment 11 of 23
No image available
February 15, 2006
I was wondering why they are using a Rankin Cycle system to produce electrical power. Sterling engines are more efficient overall and can turn heat energy directly to mechanical, no heat exchangers/boilers etc. There are units out there using parabolic dish 2 axis tracking that produce 25 KW electrical. The other issue with Renewables is the often sporadic nature of the supply. That is why Hydrogen is the solution to this problem with renewables. Hydrogen is the perfect energy storage medium and fuel.
" Hydrogen Makes Renewable Doable"

Regards

Garry
Comment 12 of 23
No image available
February 16, 2006
Just doing a little digging around for cost of power produced:

Solargenix CSP: 9-13 cents per kWh (source: this article)
Stirling Energy Systems CSP: < 10 cents per kWh for 1000MW installation (source: http://www.stirlingenergy.com/faq.asp?Type=all)
Wind power: between 4 and 6 cents per kWh (source http://www.nrel.gov/wind/working.html)

Of course, if there's no wind in the desert, use CSP.

Stephen
Comment 13 of 23
No image available
February 17, 2006
Vegas could use as much natural electricity as possible?! Yucca du-du must be full by now?
Comment 14 of 23
No image available
February 17, 2006
Re: "...the power is slightly more expensive than wind power, but less than photovoltaic (PV) power..."

I see some people discharge solar PV as a solution for solar to electric? The investors have already go through this exercise, and learned their lesson. PV solar is on of (if not the) fastest growing high-tech sector.

As for the concentrated solar to electric solutions, if one uses the high concentration Vertical Multi-Junction (VMJ) solar cells (developed by Bernie Satter of NASA GRC), and low-cost Fresnel lenses, I strongly believe the VMJ-based compact systems will produce a lower price/KWh of electricity than most solar thermal to electric solutions.
Comment 15 of 23
No image available
March 15, 2006
I want to understand how this works!

I have studied the schematic for how this system works and have some questions as I am having a spirited discussion with my Son on the fundamental physics of this process. Would someone be so kind as to fill in the missing pieces so that we can better understand how the system works.

What are the temperatures expected throughout the system, namely...
1. Turbine Generator {mentioned to be ~750C}
2. Condenser input
3. Condenser output.

And on the two inputs/outputs
1. Return for parabolic dishes
2. Cooling tower input
3. Cooling tower output

Another fundamental concept I am uncertain about. At the bottom of the diagram, the arrowed flow in the main circuit shows "Steam". Should this not be "liquid" or is the evaporant {Water} never returned to its liquid state in this system? Why not? because I would have thought that the greatest change in its mechanical energy would be when you tranform water from a liquid to a gaseous state.
Comment 16 of 23
No image available
June 6, 2006
For Peter,

It might help to understand that the fired boiler is a means of generating power when the sun isn't shining - you can simplify the design for illustration by ignoring the fired boiler (or the solar boiler if you prefer - in which case you have a standard NG turbine).

It is a simple rankine cycle turbine (heat -> steam -> turbine -> cooling tower ->repeat)

Your question as to the temperature coming off the solar system is a good one. These concentrators run in the low hundred(s) of suns. If one sun can reach 100 degrees F, than 100 suns can approach 10,000 degrees, but 2,000 degrees is fairly standard for turbines.

Whether or not the working fluid condenses to a liquid is a good question. Rankine will probably work at any temperature, but the most effecient set of temperatures have long been studied. I suspect the diagram is right, and let's hope someone has the temperature diagram handy.

Ben
Comment 17 of 23
No image available
March 19, 2007
The Feb. 17th remarks by Dr. Faur regarding the low $/kWh potential of PV concentrators using high intensity vertical multi-junction (VMJ) cells were appreciated. Silicon VMJ cells have demonstrated efficient performance at intensities greater than 1000 suns (www.photovolt.us), meaning the silicon in 1 MW of conventional PV modules could make 1000 MW of PV concentrators with a significantly lower $/watt cost. (This would be a simple and low-cost way to eliminate silicon shortage problems.) The technologies to make PV concentrator power cost-competitive with coal-fired power are now proven but require the right leadership and commitments to make it possible.
Comment 18 of 23
No image available
March 21, 2007
Peter, the figure is definitly wrong (missleading if you want to be kind). The condensor changes the steam to water, which is pumped to a high pressure by the pump just above the word "steam" in the figure.

Incidently, Ben, 100 suns will Not produce 10,000 degrees. First you have to start in Absolute temperature (O deg F is -460 deg Rankine. Then remember that the primary loss in a concentrating system is radiation, and it increases at the fourth power of temperature. So if 1 sun = 560 deg R, 100 suns is 1452 deg R, or about 1000 deg F. One should also worry about convection, etc, but this is in the ballpark.
Comment 19 of 23
No image available
April 9, 2007
Does anyone have a sense for the smallest feasible size for such a unit? In the 10kw range, could this ever compete with conventional pv?

If not, would someone mind pointing me in the direction to follow this type of discussion further?

Per
Comment 20 of 23
No image available
April 13, 2007
Per, here's an article on small-scale concentrating solar: "Soliant Energy Targets Commercial Rooftops with its Concentrating Solar Platform"
Comment 21 of 23
No image available
September 6, 2007

The good news is that this demonstrates that you can boil water without using nuclear.  Essentially, building a better tea kettle.  We have clowns trying to site for nuclear power here in California.  They also are gathering signatures for a ballot initiative for June 2008.  Fortunately, Wall $treet won't buy a "Nuke" until Washington DC ponies up $1 Billion dollars just to underwrite a "hard target". GAME ON!

 


Comment 22 of 23
No image available
November 23, 2007
regarding to all replys i have an important question:

how is the tarriff calculated for 1kw of solar energy?

in other words what are the elements that usually construct the tarriff in solar power.

because a lot people thinks that the tarriff in the US which is 9 - 13 cent will be the same in Dubai for example.

i hope from any body that can help puts a comment or direct me to where i can find an answer.
Comment 23 of 23
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