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Published on April 16th, 2015 | by Susan Kraemer


One Weird Trick Prevents Bird Deaths At Solar Towers

April 16th, 2015 by  

Sorry about the clickbaity title, but as it turns out, the solution to a serious problem discovered last year at Ivanpah — the first solar power tower in the US — actually has turned out to be “one weird trick.” Below is the exact problem, and how the problem was solved.

Dawn at SolarReserve Crescent Dunes Nevada

America’s second solar power tower, the 110 MW Crescent Dunes project, the first US power tower to include storage, has been undergoing final commissioning (testing) at Tonopah in Nevada, where it will supply power for Las Vegas till midnight.

So SolarReserve is putting the thousands of heliostats (mirrors) through their paces to make sure everything works.

One of the tests is of standby position. (Standby is when the heliostats are waiting to go to work making electricity by focusing on the tower receiver. During standby they are not aimed at the tower receiver, but somewhere in the air.)

How not to focus heliostats

Originally, the standby position was to create a tight circle of solar flux you can actually see above the tower.

But when the engineers focused 3,000 heliostats there on January 14th, 115 birds were killed as they flew through the concentrated solar flux at the focal point where all the reflections met.

According to the compliance report filed by Stantec with regulators as required by the BLM:

“Approximately 3,000 heliostats were staged in a position which reflected light and heat to a concentrated point above the central tower. A halo above the tower was visible from the ground (Figure 1). The heat was so intense that birds flying into the halo were immediately burned and smoke was clearly evident. Approximately 115 mortalities were noted between 11:15 AM and 3:30 PM. Appropriate agencies, including BLM, were notified of the situation around 12:27 PM when bird mortalities associated with the halo were confirmed.”

SolarReserve shut down the test and brainstormed how to solve the problem to reduce solar flux in standby position. The engineering team recalibrated the standby algorithm and the next day they put this into effect. Their new algorithm was designed so that no more than four ‘suns’ would hit any one focal point during standby.

“The difficulty is that that was a concentrated solar energy in that area above the tower,” SolarReserve CEO Kevin Smith told me this week.

“So what we did is we spread them over a several hundred meters of a  sort of ‘pancake’ shape so any one point is safe for birds — it’s 4 suns or less.”

BLM sketch of Crescent Dunes 4 sun solution

The one weird trick?

Focus no more than 4 mirrors on any one place in the air during standby. (When the focal point is the receiver – no dead birds. The potential danger is only during standby.)

“We have had zero bird fatalities since we implemented this solution in January, despite being in the standby position as well as flux on the receiver for most days since then,” he said. “This change appears to have fully corrected the problem.”

Since January’s mishap that delivered the Eureka moment for safe solar power tower development, no more dead birds at all. I did the math as of our conversation this week; a day or so short of 3 months with zero fatalities.

Solar flux — a feature or a bug?

Solar flux is how power towers work. Focusing thousands of mirrors on a receiver in a tower heats a fluid just with reflected sunshine.

Most people are familiar with solar PV, which makes electricity by science magic. But concentrated solar power (CSP) makes electricity by making steam that drives a turbine, like combustion of coal or natural gas does.

Except that instead of creating heat by removing mountains to dig up coal or fracking up groundwater to get at natural gas, CSP boils a heat transfer fluid using just reflected sunlight for clean energy.

In power tower CSP, thousands of mirrors concentrate multiple ‘suns’ on one spot; the receiver in the tower. The solar flux heats what’s in the receiver (water for Ivanpah; molten salt for Crescent Dunes) to ultimately make the steam.

The “bird-killing solar” story till now

The first power tower out of the gate in the US was Ivanpah, Google-funded and DOE-supported — in other words, just asking for trouble.

So when Ivanpah accidentally killed birds during standby heliostat positioning, the opposition jumped at the chance and exaggerated the numbers into the tens of thousands.

The actual tallied numbers got no media traction. For psychological reasons, truthiness beats truth.

But even frying 321 birds in the first 6 months on the huge desert site was upsetting enough to the Ivanpah developers, who had already fronted millions to build tortoise nurseries, and had committed to the purest form of CSP, using only sunlight and water, precisely because of its environmental friendliness. And now this.

Even though Ivanpah owners then implemented bird deterrents the same way that the aviation industry, landfills, golf courses, and sports stadiums have been doing since forever, and worked with Sandia National Laboratory and reduced its solar flux in standby, power tower solar was as good as dead — at least in the US — from what E&E News has since characterized as a PR Nightmare.

The brouhaha initially wound up derailing the Palen power tower project, which was to have been BrightSource Energy’s next project together with Abengoa (though Abengoa might try again alone.)

What is at stake? 

Dispatchable power. If we are going to switch to a civilization powered by clean energy, we need dispatchable energy that is available whenever the the grid needs it, day or night — that is cheaper than batteries at grid scale and better for the environment than natural gas peaker plants.

Currently, natural gas supplies dispatchable power — mostly to even out the “duck curve,” the steep ramp-up in load in the evening, that gets steeper the more of us put solar on our roofs supplying daytime power — and that means fracking.

Power tower solar with storage can enable night time solar that could supplant the use of natural gas for smoothing out the duck curve (which is already a factor in California, and will only increase as the rest of the US goes solar).

California needs storage to timeshift renewables

That’s why this one weird trick that has not merely reduced but now appears to have ended solar power tower avian mortality altogether is such a big deal.

Tags: , , ,

About the Author

writes at CleanTechnica, CSP-Today and Renewable Energy World.  She has also been published at Wind Energy Update, Solar Plaza, Earthtechling PV-Insider , and GreenProphet, Ecoseed, NRDC OnEarth, MatterNetwork, Celsius, EnergyNow, and Scientific American. As a former serial entrepreneur in product design, Susan brings an innovator's perspective on inventing a carbon-constrained civilization: If necessity is the mother of invention, solving climate change is the mother of all necessities! As a lover of history and sci-fi, she enjoys chronicling the strange future we are creating in these interesting times.    Follow Susan on Twitter @dotcommodity.

  • Charles_Higley

    No mention of the enormous water requirements for this plant. The water must come from regions nearby that are already short on water. This has to impact living and farming requirements in a significant manner. It’s not all hunky dory out there, particularly as the already high $135 rate will undoubtedly go up over time. Maintenance almost always costs more than they project.

    • Bob_Wallace

      You’re right, Charles. There’s no mention of the enormous water requirements because there are no enormous water requirements.

      Ivanpah is a closed loop system. The steam used to spin the turbine is captured, cooled, and reused. The plant is dry cooled. Water is not used to cool the plant.

      Ivanpah uses far less water than a nearby golf course.

      What we have here, Charles, is a FUD-failure on your part. Shame on you for attempting to spread lies.

  • mndasher

    Why is there a standby condition during the daytime? No need for the power? And no power at night. So the real solution is no solar power at all.

    • Bob_Wallace

      I’d guess there are times when there’s work going on with the system during which they need to shut it down. It’s expected that it will take about three years to do the ‘fine tuning’ needed to get the plant up to full output. That probably needs that they need to swap out a component or make some adjustments from time to time.

      This plant doesn’t have storage but the expectation is that if it can be shown that the basic approach works then future thermal solar plants would not be sending their electricity directly to the grid but storing heat and then supplying electricity when the Sun has gone home for the day and before the stronger nighttime winds show up for work.

  • DaveMan50

    So if every house had a battey storage there would not be a problem at all!

  • JvonRuhl

    Wait! Where did the discussion switch from bird kills solar to bird kills wind? I didn’t feel the bump! There should have been a warning.

  • tehInformant

    Why not just build a containment dome for where the light is reflecting. I don’t know how important the light is because I don’t understand the engineering behind this, but what if they subdue the lights effects with a tinted shield over the lighted emission.

  • Laura Cunningham

    Susan Kraemer needs to properly credit illustrations of solar flux when she takes them from websites and does not credit her source. The illustration of solar flux standby mode is from http://www.basinandrangewatch…..

    The problem is that birds may also die when they fly into solar flux during operation, and this needs to be discussed more. Operational solar flux is killing birds at the Ivanpah Solar Generating System, and no mitigation strategy has yet been found. This is an issue that needs more public transparency.

  • Bill Kotcher

    Ivanpah is the purest form of CSP, using only water and sunlight? You forget to mention that Ivanpah uses a boiler at its core, which is kept warm all night long with Natural Gas, and at that Ivanpah failed hence they applied for a permit to burn an additional 5 hours of natural gas during its operational hours, which we must add to the 1 hour of natural gas it was “designed” to use.

    It is not very honest to call Ivanpah, a pure, natural, CSP design when at its heart is a Natural Gas Boiler.

  • The plants in the US are in bird migration zones and the one in Isreal is going to be exactly in a bird migration zone over 500 million birds every year. Spain has very limited issues because they are away from migration zones. There is no technique to keep birds away (even when so called experts tell you), the only solution is to install different solar power systems e.g. enclosed trough, parabolic trough, Fresnel reflectors, dish Stirling, wind uplift or HyCon in the near future etc.

    • Bob_Wallace

      Or not focus too many of the heliostats on the same spot when parked.

      We should soon have a full year of data to determine if the one weird trick was sufficient.

  • roadapathy

    I can see the Fox News headline now, “Liberals use solar power to kill America’s Bald Eagles!”

  • ron davison

    30 year prediction probably a bit old. No back up logic for the non-linear comment. and plenty of data from the fields built since that refute this.
    In any event if the non-linear bird death argument ahs any legs, then my solutions of PV above reciever and morning evening PV reciever linear arrays would help solve this.

  • ron davison

    Hi Susan,
    always enjoy your articles, facts and context dovetailed together.

    I had written at the time of the bird death mortality stink (sorry couldn’t help it)

    That in the morning and evening when cos theta product of mirror surfaces is low heliostats could be focused on a train of railcars with PV or CPC PV concentration systems. This is the same time as when the heliostats are in standby mode typically early in the morning and late at night, possibly during bad weather also.
    This captures the lost solar flux instead of wasting yet will save the birds also.
    also allows better mirror utilization improving ROI as mirrors are large part of cost.

    Can also be used for stress testing solar panels for lifetime predictions by acelerating aging via suns greater than 1.
    This could be attempted to keep constant sun or track concentration levels for later model tuning only limiting suns below overstress levels that have no value in predictions as correlation drops.

    Wonder if anybody on the Ivanpoh team had read it and was the seed for the solution put in place.
    Mine will take time and EERE/NREL/DOE/ARPA-E money to put in place. But think it has merit.
    High concentration, mirror and lost flux utilization, may offset the lower utilization of the PV field. Putting a rail around the fiels and moving the mirrors to the east and west sides of the heliostat field doubles PV utilization at the expense of the rail. Junk railcars that role slowly can be bought at a discount and old rails and old railroad ties can be used to lower costs.
    PV age testing can be added if it has not reached profitability on its own up to the PV testing addition.
    In any event…
    The half life of this problem was concerned engineers brainstorming for 3 hours!

  • BasM

    It seems that this solar tower technology doesn’t carry any inherent improvement promise. Also shown when one makes the comparison with the old, still operating, tower projects in Spain.
    One reason may be that it is all old technology (the mirrors) including the old cumbersome steam turbine – generator combination.

    So the cost price will stay to high to compete in the future against wind + PV-solar + hydro + storage (batteries + P2G) + geothermal (once deep earth sensor technology improves, partly thanks to much faster computers, it will become important).

    • ron davison

      Yes, if every one just copies the last one and just makes it bigger.
      No if people just stop and try to be novel.

  • TSS

    Susan, you and your mother also do weird tricks @ $50 a pop.

  • DiscoHarvey

    Well. The solar pros lost a project and potentially lost a clean energy source that could have benefitted mankind because of bad press. Much in the same way that, say, nuclear power did?

    Turnabout is fair play, bitches!!

    • Bob_Wallace

      Nuclear lost because it costs too much.

      It’s not yet clear whether thermal solar will be competitive or priced off the table like nuclear.

      • DiscoHarvey

        You may be right, but the costs are due to Government interference and nothing more. Yucca mountain, NERC/FERC, Security upgrades, Fukushima hardening, etc. But I’ll still contend it lost to liberal hysteria (which, in fact, is driving the Government interference…)

        • Bob_Wallace

          You are right.

          If we could only get rid of government interference we could do away with all those things that make nuclear energy so expensive.

          We could do away with seismic studies and not worry if we’re building reactors over active earthquake faults. We could do away with containment domes and if one melts down just let the radiation disperse over surrounding neighborhoods. We could do away with backup generators in tornado, flood proof enclosures and if grid power is lot just let the sucker melt. We could do away with security guards and let people do what they wish on a whelm.

          We could just dump highly radioactive waste in your garage.

          Damn that interfering government. How dare they protect us from radiation?
          Why don’t they let us drive on both sides of the road if we want? Why do we have to stay on the right?

          Requiring that our food not be full of salmonella or botulism? Oh, the tyranny!

          How I long for the freedums of a libertarian wonderland. We should be more like Somalia!!!

          • DiscoHarvey

            Good Lord. I try to give you an intelligent comment and you treat me like a moron, beneath contempt. Screw yourself… Go live in a cave. Or better yet, READ something, and see exactly what is happening.

          • ron davison

            Bob Wallace is one of the top commentators and is normally so kind and thoughtful in his responses willing to explain just in case someone has made a wrong assumption. I never saw him get sarcastic (Brilliant!).

            If someone makes my PV panel wrong I will not die.
            If someone blows off the rules. laws, safety regulation put in place because a nuclear reactor is just a nuclear bomb on idle. with horrible thermal efficiency just so it can be fake fail safe. Good old San Onofre comes to mind, incompetent people in industry is not the governments fault.

          • DiscoHarvey

            What? A nuclear reactor is just a nuclear bomb on idle? Ridiculous. And if you think folks in the nuclear industry are incompetent, you’ve never worked in the field. They are some of the brightest we have. I’m sorry you missed that.

          • Bob_Wallace

            Obviously there’s a mix of bright and not bright. And even the bright can screw up at time. Equating a nuclear plant to a nuclear bomb is over the top, but that doesn’t mean that nuclear plants are benign and that we are wise to build them around where we live.

            Ask yourself something. You know that there are unique dangers associated with nuclear energy. Why should we pay higher than retail for new electricity and bring more dangers, even if you think them only modest, into our lives?

          • DiscoHarvey

            All technology has risks. Even with the disasters in the Ukraine and Fukushima, nuclear reactors have killed far, far fewer people than fossil plants (cancer caused from pollution). Look, if solar and wind were viable, I’d be all for them. But they’re not, and they only exist because of taxpayer subsidies (they make more money when shutdown than a nuke plant does operating). And of course, the technology won’t ever evolve unless it’s invested in, so I understand that as well. But everything has a danger. Nuclear’s risk is more than offset by its zero carbon footprint and negligible environmental impact. So we’ll agree to disagree, and go peaceably in our separate ways… Take care.

          • Bob_Wallace

            For all years up to the end of 2013 US taxpayers subsidized nuclear energy more than $185 billion. During the same timeframe wind and solar received about $25 billion combined.

            In 2013 nuclear produced 19.4% of all US electricity. Wind and solar produced 4.33%
            Nuclear has received 7.4x as much subsidy over time and yet produced only 4.5x as much electricity as wind and solar in 2013. We are currently getting 1.6x more electricity per dollar subsidy with wind and solar.

            Wind and solar receive production tax credits. They earn zero credits (subsidies) when they are shut down/not operating.

            Nuclear does not have a zero lifetime carbon footprint. Nuclear has a low lifetime carbon footprint, but not as low as the lifetime carbon footprint for wind and solar.

            You are correct, coal kills more people than nuclear. But being less evil does not equal good. There will never be a wind or solar Chernobyl or Fukushima.

            As you go your separate way see if you can discover some facts and not just parrot typical nuclear falsehoods.

          • ron davison

            It is fact.
            There is incompetence in the industry.
            I do not pretend to understand.
            But facts are facts.
            I did not say all people in the industry are incompetent.
            I will claim (without any proof) that those that do have integraty have been silenced.
            Thats why the industry is in such trouble.
            If it was run like the aviation industry where it is apparently obvious to everyone laymen included, the nuclear industry would now own the power industry.
            It does not because of it’s lack of safety implemtation and design.
            And if you don’t understand that a nuclear power plant is abomb run at idle I do not have the time to bring you up to speed. if you ask specific questions as to why and hopw I make this true statement then I will be glad to explain.

          • neroden

            UCS has a long list of the ways the AEC and NRC have attempted to silence nuclear engineers with integrity. The ones with integrity are generally aggressively anti-nuclear now.

          • neroden

            Yes, a nuclear reactor is just a nuclear bomb on idle.

            A specific sort of nuclear bomb, actually, and not the sort which fills the nuclear stockpiles of the US, Russia, and China. Much closer to the Hiroshima type, but not quite. A “fizzle bomb”, to be very specific, or a deliberate criticality accident. Still not worth it.

            There are very competent nuclear engineers out there; unfortunately, there are very incompetent managers and regulators. The Atomic Energy Commission is *infamous* for suppressing and downplaying safety problems and evidence of biological injury from nuclear weapons *and* nuclear power plants, and the Nuclear Regulatory Commission is just as bad. They’re disgraced and non-credible.

  • elliottreed

    If you kill enough birds, there will eventually be no more birds to kill.

    I spoke to an employee at Crescent Dunes. He said it wasn’t going to be operational for a year. So that’s a billion dollar investment that will sit idle for yet another year. Looks to me like a big waste of money.

    • Bob_Wallace

      Birds do deserve a break.

      We need to build a lot more wind and solar and shut down coal ASAP. Coal kills far, far more birds per gigawatt hours of power produced.

      And we should be building high speed rail. No sense in killing birds to protect unnecessary airplane travel.

  • Offgridman

    While it might seem obvious that they should have known, running O&M on this type of project or any of this size involves a vast multitude of details with many levels of involvement by many people. There may have been someone aware in the planning stages, but it didn’t get communicated to the people actually doing the settings or running the panels.
    It was a mistake that was found and corrected is the good point, yes it shouldn’t have happened in the first place, but nothing can change that now. Just a lesson for the next project of this type.
    This happens when you have to deal with the fallibility of the human species.

  • Offgridman

    When a link is included it needs to be passed, this and other details are available in the site commenting policy.

    • Clee

      Thanks. I read the policy. It doesn’t say anything about links requiring approval. Am I reading the wrong policy?

      “we let people comment by default… no need for your comment to wait for approval by a moderator!”

      • Offgridman

        I’ve just noticed that when comments from people that aren’t on regularly contain a link it takes a little while to get through moderation.
        You’re right that I don’t see anything specifically on that after rereading the policy, but at the bottom it does say that they reserve the right to adjust things as needed.
        This is an article from last week, you are answering someone from a couple of days ago, and your comment is showing, if after a slight delay.
        While not on this specific type of project, I have worked on similar sized ones as Chief Engineer/Manager. Do you understand my thought that sometimes the relevant information doesn’t get through to the right people that need to act on them, especially considering that it was a thirty year old data?

        • Clee

          Thanks. Yes, I’m not on often, and comment even less often. This time it only took an hour or two. The last time (before today) that I recall seeing my comment waiting approval, I waited a day and then gave up and stopped checking.

          Yes, I understand that sometimes the relevant information doesn’t get through to the right people on the project even when the information was brought up for the environmental impact assessment for that very project. With a hundred or so birds killed, it’s not a big deal. At least they fixed it quickly. If people had been killed then someone would probably be fired.

          • Offgridman

            Like with any power plant there are regulations that are supposed to prevent flyovers, so the people are safe.
            But if someone tries to push the boundaries with their drone?……. well they might have ended up with a home fried toy, as they say. 🙂

  • So many really interesting questions, thanks. Am speaking more to CSP people this week and will be back with answers/explanations next week.

  • TCFlood

    Just to avoid any confusion, the graphs of California renewable energy at the bottom of the article show the solar power in yellow. This is apparently total solar which currently in CA is only about 12% thermal solar and 88% PV. In the daily CAISO plots, the PV is shown as a dark yellow blob with the thermal as a thin light yellow band on top of it.

    Regarding: “Currently, natural gas supplies dispatchable power — mostly to even out the “duck curve,” the steep ramp-up in load in the evening that gets steeper the more of us put solar on our roofs supplying daytime power — and that means fracking.” In CA the large majority of the peaking power for most of the day is from natural gas, so having more rooftop solar only decreases the fracking – it doesn’t increase the need to offset the duck’s head with solar thermal to avoid an increase in NG use.

    • Bob_Wallace

      The pre- and post-duck’s belly can be lowered by facing some panels east and a larger portion west. This does cut the total amount of energy produced by the panels (10% to 20%) but it extends the solar day.

      Solar thermal with storage is one way to fill in the rest of the late afternoon/evening peak. It’s going to be interesting to see what best fills in the sunshine/wind gaps.

    • ron davison

      Yes but it should be kept in perspective.
      The duck curve is quackery (sorry couldn’t help it)
      because it was the second highest peak in clifonia pre PV era.
      As you can see PV is killing the primary afternoon peak.
      now the new reality is the “dreaded duck curve.”
      This should be understood as victory fro PV over the primary peak aka “afternoon”
      opponents when debunkinhg PV use it to shat on PV with they have to have “expensive” batteries. And hire buyable PHD to use old outdated data to claim PV and batteries are expensive, when the reality is the # can be up to a decade old and a magnitude off in error.
      CSP gets the fake save the tortoises and dead birds (2 orders of magnitude off #’s used) and costs and old way high CSP plant costs touted about as facts.

  • Going blind

    Your Light Blue color is difficult to read.

  • Glad the search for renewable energy is determined to protect the environment like this. #renewable

  • GCO

    (When the focal point is the receiver – no dead birds. The potential danger is only during standby.)

    That’s something I wasn’t aware of, thanks for clarifying this key point (IMHO it should have figured more prominently in this article).

    At any rate, I’m glad to see that this problem seems to have been nailed.

    • You are right, I should make more that more prominent. And I’ve spoken to people at both firms many times about lots of aspects of power towers – and yet only recently got that myself (!…)

      • It certainly wasn’t something I noticed in the many crappy articles that initially came out about the news.

        Either way, wonderful solution and wonderful article about it. Thanks again!

        • ron davison

          Sadly those articles where in the renewable rags not oil times.

      • Clee

        Susan, are you saying that you have talked to the BrightSource people and that they have indeed verified that birds are only killed during standby and that no birds have been killed since they changed their standby algorithm last autumn? Or is that only an untested assumption? Ivanpah has a larger set of fields than Crescent Dunes, so what might work in the smaller plants in Spain and at Crescent Dunes might not work at Ivanpah.

        I think both companies were irresponsible not to have considered the effect of high solar flux in standby mode on birds. But if this truly solves the problem, it is good news.

        • Ivanpah is more complex. When I last spoke with Ivanpah engineers it was more about greatly reducing the impact, with bird deterrent technology trials and heliostat diffusion during standby, working with Sandia.

          Last I spoke with NRG Energy, Jeff Holland simply said the final bird count was “about 27,000 off” (of the back of the napkin estimate by the opponents of 28,000 a year that was all over the media last year).

          Crescent Dunes is more of a true breakthrough. It is just not an issue any more.

          • Henry WA

            When and why is a standby mode required? Many thanks

          • They go into standby when they need to wake up the mirrors in the morning (they are asleep like computers at night) from stow (flat) position – to get them ready to generate.

            During the day they go into standby only when they need to stop generating temporarily.

            Crescent Dunes has a PPA to supply energy only from around midday (till around midnight), so say if the storage tank is full at maximum heat on a sunny morning they might need to go into standby in the AM.

          • Bob_Wallace

            Just wondering why the contract wouldn’t be written in a way to allow the facility to take the “extra” power to the market and attempt to sell it. Perhaps there’s too little to matter, but….

          • Interesting question… I have never asked about ‘open-marriage’ PPAs. Will do.

          • neroden

            Right, they don’t want to overheat the salt.

            It’s like the very common nuclear reactor problem, also an occasional problem at many fossil fuel plants — you don’t want to overheat your boiler.

            Worst case scenario, boiler explodes and dumps molten salt everywhere. Which is actually not that bad, since it’s non-toxic, unlike the nuclear stuff.

        • nealjking

          – It makes sense that there is no threat when the system is in power-collection mode: The purpose of the collection is to get that power into the grid, not to “burn holes” in the sky.
          – “irresponsible”: The deployment of any new technology involves unexpected confrontations with reality. Solar-power generation is a concept that came out of the engineering field: What do they know about birds and tortoises? At least, they are addressing the issue. In any event, the numbers of birds and bats killed by cats exceeds the number killed by alternative-energy production by a factor of many thousands.

          • “The deployment of any new technology involves unexpected confrontations with reality.” Amen.

          • ron davison

            Demand burning cats NOW

          • neroden

            Cats are an invasive species which causes ecological destruction — they should never ever be allowed outdoors.

  • nullbull

    I’m glad we’re being cautious about birds, but nearly every person jumping on that “but what about the poor BIRDS!!!” bandwagon doesn’t really care about birds. Most of them weren’t crying about birds after the Gulf Oil Spill, don’t cry about it after mountaintops are removed, or another X acres of prairie are buldozed for a Walmart. The only cared about birds because it was a way to make solar look bad.
    And now they don’t even have that. Sad.

    • Bob_Wallace

      It is likely that the “poor birds” collective is mainly some combination of anti-renewables/pro-coal/nuclear folks.

      I wish there was a way to prove it….

      • GCO

        What about we totally empathize with those persons concerns, then point them to the nice tally of avian mortality by energy source USNews put together and see if their heads go boom?
        => http://www.usnews.com/news/blogs/data-mine/2014/08/22/pecking-order-energys-toll-on-birds

        • Bob_Wallace

          The data in the US News article is clearly out of date.

          The “Solar High Estimate” was a bogus number created out of a misrepresentation and liberal use of a calculator. It’s the Ivanpah kills which were never occurring.

          Here’s what I’ve been able to pull together that seems to be ‘best sources’. Solar isn’t on the list. I’ve yet to see a bird kill attributed to solar panels.

          Based on bird kills per gigawatt hour of electricity produced.

          Wind farms kill roughly 0.27 birds per GWh.

          Nuclear plants kill about 0.6 birds per GWh. (2.2x wind)

          Fossil-fueled power stations kill about 9.4 birds per GWh. (34.8x wind)


          OK, so now we know that wind farms are not one of our birds’ big problems. And we know that closing nuclear and coal plants and replacing them with wind farms would be better for the birds. Should we stop there?

          No, we can make wind farms even safer for birds.

          In 2009 there were 12.5 bird kills per MW installed wind capacity.

          In 2012 there were 9.5 bird kills per MW installed wind capacity.

          That’s a 24% decrease. A very major improvement in bird safety. And we aren’t done yet.

          Annual bird kills 2009 and 2012


          • JamesWimberley

            Simply going higher reduces the number of potential collisions. Bigger rotors should intuitively also reduce the chance of impact per square metre of the swept area, though my math is not up to proving this. The main thing though is to avoid migration corridors like Altamont Pass.

            Any progress on bats?

          • Bob_Wallace

            I’ve not seen any data on bat deaths but I’ve seen some solutions that are apparently being used.

            Insects don’t fly once wind is above a certain level. If insects aren’t flying then bats aren’t hunting, at least in that windy area. By raising the wind speed at which turbines start turning a small amount of electricity is lost but bat deaths should be largely avoided.

            The other time bats are killed (in numbers) is during migration. For a week or so turbines in the migration route can be turned off.

          • ron davison

            Does the mortality change from day time to night time?
            Can we just light the blades up from the center outward to illuminate them?
            Bats use sonar can the tower emit a form of sonar they can hear so they avoid the area?

          • neroden

            Bigger rotors go slower, which helps a lot. Some birds could probably land on some of those really big really slow rotors and ride them around.

          • ron davison

            How many diseased and malfunctioning birds from fossil fuel poison? Maimed and harmed is also important.
            Like contrasting the audio hum harm from a wind tower to the pollution in Compton from the refinery
            no contest.

    • Urbane_Gorilla

      The headline was pretty grisly: “OMG! Flock of birds burst into flame and rain burning feathers and overcooked drumsticks on mirrors below!” ..At least that’s how it’s perceived.

    • ron davison

      sad in a good way 🙂

  • jburt56

    The Kochs are bummed right now.

    • Bob_Wallace

      They’ve made some phone calls and their various think tanks are working up a new line of attack.

      Koch Industries – We’re in the Business of Selling FUD to America

      • jburt56

        They’ll probably send out some guys in tortoise suits.

    • Heh

    • Stoli Cat

      Embalmed would be better.

      • jburt56

        Unfortunately they may only be resting like Nosferatu. Upon night the casket opens. . .

    • NormanWells

      Yeah, their taxes paid for a lot of this.

  • Marion Meads

    Why not simply put the all mirrors horizontally when on standby? That way, there would be one and only sun reflected off of them when bird passes thru the facility, why go all the trouble of making elaborate scheme that still focuses up to 4 suns?

    • Steven F

      The reason they are not all horizontal when on standy is time. The mirrors are large and do not move that fast. So in the past the mirrors were moved just enough to miss the tower. That way when clouds moved away and the sun cam power production could be resumed very quickly.

      By changing from the hailo to pancake Crescent dunes sacrificed fast response for lower bird deaths. The slower responce means some potential production and income is lost. Although it is probably not a big loss.

      • That’s very interesting Steven. I hadn’t realized the slow movement was why the standby was near the tower.

        • Laurier Lievre

          must take a lot of electricity to move all those mirrors. how much electricity is left for end users?

      • Stoli Cat

        They are also reflecting heat back into space.

        • No, solar flux isn’t heat. It heats objects in its focal point, but not air space. One reason humming birds were a lot of the Ivanpah casualties – they tend to hover in place.

          • ron davison

            Radiated heat is photonic, so your both half right!

        • ron davison

          Very good point, reflecting visible and infrared back out into space has value.
          Wonder if NREL has done the calculations of equivelent tonnes of CO2 reduction per sq kilo-meter of mirrors?
          (Al least the xx% not reflected back to earth by the CO2 reflective blanket. 🙂

          • neroden

            It’s miniscule because the CO2 reflects the heat back to earth, as you figured out.

          • ron davison

            But CO2 does not reflect 100% or 1.0 if your a fraction guy/gal…
            I need to go off and refresh what % does and does not reflect with pre-human CO2 dumping and post dumping CO2, methane, CFC’s solar panel/IC’s floride’s before commenting further…I will be back…

          • ron davison

            Since no one at NREL chimed in:~

      • Banana Rustler

        They could give all the mirrors a fast moving cover. Maybe just some cloth, one end attached to an air piston powered hoop the other end attached to the edge of the mirror. It would take less effort to move, and get power restored in seconds. Perhaps (if they are smart) the same system can even brush the mirror clean, and also air blast it every tenth operation.

        • Clever! Or i/o moving a cloth, use phase-changing glass – like those windows that can go black like transition lenses on sunglasses

      • papertiger0

        Potential production – way I heard it takes four hours of warm up time burning NG to get these beasts started.
        If your production is impaired by moving the mirrors that means it takes X + 4 hours to move from standby to operating.

        What a joke. What an utter waste

        • Bob_Wallace

          Combined cycle gas plants have no head storage so if they have been offline for a while they have to start with ambient temperature water. The turbine portion can reach full output in less than 15 minutes. It can take another 3 hours or so to bring the secondary steam portion up to speed.

          A thermal solar plant is going to maintain a lot of heat after being turned off. A thermal solar plant with storage could be at or close to operating temperature when the Sun comes over the mountain.

          Uttar waste? We’ll have to see what the cost of electricity is when the technology is more mature. First plants don’t give us the best costs, there’s a learning curve.

          And doing the comparison we need to add in the cost of climate change for burning natural gas in CCNG plants.

          • papertiger0

            Learning curve, as opposed to a bragging curve?
            How many billions of dollars drained from the tax payer does this learning curve cost.

            In real dollars please, not climate change costs or unicorn wings.

          • Bob_Wallace

            That’s a reasonable question.

            Between 1947 and 1999 nuclear received average annual subsidies of $3.50 billion. (53 x $3.50 billion = $185.6 billion) Nuclear has shown a negative learning curve. The cost of building reactors has gone up over time rather than down.

            Here’s what I find for Ivanpah subsidies –

            “The $2.2-billion Ivanpah Solar Electric Generating System is being built by Oakland-based BrightSource Energy Inc.,” the *Times* reported. “The Ivanpah plant was made possible by government-backed loans at low rates — 4 percent to 4.2 percent. BrightSource and its corporate investors will receive about $600 million in federal grants once the plant starts producing.”

            I’m not sure how to price the cost/risk to taxpayers for the loan guarantee. Probably the total subsidies are no more than $600 million. The loan guarantee was a smaller “insurance policy” and disappeared once the plant started production. Then the $600 million would start kicking in.
            Let’s be generous to those whose are suffering bunches in their bloomers and call it a million. The $3.5 billion given to the nuclear industry would cover 3,500 Ivanpahs. I would imagine that if thermal solar hasn’t shown an ability to lower its cost significantly by the time we build 10 plants we’ll quit building them.

            We’d give solar thermal a <0.3% opportunity to develop using federal funds compared to what we have given nuclear.

          • ron davison

            Always enjoy your comments chock full of knowledge.
            How many Ivanpahs do we need to kill the evening curve assuming they have storage?
            If we add molten salt to those nuclear plants not failing, on fault lines and with stellar safety records how many Ivanpahs are still needed?

          • ron davison

            How many trillions of dollars drained from the tax payer by oil by comparison?

          • kootzie

            How many trillions of dollars drained from the taxpayer do the subsidies to the long-profitable petro-industry and to the military cost ?

            How does pathetic petty whining about moving out of the last century contribute to the learning curve ?

          • papertiger0

            Tax breaks on depreciated assets are not a government subsidy.
            It’s like if a crook mugged you, took your glasses, wallet and watch, but left you your shoes, we wouldn’t say the mugger gave you some shoes.

            There are no subsidies on oil.

          • Bob_Wallace

            Tax breaks are subsidies.

          • papertiger0

            A rebuttal for the ages. The ages 3 to 7 to be precise.

            A rival of noitsnot, and uh-huh.

          • Bob_Wallace

            Then your claim would be that wind and solar are not subsidized by the federal government. And EV purchases are not subsidized.

            Wind and solar installation receive either Production Tax Credits (PTC) or Investment Tax Credits (ITC). In both cases wind farms, solar farms, and individual solar installers do not receive a check from the government, but pay less taxes.

            Purchasers of EVs receive a $7,500 federal tax credit.

            “A subsidy is a benefit given by the government to groups or individuals usually in the form of a cash payment or tax reduction. The subsidy is usually given to remove some type of burden and is often considered to be in the interest of the public.”


            Get the facts in order before you act childish….

          • neroden

            Apparently solar thermal with water storage can store the heat for hours, and molten-salt solar-thermal can store the heat for *months*.

          • GCO

            Nah, it just depends on the size of the tank. Make it large enough and water works for seasonal heat storage just as well, e.g:

        • Steven F

          “I heard it takes four hours of warm up time burning NG to get these beasts started.”

          Cressent Dunes is a molten salt solar thermal tower with storage. The only one of its type in the US. It only burned natural gas to melt the salt. Once the salt is melted it is stored in large very well insulated tanks. The plant would have to be completely off line for moths for the salt to freeze. Cressent dunes will only burn natural gas once. In normal operation it will not use any natural gas.

          Ivanpah is a boiling water solar thermal tower without any storage. They have to preheat the water once per day.. Ivanpah’s 3 units are the only ones of there type in the US. Yes it is having problems But most of the other 20 or so solar thermal power plants in the US are not having problems. Some are about 30 years old and working fine. Most are solar trough type without storage, and they don’t kill birds and produce the amount of power they were originally designed to do.

          PS: Ivanpah power output in the first quarter of 2015 is up 170% over 2014 performance. Ivanpah is working through the problems and performance will gradually improve.



          Also since Cressent ddunes observed the bird deaths, No dead birds have been found in 3 months. It appears the trick did solve the problem.


          • ron davison

            But where will Chickfilla get its next special dish from then?

          • Donald Ferguson

            Regarding salt storage at Crescent Dunes. Since salt is highly corrosive, how do they deal with that?

          • neroden

            They use special materials to contain the salts. Yes, they’re expensive. Many were developed for other applications and have been used in (surprise) molten-salt nuclear reactors.

            It turns out that the molten-salt solar application is a lot less corrosive than the *nuclear reactor* application, thanks to the lack of radioactivity, so they’ve got a pretty good handle on the corrosion problem. I would expect that they would have to be replaced occasionally though.

          • neroden

            Is there a reason Ivanpah hasn’t used storage? I’d think that storing the water in highly insulated tanks after it’s gone through the turbines would avoid the preheating costs.

        • ron davison

          Not true, a few to many assumptions.Probably heard it from the same people that say that 30,000 birds died.
          From a dead cold in the morning in winter it takes this long to warm up.
          Typically when clouds go over they will stop the pumps and production and the mirrors need to be defocused to not overtemperature the reciever absorber.
          The longer the mirrors take to get back to position is time removed from production with or without warmup time.

      • ron davison

        Steven do you know why they have to un-focus in the first place?
        system probably has not been d figured out how to optimise steam plant modularity so good efficiency can be had at lower suns.
        wear and temperature regulation without pumps working and such?

    • ron davison

      Your thread has children…
      Good questions will do that.

  • Doug Cutler

    Now you have a new problem: numerous FF trolls heads exploding.

    • lol. indeed! 😀

    • ron davison

      Strap some Piezos to their skulls and harvest away!

  • D1

    Presumably the strong light reflected off the tower during heating operation is enough to repel birds from an area where they might be harmed.

    When the light was focused away from the tower in a bright halo, the air reflected brightness obtained was not enough, hence the problem.

    The obvious solution is then to reduce the maximum possible localized radiation intensity, hence further spread out the light from the mirrors. Stop the harm by removing the source of the harm.

    The only thing difficult to explain is that such a logical, and quickly verifiable, solution was not established years ago at the early stages of testing.

    • Steven F

      5 years ago the only 3 solar towers in existence in Spain and no bird death problems were reported.

      crescent dunes and Ianpah were the first in the US and have larger solar fields and power output than any of the plants in Spain. IVanpah may have not noticed standby was causing bird deaths is because they switch in and out of standby more frequentl during te day and they don’t typically stay in standby for very long. Aditionally most of the bird deaths occured during a short period during bird migration. Crescent dunes was in start up and was in standby for most of the day when they noticed that problem.

      • ArcTanGentleman

        Hmm… so it sounds like they actually just need to turn them on more?

      • ron davison

        This suggest added operational procedures during migration periods.
        Another possibility is to put above the thermal field reciever a high temperature capable 2 or 3 cell space grade PV tower.
        Ideally it would glow and emit light that the birds would see and steer away from.
        it would also increase flux utilization in both standby and normal operation because stray flux from airosol spreading, some will be captured by PV.

      • Ike Bottema

        Keep in mind that the plants in Spain don’t reflect sunlight to a central tower, rather they collect sunlight in parabolic mirrors focused on tubes filled with molten salts. A tube runs along each mirror’s length thereby converting the sunlight into heat, the heat being circulated into a steam generator that, like Ivanpah, produces electricity. Birds wouldn’t be subjected to a single beam of light, strong enough to fry them.

        You mention bird migration. Is that the reason for bird deaths then? I’m curious as to why when operational, and all mirrors are focused to the tower, Ivanpah wouldn’t be the demise of many birds. Surely not all light hits the tower and any that misses the tower would be seen for miles. It seems to me that birds would be particularly attracted to the light when operational since the mirrors must be focused during that time.

        • Bob_Wallace

          Bird deaths (and there were far fewer than the alarmists claimed) were caused by multiple mirrors aimed at the same spot in the sky when “parked”, when the beams were not focused on the tower.

          The solution was to change the coordinates for parked position so that no more than four beams converged on the same spot in the air.

          Each mirror’s position is controlled by computer. It’s unlikely there would be much light spillage from mirrors not pointing at the tower during operation.

          In general, birds avoid bright lights. Bright light in nature = fire.

          • Ike Bottema

            OK thanks. My understanding was that birds were attracted to the bright lights so thanks for clarifying that. So basically the problem was that birds just happened to fly through a fry zone, which is now reduced to zero if parked and one when in operation if I have it right.

            One question regarding the parked mode. Is that to allow maintenance then? I would think that the parked position wouldn’t be used often unless there’s lots of maintenance required.

          • Salam Jalabati

            Would bright lights on wind turbine’s blades deter birds , from getting whacked ?

          • BasM

            May be, may be opposite.
            But the bird killing story by wind turbine blades is fake, so why spill money.

          • Bob_Wallace

            True. Except for one or two badly sited wind farms, bird kill is a non-issue.

            One of the problem sites, Altamont Pass Wind Farm, is having it’s short tower, fast spinning turbines replaced with much taller and easier to see turbines.

            I think there may be one farm which may need to have its turbines moved elsewhere due to raptor kills. But I’m not sure about that, I haven’t been keeping up.

          • BasM

            We have lots of birds around.
            Trucks & cars also kill birds. I’ve seen dead birds along the road a few times in my live

            We have several wind turbines in the neighborhood (~2MW), already ~5years. I pass one on my bicycle several times a week. Never seen a dead or wounded bird somewhere around, while I started looking for them ~2 years ago.


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