Clean Power Abu Dhabi concentrating solar power photo by Tina Casey

Published on January 17th, 2016 | by Tina Casey

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Solar Power Plant In Oil-Rich Abu Dhabi Beats Expectations — Again

January 17th, 2016 by  

When one of the world’s largest concentrating solar power plants rose from the desert sands in the Western Region of the Abu Dhabi Emirate back in 2013, more than a few heads exploded. Aside from being the site of much of the Emirate’s oil and gas reserves, the western desert is a harsh environment for massive, precisely engineered renewable energy facilities, and concentrating solar technology still has yet to prove its competitiveness in the general market. However, in its first year of operation, the so-named Shams 1 plant beat expectations by a wide margin, and its second year figures are also better than predicted.

So… does concentrating solar power (CSP) have a future? CleanTechnica had an opportunity to tour the plant* and speak with Abdulaziz Al Obaidli, General Manager of the Shams Power Company, who gave us some insights into the keys to its success, and the prospects for future CSP development.

The Shams 1 Concentrating Solar Power Plant

Shams 1 is a 100 megawatt facility with 258,048 mirrors arranged in parabolic troughs covering 2.5 square kilometers. It’s the only plant of its kind in the world completely surrounded by a solid wall…

Abu Dhabi concentrating solar power photo by Tina Casey

…and that’s a critical difference between Shams 1 and other concentrating solar power (CSP) plants. As explained by Al Obaidli, the wall provides a significant measure of protection from desert wind and sandstorms. Storm-grade winds can take out large sections of equipment in a conventional CSP plant, but according to Al Obaidli, one of the strongest storms in recent memory passed through last year and it only damaged 20 out of the 258,048 mirrors.

The parabolic troughs themselves also include design features that prevent wind damage. On just a few minutes’ notice they can be rotated into a “safety” position, and then locked in place.

Abu Dhabi concentrating solar power photo by Tina Casey

CleanTechnica has been following the solar facility since it first cranked up operations back in 2013. In January 2015, we summed up the figures for 2014, the first full recorded year of operation:

The largest concentrated solar power project in the Middle East, Shams 1, has performed better than expected, the Shams Power Company has reported.

[snip]

The company had expected to generate about 193,000 MWh electricity in 2014 but managed to generate just under 215,000 MWh. This translates into an increase of 12% over the expected generation…

In a February 2015 followup piece, CleanTechnica toured the facility as a guest of Masdar, Abu Dhabi’s government-supported cleantech corporation, taking note of the high winds and water scarcity issues.

During our new visit on January 16, 2016, Al Obaidli gave our tour group a rundown on the figures for 2015, and they confirm that the first-year achievement was no fluke. Though the solar plant’s “nameplate” capacity is 100 megawatts, in peak summer days during 2015, it often climbed up to its maximum of 125 megawatts.

In terms of gigawatt-hours, the 2015 production target was 210 and the plant actually generated 216.4, beating both its target and its 2014 mark.

The improved performance can be ascribed partly to the plant’s rather modest control room, which sports a few computer stations rather than an array of switches and dials:

control room solar power plant

Controllers are constantly monitoring and adjusting the system as needed throughout the day, so a good deal of learning and fine tuning take place during the first years of operation. One critical period occurs in the hours after dawn, when solar radiation increases quickly. The troughs must be brought online gradually in order to achieve maximum efficiency without being damaged by the rapid increase in temperature. To that end, power production doesn’t begin until about an hour after sunrise.

Speaking of temperature, that brings up another challenge faced by Shams 1. The CSP supply chain has broadened and matured in the last several years, but when the plant was constructed the supply chain was razor thin. Many components were manufactured in Europe, where they were not exclusively tailored for high heat and extreme day-night temperature swings.



 

They Don’t Do Windows…But They Will Do 258,048 Mirrors

One key feature of Shams 1 that both Al Obaidli and plant manager Borja Sanz Limon brought to our attention was the mirror washing system. Washing is a critical feature of efficiency for any type of solar system, so keeping solar surfaces free of dust and debris is imperative.

While sprayed water and/or rainwater can help keep solar surfaces clean in more temperate areas, at Shams 1, the lack of rainfall combined with the high level of dust make a brush-based system necessary for each wash. The brush system must also be sophisticated enough to deal with the unique challenges of washing a curved surface that is bisected by a somewhat delicate, glass-enclosed pipe.

The solution is a fleet of five washing trucks sporting robotic arms that are tailored to the troughs, which are put in “washing” position (washing position is not the same as the safety position, by the way) each night. The truck driver gets into position parallel to each trough and drives very, very slowly alongside, and the arm automatically adjusts to any slight weaving that occurs so as not to bump into the piping. All that sophisticated equipment adds up to about $500,000 per truck:

solar washing trucks

That’s quite an investment, which explains why the mirrors are cleaned on a weekly cycle. The relative loss of efficiency by day 6 has to be balanced against the capital investment in a larger fleet, and a fleet of five is apparently the right balance.

All this TLC is expected to pay off in terms of achieving the plant’s intended lifespan of 25 years, which so far it is on track to achieve. In the meantime, it is also achieving the goal that a carefully engineered CSP can not only survive but thrive in harsh, dry conditions. As Al Obaidli put it to us:

This is a commercially successful project. In the middle of the desert, we were able to produce what we were supposed to produce, and even more.

How Does CSP Survive Without Solar Storage?

We had buttonholed Al Obaidli after his presentation to ask about solar storage, and this is where things get interesting.

While the price of CSP has been dropping, photovoltaic cells have dropped much more. So, by the raw numbers, CSP is not keeping up. However, the recent emergence of solar storage into the marketplace can provide CSP/storage systems with a leg up.

The problem for Shams 1, as Al Obaidli explained, is that back in 2010, when the plant was still in development, solar energy storage was not fully embraced by the marketplace.

The storage element added yet another wrinkle of risk onto the plant, which was already considered a high-risk venture for a number of factors: using CSP technology, being built in the desert, using natural gas to boost the efficiency of the steam turbine (more on that in a second), and using air instead of water to condense the steam back into liquid (conventional water-based cooling accounts for 90% of water consumption in a typical steam turbine power plant, so water cooling in the desert is a non-starter).

In 2010, storage was the straw that broke the camel’s back, so the decision was made to go ahead. Although the plant does not generate electricity at night, as a grid-connected facility, it helps reduce the need to build new gas-fired power plants to meet growing peak demand periods in Abu Dhabi, much of which involves the use of air conditioning during the summer months.

Solar Power With A Fossil Twist

While the use of natural gas at a solar plant may disappoint solar fans, the reality is that fossil fuels are going to be in use long into the future, though they will necessarily play a much smaller role than they do now. As a parallel, consider that history of firewood for household heating has not yet finished unspooling, even in many industrialized countries.

In that context, Shams 1 provides an illustration of how fossil fuels can deployed conservatively in tandem with renewable energy. The plant’s operating permit caps the amount of gas it can burn at 600,000 Btu per year, and in 2015 it was able to operate well within the limit.

More generally, Shams 1 demonstrates that renewable energy facilities are not one-size-fits-all, but can be tailored to leverage resources that are specific to each site or region, enabling another path to using less fossil fuel, to greater effect.

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All photos by Tina Casey.

*The Shams 1 tour was on CleanTechnica’s activity list as guests of Masdar for Abu Dhabi Sustainability Week 2016, and this is the first of a series of reports we’ll be filing about the event.

 
 
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About the Author

specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.



  • kirk jackman

    I am delighted to see any media
    coverage giving hope to alternatives to fossil fuels. Thanks.

    As a solar engineer in Costa Rica I’d like to comment
    on a few details you mentioned in your article in order to possibly
    support an even clearer presentation in future articles.

    In your article you mentioned:

    “concentrating solar technology still has yet to prove its competitiveness in the general market”.

    From a dollars and cents viewpoint this
    is true. The term ‘general market’ is a bit of ‘new think’ that
    leaves some important details behind. I would invite you to offer
    future articles which might bring more awareness to the ‘real cost’
    of fossil fuels, including environmental costs [pollution, carbon dioxide, war, etc.] of any technology, PV or otherwise. My own work is in CSP, as I see it’s
    current ‘total cost’ as less than fossil or PV. I realize we are in
    an epoch of transition technologies and must explore all
    possibilities knowing that each one can offer unexpected
    breakthroughs.

    I’m all for mixed technologies.

    In your article you also mentioned:

    “The plant’s operating permit caps the amount of gas it can burn at 600,000 Btu per year”.

    This seems unreasonably minuscule, about 0.08% of the annual energy output. A single employee might use more energy in his/her car just commuting to work on one day or so.

    FYI – a typical home furnace is rated at 80 to 100 thousand BTU per hour. The number you presented is about what a typical house in North America might use in a day or less. This amounts to about $1.20 in gas w.r.t. global commodity
    prices.

    Global prices are defined in cost per ‘mmBTU’s, or thousand, thousand BTUs, or one million BTUs. I’m guessing you might be missing an ‘mm’ in front of your BTU number, more probably 600mmBTU or about 8% of the plant’s total annual
    energy. Anyway, forgive my assumption, as I do not have the actual first hand raw data in hand.

    Once again, thanks for getting the word out. I can imagine it a challenge to write technical articles for the mainstream which get across certain details without too much information. I don’t claim to be able to do it myself. People could
    probably hire me to cure insomnia… I would just start talking about
    all the interesting details in my engineering projects! … before you know it … zzzzzzz

    Keep up the good work,

    Kirk Jackman

    • Bob_Wallace

      Would you please elaborate on PV and CSP prices? Got numbers?

  • JamesWimberley

    Thorough and balanced piece. Well done, Tina.

  • Harry Johnson

    Storage is what makes solar thermal power so compelling. It’s possible to have 24hr on demand power requiring no natural gas startup when relatively simple thermal tanks are added. How much fuel do those slow moving cleaning trucks burn every week?
    The Fresnel system allows battery powered robot cleaners. The mirrors can also be rotated against weather damage. Wind turbines have to be located in windy regions. Solar thermal power works best in the desert regions of the world and can offer a significant segment with the renewable energy mix.

    • Aku Ankka

      Eventually those trucks, robots could very well use batteries; especially since it’s weekly cycle, just charge them the day before use. But in overall scheme of things, it probably is insignificant energy usage either way.

      • Tim

        I believe they run continuously every night but get to all mirrors weekly.

        At least that’s how I read it.

  • Freddy D

    Thanks for the great article and interesting insights into the inner mechanics of running one of these.

    The true question going forward will indeed be how this complexity can continue to compete with the relative simplicity of PV. Let alone flexibility to perform in partly cloudy environments. Regardless, all reasonable alternatives need to be prototypted, piloted, and put into production in order to find the best solutions. I, for one, would have never predicted PV prices falling so fast and as recently as several years ago, CSP looked like a good bet.

    Interesting comment of firewood. Biomass actually plays a good role in heating buildings. Firewood / pellets are 100% renewable, and the percent of the biomass performing something useful approaches 100%, whereas in liquid biofuels, 99.9% of the energy in the biomass never makes it to the wheels of the car.

    • JamesWimberley

      Agree on wood for heating. When I lived in Strasbourg, I once bought firewood at an auction, mainly attended by farmers who were heating their houses entirely with wood, buying a year’s supply of 7 cubic metres or so at a time. The snag was that you had to collect the cut logs from the middle of the Haguenau forest. This is predominantly oakwood, managed sustainably for at least 150 years and probably more. The saplings are planted densely to encourage vertical growth, and thinned twice: at around 10 years, when you get poles that used to be more useful than they are now; and 40 years, when you get 10″ logs that you split for firewood. The final cut at maturity is at 100 years, for very valuable timber.

      There is a problem with firing power stations like Drax in the UK with imported wood pellets from the SE USA. This is no longer from waste wood but whole trees. It may be sustainable in carbon terms, but damaging for other values like recreation and biodiversity.

  • partyzant

    Why they need storage in csp? Can’t they store energy in heat and just use this heat at night to generate electricity?

    • Pawan Sharma

      Yes. What happened to molten salt heat storage that was supposed to work into the night.

    • Aku Ankka

      That would be the storage: CSP does not have magical storage aspect by itself: storage comes from using transfer material that can retain heat well (like molten salt), as well as having much more of that material than what is needed for simple transfer from collectors to turbines. Further, mechanism has to be more complicated to regulate flow of that material.

      Without storage requirement other materials may be more optimal than salts, from both cost and operational/efficiency perspective.

      So basically design and optimizations are bit different with and without storage.

  • JamesWimberley

    I’ll pass up the opportunity to recite my usual piece about allowing vegetation and wildlife or livestock under solar equipment. This is a true desert with no water and no vegetation.

    • Simple INDIAN

      But that is a very good idea elsewhere to be implemented compulsorily.

  • Steven Geiger

    solid performance in the harsh desert sandstorms and high winds, and dealing with dust, pretty much negates the Glasspoint model where you need to put the mirrors inside a protected glasshouse (with the correspondingly massive hit to efficiency from row shading and glass roof).

    As far as the “overperformance”, isn’t that due the fact that they are burning gas to create additional power above and beyond the nameplate (i.e. solar) capacity? Would be worthwhile to ask them to break out “pure” solar production and the “gas-assisted” energy production to see the true performance of a large CSP plant in the ME desert conditions.

  • Steve Grinwis

    I’m very confident that the natural gas they can burn is more than 600k btu. That’s about $1.40 worth of natural gas….

    • Tim

      Maybe that’s per day? It’s for adjustment.

      Good catch!

  • Kyle Field

    Very neat! Given the required precision, those trucks should be autonomous…or even scaled down and made into robot form for each trough.

    • omar

      Or can be even a BEV

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