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By Lloyd McGraw on Apr 21, 2010 with 36 responses

Controversial Report: Wind Energy Causes Pollution

A new report claims that coal based power plants create more emissions than they normally would because utilities must comply with pro-wind energy policies.

The natural gas industry has produced a new report which claims that increased use of wind energy cause coal-fired power plants to “cycle” unconventionally and thereby cause an increase in the pollution levels they traditionally produce along Colorado’s Front Range.

Bentek Energy LLC, a consulting company, for the Independent Petroleum Association of Mountain States, conducted the report titled “How Less Became More: Wind, Power and Unintended Consequences in the Colorado Energy Market”.

“It’s not the wind that’s doing it; it’s what the wind energy is causing in behavior changes at the plants,” Bentek’s president Porter Bennett said.

According to the report, local ordinances in Colorado require utility companies to avail themselves of wind energy when it is available.  Compliant utilities are required to cycle coal plants on and off, most frequently at night when there tends to be more wind.  Because the coal plants are shutting down and restarting at irregular and unpredictable intervals they operate inefficiently and sustain interference with emission control equipment resulting in increased sulfer dioxide, (SO2) nitrous oxide (NO2) and carbon dioxide (CO2) emissions.

Data for the report came from evaluation of four years of emissions records from individual power plants owned by Xcel Energy Inc in Colorado. Emissions levels are reported to the federal government on an hour-by-hour basis.

Barring modifications to Colorado statutes, the report indicates that the problem may get worse in the future.  Presently, utilities companies operating in Colorado are required to furnish 20% of their energy through renewable sources.  Last Month, Gov. Bill Ritter signed a law bumping that requirement to 30% by 2020.

Natural gas power plants"cycle" on and off more efficiently than their coal counterparts.

The report recommends curbing the use of wind energy during the next one or two years to levels that match power output at existing natural gas-fired power plants — and building more natural gas plants in the long term.

According to the report, natural gas plants can ramp up and down without increasing emissions like their coal based counterparts.

The report could have a nationwide impact.  Congress is considering introducing a bill which may set standards for renewable energy sources nationally.  Accordingly, the ramifications of the report may extend far beyond Colorado’s four corners if it sways Congress to consider its findings during bill deliberations.

Furthermore, authors of the report claim that increased emissions from coal based power plants are not unique to Colorado as they found similar results in Texas.

Wind energy advocates, however, claim the report is flawed.

“The aggregate numbers are what they are,” said Michael Goggin, American Wind Energe Associan’s (AWEA) manager of transmission issues. “When you’re adding wind power, a zero-emissions resource to the grid, that power has to displace some of that other power. You’re driving off coal or natural gas. Wind is displacing fossil fuel generation and it’s a zero-emission resource.”

Bennett counters that the AWEA’s numbers are misleading.

“One of the points of our study is that you can’t look at aggregated data; you have to go down and look deeper because the aggregation masks the real reality,” Bennett said.

Emissions levels statewide declined during the subject four year period, in part, due to new emissions control equipment that Xcel added to its Comanche coal-fired power plant in Pueblo, Bennett said.

  1. By Kit P on April 21, 2010 at 9:13 pm

    If anyone is interested in

    reading the executive summary it can be found at:

     

    http://www.bentekenergy.com/fi…..100416.pdf

     

    I do not see any reason to take this study seriously. First to

    evaluate air pollution , you look at air quality. If air quality

    does not meet standards then you look at the sources. If Denver has

    air quality issues most likely all the cars they drive in Denver is

    the source.
     

    Since power plants are brought on line

    in the order of cost of generation. When the economy is strong all

    the base load coal and nuke plants are running full out. Wind and

    solar offsets SSGT generation. With demand down, PRB coal beats

    natural gas.

     

    More coal is not being burned because

    if wind, less natural gas is being burned because of wind.

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  2. By CEA on April 22, 2010 at 10:56 am

    To truly allocate the long term costs of wind versus conventional sources, perhaps we should factor in the cost of health from the dirty emissions of coal power plants. Sure coal is quite initially cheap when compared to wind (which is completely dependent on subsidies). However, what about the savings in air and water quality? We don’t initially put price tags to these conditions which happen in the long term. We need to see the whole picture when looking our energy portfolio to make sure that it is approached in a balanced manner (and with a balanced budget).
    Want to learn more about balanced energy for America? Visit http://www.consumerenergyalliance.org to get involved, discover CEA’s mission and sign up for our informative newsletter.

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  3. By Ana Cristina Merino on April 23, 2010 at 6:10 pm

    Counter-intuitive but good for further research.

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  4. By Russ Jones on April 24, 2010 at 5:56 pm

    I could not believe what I just read, astonishing even and this is taken as creditable evidence of wind power disturbing the pollution gradient of the coal fired power plants. In the most advanced country in the world with a superior distribution and networks second to none, how cant anybody automaticly switch excess power into the “grid” ?. The output from the steam exhaust towers should only be steam any way on the coal power plants. Remember Eddison wanted Teslas now universal ac mains power system banned as it was dangerous!..
    Read the article, I recommend it truely, then use Occams Razor and ask Quo Bono? latin for who benefits?

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  5. By Chris Merchant on April 24, 2010 at 6:29 pm

    Yeah, blame the clean energy for making the dirty energy a little dirtier.

    Fossil fuels to renewables: “I don’t *want* to drink so much, baby, but I wouldn’t *have* to if you weren’t such a b###c all the time.”

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  6. By HOmer Dean on April 24, 2010 at 7:54 pm

    No way dude, no it does not.

    Lou
    http://www.anonymous-vpn.tk

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  7. By carver on April 24, 2010 at 8:44 pm

    As a resident of Denver I see the “brown cloud” on a regular basis during the winter. Its cause is principally due to Denver’s unfortunate geographic location and frequent thermal inversions which traps mostly auto emissions and dust. However, I call bullshit on the idea that a non-polluting energy source will decrease the air quality. If it does it’s because the energy companies can not manage their energy sources efficiently.
    For the future, an increase in the number of electric vehicles and more efficient engines. will diminish the visible cloud that hangs over Denver whether they are burning coal or not.

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  8. By Jack on April 25, 2010 at 2:42 am

    Having worked at a coal-fired power plant and natural gas plant (albeit as a college intern), and based on my engineering experience, this study sounds very plausible.

    Electricity must be produced for the grid based on immediate demand – there is no significant system of storage in electrical grids – so a central command in each region orders power plants to scale up and down their power output based on demand. The energy output from wind sources varies a lot, and coal-fired power plants are the primary ones used for balancing the grid output when the price of electricity is low (since natural gas is more expensive), which usually happens during low demand (esp. night time, as the study mentioned).

    It’s a basic fact of engineering design that engines (i.e. power plants) perform best at the stable conditions they were designed for. Just like how a car engine has trouble running in the cold until it warms up, power plants have similar disruptions. So yes, it makes sense that forcing the variability of wind power onto the coal-fired plants would cause more disrupted time in the combustion process and environmental filtering, which leads to more pollution.

    This is not “wind power” causing the problem per se, but rather the unintended side effects of well-meaning “pro-environment” laws interfering with the proper management of the electricity grid.

    And this article’s quotes on the use of “aggregate data” are disingenuous, in my opinion. A more accurate statement of the situation would be, “The additional capacity from wind energy reduces the overall system pollution during high electricity demand, but potentially causes additional pollution by disrupting other power plants unnecessarily during periods of low demand”.

    However, I think the quoted sources provided a misleadingly black-and-white picture of ‘pure, zero-emission wind energy’ primarily because they did not expect the public to understand the nuances of the situation.

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  9. By Kit P on April 25, 2010 at 1:56 pm

    “Just like how a car engine has
    trouble running in the cold until it warms up, power plants have
    similar disruptions.”

     

    Well Jack feel free to tell me I am
    wrong if your internship was in the control room of the coal or NG
    power plant.

     

    A better analogy would be a car that
    has warmed up but is now going up and down hills. For example with a
    1000 MWe steam plant running at 800 MWe (200 MWe of rolling reserve)
    and 200 MWe of wind, if the wind dropped off the steam plant would
    increase 1000 MWe using more fuel.

     

    What your would have to show me is that
    the emission per MWh has increased and that they were causing air
    quality to deviate from being in the ‘GOOD’ category. Like carver
    suggested, power plants may not be the source of the problem.

     

    In France where nuke plants load
    follow, if load drops 1000 MWe at night, one nuke does not shutdown
    at night but 5 ramp down 200 MWe at night. If average load 1000 MWe
    for a month, then the plant would shut down for maintenance.

     

    When something happens unexpectedly,
    SCGT can start up very fast. During summer and winter when all the
    base load plants are at 100% power, SCGT provide load following.
    At that point when something happens unexpectedly, then the light go
    out.

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  10. By Ed Milner on April 26, 2010 at 8:48 pm

    As an engineer, I can buy that the coal power plants might be less efficient if they have to start and stop.  On a one power plant basis, it might be true that more emissions are given off, but if more coal power plants are taken off line, the overall level of pollution will be lower.  The conclusion to be reached from that logic is that we truly do need to move in the direction that the RPS’s mandate, so that more wind can be utilized to take more coal fired power plants off line.

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  11. By Kit P on April 26, 2010 at 9:24 pm

    “As an engineer, I can buy that the
    coal power plants might be less efficient if they have to start and
    stop.”

     

    What is your field of engineering Ed
    and where abouts do you live?

     

    Since there are no nuke plants in the
    vicinity of Denver, it is just a little preposterous to think that
    PSCO would take its lowest cost generation of line first.

     

    “to take more coal fired power plants
    off line.”

     

    Why would you want to do that?

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  12. By Kit P on April 26, 2010 at 10:12 pm

    Midwest ISO Real-Time Total Load
    indicates that load varies from 46,000 to 66,000 MWe on April 26th.

     

    http://www.midwestiso.org/page…..+%28EOR%29

     

    During the same time, wind generation
    dropped from 3000 to 1200 MWe.

    http://www.midwestiso.org/page…..Generation

     

    Here is an interesting presentation
    that show different sources of electricity in Spain.

    https://demanda.ree.es/demandaGeneracionAreasEng.html

     

    Nuclear is constant at about 6400 MWe,
    coal is nearly constant at about 1100 MWe but looks like about 200
    MWe of capacity is used fro load following.

     

    CCGT swings from 4400 t0 1100 MWe.

     

    All that talk about wind generation in
    Spain appears to be just that talk.

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  13. By paul-n on April 27, 2010 at 2:01 am

    Kit P said;

    What your would have to show me is that
    the emission per MWh has increased and that they were causing air
    quality to deviate from being in the ‘GOOD’ category.

    Kit,  we don’t have to show you this, it’s right there in the Bentek report, which is the whole basis for this discussion;

    The results of this study help explain why PSCO’s coal-fired plants located in the Denver non- 

    attainment area have experienced an increase in SO2, NOX and CO2 over the past few years.

    Now, we are not saying it is no longer “good”, and neither is Bentek, but they are saying emissions (or at least emissions intensity) has increased.

    And then you said this;

    “to take more coal fired power plants
    off line.”

    Why would you want to do that?

    Again, the answer is in the Bentek report, where it says;

    State renewable portfolio standards (RPS) mandate that wind energy be 

    considered a “must take” resource.  As such, when wind blows, generation from 

    coal and natural gas must be adjusted to accommodate wind generation.

    So they may not want to do that, and it may not make sense, but they have been told they MUST do that.

    This report really seems to be angling for more NG generation.

     

     

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  14. By Kit P on April 27, 2010 at 6:24 am

    PaulN just because Bentek, a company
    that promotes the use of natural gas, says something does not make it
    true.

     

    Where are the coal plants, what are the
    emissions, what is the pathway, and who are the receptors?

     

    As an environment engineer you should
    be answer those questions.

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  15. By cobydvdplayer on April 27, 2010 at 12:09 pm

    Well, the report does make a bit of sense, but they most likely exaggerated it.

    One question I had in mind the whole time I was reading the article, why not increase energy storage so you can have longer times that the coal plants are off, or on at a time.

    Also, over time, when wind energy production increases throughout the country and is put on a shared grid, you can offset higher demands in one area by higher production in another, also, you can coordinate better the secondary plants, so they aren’t cycling so quickly.

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  16. By paul-n on April 27, 2010 at 12:47 pm

    Kit, I’m sure the coal plants, and the state government, are indeed answering those questions.  I can’t because I don’t have access to the data – for some reason, the coal fired generators in Colorado don’t publish their emissions data.

    I’ll assume that they (bentek) did have access to some real data on NOx emissions and the like.

    As for the statement that they must use wind energy, that part is true, so there is the answer to your question as to why they would power down the coal plants.

    Coby, increasing electrical energy storage is far easier said than done. The only practical, large scale way is by the use of pumped hydro, and that is limited by geography and environmental considerations.  Other storage techniques exist, but they are so expensive that it’s cheaper to just pwoer down the coal plants.

    It would be interesting if the government took away the “must use wind first” policy.  This would then put the onus on the wind generators, to deliver power when it is wanted, and if that means they have to build their own storage, then that’s their issue.  It points to the uncomfortable reality that for wind to be a large, reliable portion of generation capacity, it needs storage, or controllable peaking plants (NG turbines) to accompany it.  This adds significantly to the real cost of wind power, something the wind industry is reluctant to acknowledge.

     

     

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  17. By russ on April 27, 2010 at 1:23 pm

    One question I had in mind the whole time I was reading the article, why not increase energy storage so you can have longer times that the coal plants are off, or on at a time.

    This assumes there is storage now that only needs expanded?

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  18. By wither on April 27, 2010 at 3:41 pm


    “As an engineer, I can buy that the

    coal power plants might be less efficient if they have to start and

    stop.

    Exactly. Counter-intuitive, perhaps, but to my knowledge, there is no peer-reviewed or corporate press literature claiming an improvement in CO2 emissions for using coal to trim wind capacity for wind conditions in the western states. If this is incorrect, please do everyone a huge favor and post a reference- there are a lot of plant engineers that would salivate over such a finding, and such an announcement would be the “belle of the ball” at any power industry conference.

    But the lack of evidence to date has not been for lack of trying.

    Xcel’s experience was echoed by a study at PRPA’s Rawhide plant (North of Fort Collins). Trimming their own wind resources (a few percent of the plant’s output) created at *least* as much CO2  as was being “displaced” by the wind farm. This is one of the cleanest running coal plants in the region with an enviable suite of optimization tools run by *very* motivated, nerdy plant performance folks with every incentive to improve heat rates and reduce emissions.

     

     

     


     

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  19. By Jack on May 1, 2010 at 2:54 am

    Kit P said:

    A better analogy would be a car that

    has warmed up but is now going up and down hills. For example with a

    1000 MWe steam plant running at 800 MWe (200 MWe of rolling reserve)

    and 200 MWe of wind, if the wind dropped off the steam plant would

    increase 1000 MWe using more fuel.


     

    Apparently my prompt reply failed to post, so I’ll try to cover most of the points again now.

    According to the main article, the plant operators are forced to “cycle coal plants on and off”. Not all of the plants are involved in load following, so if the power fluctuations are large enough, the operators will need to turn units on to cover load that they otherwise would want to leave offline. So it makes sense to compare the efficiency issues to a car engine starting up, but dramatic ramping up and down of power could also contribute to the problem.

     

    Also, it’s important to note that nuclear plants do not shut down based on grid demands. That puts regions heavily dependent on nuclear power in a totally different situation than one which has enough coal-fired plants to do load following. Coal-fired units are not as efficient as very low power outputs, so it’s a massive waste of money to lower 20 units to 10% output when you can have 6 at 75% and 14 off for the night. But if you then have a 20% drop in electricity supply because the wind fails, you have to turn on additional units because it’s too big of a change.

     

    To address a few points from later posts:

    1. There is effectively no electricity storage in the power grid. A cheap way to store renewable energy is being heavily research now, but it won’t happen any time soon.

     

    2. The power grid is cobbled together from dozens of regional systems; the infrastructure necessary for national-level redistribution of electric simply does not exist. The entire grid in Texas isn’t even compatible with the rest of the nation’s power lines. So it’s not going to be feasible to share wind energy between regions in the near future. 

     

    3. This kind of “unintended consequences” situation is fairly rampant with “green” technology. For example, ethanol production hugely spiking corn prices. Engineering issues are rarely as straight-forward as we wish they would be – everything is a balance of factors – so it’s not entirely surprising that when the variability of the wind power is large relative to the total electricity load that the disruption could outweigh the benefits of the displaced power. What if the law was reshaped to only require the use of wind power during the primary hours when the variability is small relative to the total electricity load? Electricity prices are often lowest at night, so it could even save money on all sides since wind power is more expensive.

     

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  20. By paul-n on May 1, 2010 at 12:06 pm

    Jack,

     

    You may be interested to read this report, from which I started another thread in the forums;

    http://www.bloomberg.com/apps/…..W_ckv.j5qQ

     

    At this point, not only are the other plants having to shut down, but the electricity has negative value.  Something is wrong when a subsidised power source keeps on producing a product that has negative value.

     

    Part of the problem here is that wind energy is subsidised, and often by feed in tariffs, so the wind operator gets paid the same, even if their excess production during the off peak period causes the price to go to zero.  The other problem is the mandate that wind must be used first.  So we are back to the ethanol situtation, only worse.  A wind operator can be getting paid 15c to produce, the system must buy, everyone else has to shut down, and the power for resale is worth 1c or even zero.  Subsidies to encourage production are wone thing, but a subsidy and mandate that creates gratuitous arbitrage is something else.

    What needs to happen is to remove both the feed in tariff, and the must buy requirement.  Then, during the off peak, the wind and other producers can decide for themselves if they will sell cheap or shut down. Wind should enjoy no special treatment here, except a zero-rating status for a carbon tax.  

    Faced with frequently selling the bulk of their production at the cheapest rates, the wind operators may finally concede what everyone else already knows – you need at least one of storage, peaking generation (hydro or GT) or large discretionary loads (e.g. cold storage) to make up for the variability of wind.  When viewed in that context, that every W of wind needs a complementary kW of alternative generation/storage/discretionary demand, the true cost of developing large scale wind power becomes apparent.

     

    As is so often the case with  well intended subsidies, they a push things further away from reality, and eventually it has to come back to earth, and ususally does so hard.

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  21. By Kit P on May 1, 2010 at 12:37 pm

    “According to the main article “

     

    Which is wrong Jack! I also do not
    think you know what you are talking about. I could be wrong because
    Denver is one of those places that has never been my backyard. Also
    it is one of those places I could not find an ISO that provides daily
    reports.

     

    I do know when the natural gas industry
    is blowing smoke. I used to work for one of the largest and about
    everything the said turned out to be wrong.

     

    The authors of the report are promoting
    the use of natural gas to make electricity. There is nothing wrong
    with that but there is no reason to believe natural gas marketers
    when they are talking about emissions from coal plants or or
    pollution.

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  22. By Jack on May 2, 2010 at 2:05 pm

    Kit P said:

    The authors of the report are promoting

    the use of natural gas to make electricity. There is nothing wrong

    with that but there is no reason to believe natural gas marketers

    when they are talking about emissions from coal plants or or

    pollution.


     

    According to the article, “Data for the report came from evaluation of four years of emissions records from individual power plants owned by Xcel Energy Inc in Colorado.” Checking up on that company, although they have 25 natural gas plants (5800 MW capacity), they also have 14 coal plants (8,000 MW capacity). This indicates that their largest source of electricity revenue is actually coal plants, even though they have more NG plants. Since the data is directly from those coal plants, while I may be suspicious of the spin, I must assume the data itself is reliable. They also have enough coal plants to provide an accurate sample of Colorado and non-Colorado emissions data, so I see no reason to suspect inaccurate data sampling.

     

    It would be foolish to take their report as the Absolute Truth, but it does indicate that an effectiveness review should be performed by the EPA in Colorado (using all the plants in the region) to determine if the current laws are achieving the intended goal. If they are not, then the laws should be reformed as necessary to achieve the desired benefits.

     

    Based on the available information, your aspersions seem entirely unjustified. Or were you actually suggesting that they have falsified data in an attempt to manipulate regional politics? You better have much better evidence than “this report was produced by a power company, the only people who have primary access to this data, therefore it must be fake!” if you want me to believe that

     

     

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  23. By Kit P on May 2, 2010 at 4:44 pm

    “Based on the available information,
    your aspersions seem entirely unjustified.”

     

    Jack, did you look at this available
    information?

     

    http://airnow.gov/

     

    “ EPA in Colorado (using all the
    plants in the region) to to determine if the current laws are
    achieving the intended goal.”

     

    Looks to me like the intended air
    quality goal have been achieved.

     

    For coal plants to cause air pollution
    there has to be air pollution. Jack is confusing air pollution with
    emissions. There are several factors that have to be considered.

     

    Jack you need to provide data that
    shows a coal plant running at 80% to 100% in a load following mode
    has a higher rate of emission per MWh than when running at 100% as a
    base load plant.

     

    “25 natural gas plants (5800 MW
    capacity), they also have 14 coal plants (8,000 MW capacity)”

     

    Look at the curve labeled “Hourly
    Breakdown of Total Production By Resource Type”

     

    http://www.caiso.com/green/ren…..sWatch.pdf

     

    California is different but it
    illustrates the idea. Renewable energy sources and nukes are loaded
    on the grid first. Then the lowest cost fossil is loaded. Large
    hydro and SSGT might be used for load following.

     

    So the expected situation would be that
    the 14 coal plants are running at 100% power except during
    maintenance. The 25 NG plants would be used for load following.
    Some may be CCGT used for base load in the summer and winter.

     

    In other word, to get to Jack’s
    conclusions and the conclusions in the report requires a giant leap
    of logic.

     

    “your aspersions seem entirely
    unjustified.”

     

    Heaven forbid that I suggest that a NG
    marketing group engage in marketing to promote natural gas.

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  24. By Jack on May 4, 2010 at 4:50 pm

    Kit P, Would you like me to be more specific on my points?

     

    The “intended goal” as I discussed it is the maximum reduction of energy production emissions possible within reasonable economic limits. At no point did I mention “air pollution”, which is a distinctly different measure than plant emissions. Most notably, the air pollution levels vary based on weather conditions; plant emissions vary based on the operating state of the power plant.

     

    The EPA is involved in this discussion because all the data used in this report is also sent to the EPA on an hourly basis from every power plant. This puts them in the position to analyze the complete data for Colorado and determine if better operating procedures could be implemented to further reduce emissions and reduce strain on the power plants (which leads to quicker breakdowns and increased maintenance).

     

    The links you provided say nothing relevant about my statement that the company who produced this report has a large share of coal power production both in and out of Colorado, indicating that they have both the experience and the data sources to competently provide such a report. Obviously the spin of the report should be taken with a grain of salt, but you are very clearly implying that the report has false results. Since they appear competent to produce accurate results, that means you’re also implying that they falsified the results.

    Do you see the connection there? If they have accurate data sources and there is no reason to think they made mistakes, the only way to get false results is to fake them. My previous comments were verifying that they should in fact have accurate data and be competent enough to avoid any mistakes, based on the available profile data on the company. So yes, this company has good reason to publicize the results because of their stake in energy production, but to call the results false simply because they have a stake in energy production is nothing more than slander. And any variation of the results being “misleading” or just “blowing smoke” is exactly the same as calling the results false, so don’t try to play on semantics to dodge the issue.

     

    Based on your expectation that natural gas plants will handle nearly all of the load following while the coal plants will be “running at 100% except during maintenance”, I have to believe that you’ve never been in the control room of a coal-fired power plant. My experience is in the Midwest, but based on Colorado’s energy production profile, I see no reason to expect such a reversal of load following procedures. The following article may help to illustrate for you the complications that wind power introduces to managing a power grid; it’s more than just the direct load changes, it’s the unpredictability that it adds to the load balancing that can amplify the problem:

    http://www.nrel.gov/docs/fy05o…../38061.pdf

    This is not a matter of “running at 80 to 100% in load following mode” because it’s not so trivially simple to handle the daily load variations. It’s particularly the 0-40% and 20-80% kind of ranges for individual power units (coal-fired plants generally consist of multiple units) that are the potential issue, since repeatedly reactivating a unit and doing large power ramps too often would lead to disproportionately large amounts of time when the environmental controls are disrupted. This is what we were discussing previously when trying to determine the circumstances of the issue. Excessive minor adjustments, especially during critical ramp up and ramp down hours, could also contribute to the problem.

     

    I see this report as essentially an indicator that there is a noticeably increased disruption, so it would be worthwhile for the concerned state or federal agencies to examine whether A) Plant operating procedures or B) Energy utilization requirements should be altered to minimize the disruptions. Clearly, it’s a balance between “not using coal” and “using coal as cleanly as possible”, but you can’t find the optimum balance unless you examine the situation, even if the result is to conclude that these disruptions are “acceptably small” in the big picture. 

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  25. By Kit P on May 4, 2010 at 6:51 pm

    “there is no reason to think they
    made mistakes”

     

    I have a whole list of reasons. Do you
    want me to state them again?

     

    “I have to believe that you’ve never
    been in the control room of a coal-fired power plant.”

     

    I have never said that I have. I will
    be happy to defer to Jack’s experience if he tells me he has any with coal other than as an intern.  .

     

    Jack I am asking why I should defer my
    experience to someone who claims to have been an intern at at coal
    plant. See Jack I think you are blowing more smoke that a forest
    fire.

     

    “The EPA is involved in this
    discussion because all the data used in this report is also
    sent to the EPA on an hourly basis from every power plant.
    This puts them in the position to analyze the complete data for
    Colorado and determine if better operating procedures could be
    implemented to further reduce emissions and reduce strain on the
    power plants (which leads to quicker breakdowns and increased
    maintenance).”

     

    Really! I love data. I love to
    analyze data. Can you provide a link to the EPA so I can look at
    this data?

     

    It is kind of like the link you
    provided me to NREL. I did read it. It is not very helpful. It
    might have been in 2005 using limited references the newest being
    2003.

     

    Want some current data?

     

    http://www.midwestiso.org/page…..Generation

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  26. By Jack on May 4, 2010 at 8:13 pm

    Okay, I recognize a circle-talker (code: troll) when I see one. Power plants are build on multi-decade planning cycles, and you’re complaining that the academic article I pointed you to is 5 years old? Do the physics of combustion magically change in 5 years? Do the foundational principles of engineering get reinvented every 6 months? The point you were supposed to get from that article was: “The variability of wind power introduces new complexities to management of the power grid that become increasingly important as more wind power is used – and therefore previously minor issues may scale to become significant problems as our power based shifts to renewable energy sources”. And no, your random spurts of unrelated data don’t help; at best, the 80% daily variation in output shown in that graph just highlights the source of the problem.

     


    I have a whole list of reasons [suggesting they made mistakes]. Do you
    want me to state them again?


    The only reason you have provided thus far is that a power production company producing a report on power production has a market interest in future power production, therefore they must be ‘falsifying data to manipulate politics for market advantage’? Do you not see the circular logic there?

    You have listed no factual reasons to suggest the report is inaccurate. What errors in methodology were made? What calculation mistake occurred? What assumption in the statistical analysis was invalid? None of us, you especially, are in a position to actually prove they falsified data; clearly, that is a job for professionals in the energy industry and regulatory agencies to handle… which is what I previously suggested would happen.


    Really! I love data. I love to
    analyze data. Can you provide a link to the EPA so I can look at
    this data?


    Why would you expect this data to be publicly available en masse? Further, how would you even get that impression from my statements? The EPA should get involved because: A) All the data is sent to them, so they likely have the only complete data set; and B) It’s their job. Did you not notice the whole ‘no one else has all the data’ connection there? Or the whole ‘this kind of data is extremely sensitive because it gives intimate details about the operation of every power plant’ problem? 

    If you continue in this same vein without actually providing a proper discussion, I’ll stop feeding the troll immediately.

     

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  27. By Kit P on May 4, 2010 at 10:04 pm

    Jack back!

    “I’ll stop feeding the troll immediately.”

    All I have learnded from Jack is that he may be a young engineer who has not devloped a skeptical attidude.

     

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  28. By moiety on May 5, 2010 at 3:17 am

    http://www.wind-watch.org/docu…..rt2005.pdf

     

    E.ON report might help; 90% of installed wind capacity must be backed

     

    Their dependence on the prevailing wind conditions means that wind power has a limited load factor even when technically available. It is not possible to guarantee its use for the continual cover of electricity consumption. Consequently, traditional power stations with capacities equal to 90% of the installed wind power capacity must be permanently online in order to guarantee power supply at all times.

     

    If these plants are running pernmanetly as Germany’s largest wind energy company says, then an increase in emissions can be expected.

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  29. By Kit P on May 5, 2010 at 4:38 pm

    “then an increase in emissions can be
    expected.”

     

    When ever I hear something that is
    counter intuitive I think that either there is a physical reason that
    is not obvious or the statement is wrong.

     

    “If these plants are running
    pernmanetly as Germany’s largest wind energy company says ..”

     

    It took me a while to read the report
    but Moiety I can not find where the report says that.

     

    A common mistake is confusing the
    capacity to generate electricity (MWe) and with the amount of
    electricity generated (MWh). A 1000 MWe power plant running at 100%
    capacity produces 1000 MWh of electricity.

     

    As so often happens, many put the cart
    if front of the horse as a result of fuzzy logic. First comes
    demand. Customers create demand which the generators match.

     

    Utilities are required to maintain a
    reserve margin so that demand is always met. If an electrical fault
    trips a 1000 MWe power plant or transmission line fails, reserve
    capacity is replaces the lost sources usually without the customers
    noticing.

     

    So no, reserve capacity is not running
    permanently. For every 1000 MWh produced by wind, a 1000 MWh is not
    produced by fossil sources.

     

    Now lets hitch up those horses in front
    of the cart. As demand increased passed what hydro could supply,
    utilities built coal plants. If coal was not available, they used
    oil and natural gas. Then nuke plants came around replacing oil.
    With a cheap supply of NG, NG was burned until it got very expensive.

     

    Then came mandates for renewable
    energy. Places like Texas and California with high generating cost
    from depending on NG could benefit from wind generation. This would
    be great if the wind resources was where and when people needed it.

     

    So there is no counter intuitive reason
    to think wind generation increases fossil emissions.

     

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  30. By paul-n on May 6, 2010 at 2:51 am

    Consequently, traditional power stations with capacities equal to 90% of the installed wind power capacity must be permanently online in order to guarantee power supply at all times.

    This line is actually in the executive summary.

    i interpret their meaning of “online” as being “ready to generate if required”, or, in other words, just because there is 6000MW of wind capacity, they can’t decommission any more than 600MW of other (coal) capacity without causing a supply shortage when there is no wind.

    Given that for half of the time, the 6024 MW of wind is actually producing less than 850MW (14%), this illustrates just how futile it is top rely on wind to supply any meaningful amount of baseload power

    Given that the non wind plants must now have a more irregular load curve, I expect there would be some increase in emissions per kWh generated.  You just can;t run the a coal or CCGT plant at maximum efficiency if it is cycling up and down.

    That said, i expect this increase in emissions per kWh (from gas/coal plants) would likely not be that great (<10%), and I find it hard to believe that total emissions/kWH for all sources (including wind) would actually increase over the year.

     

    Also interesting to note the large amounts of transmission lines needed for wind.  One way and another, wind is a very expensive exercise for a supply that more than half the time is producing bugger all.  If we assume their 90% number is valid, the 6024MW of wind can displace 602MW of conventional.  With a current average cost for wind of about $1500/MW, that is 1500×6024/602= $15k/kW of reliable capacity, way more expensive than anything except solar (which is about $35k/reliable kW).  Add in all the transmission lines that would not otherwise be needed and the picture is even worse.

    I can see some interesting discussions ahead as utilities start asking the wind developers to fully fund the transmission lines needed.

     

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  31. By moiety on May 6, 2010 at 3:17 am

    PaaulN I would see that line differently. The coal fired plants that I know do not fire up and down at least not over a large range and have a considerable lag time compared to a gas plant which is a plant that could be used for cycling. As happensd in Denmark I think it means that a surplus of electricity is generated i.e. that the coal plants are generating  but at the lower end of their cycle. In Denamrk this leads to the requirement to export a lot of wind power.

     

    In any case the need for large amounts of transmission infastructure if often overlooked. The number of substations required increases dramatically. This can be reduced if farms rather than one off develpoments (i.e. 10 turbines here ten more a few miles away) become the norm so the costs in infastructure in my view are lopsided due to poor planning. However as with paying for the infastructure you would think that the wiind producers would start refusing oine off developments for this reason.

     

     

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  32. By Kit P on May 6, 2010 at 5:51 am

    “in my view are lopsided due to poor
    planning.”

     

    Political mandates often do not take
    into account the time takes to build projects or the environment
    impact of those projects.

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  33. By russ on May 6, 2010 at 7:46 am

    Don’t mind the troll Jack – the rest of us like your posts.

    İ wonder what the Danes receive for excess (wind) power when exported. One might expect that the Germans get a real cheap feed in as they understand what is going on.

     

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  34. By moiety on May 6, 2010 at 9:57 am

    russ said:

    Don’t mind the troll Jack – the rest of us like your posts.

    İ wonder what the Danes receive for excess (wind) power when exported. One might expect that the Germans get a real cheap feed in as they understand what is going on.

     


    I posted this on another thread. As it happens the Danes have by far the highest prices in Europe.

     

    Denmark is the perfect example. Statistics show that its name plate
    capacity of its turbine fleet equals about 19% of its total demand but
    the actual amount of electricity delivered to the Danish grid is far
    less, say 9% for simplicity. The rest that is generated (and not lost in
    transmission) is exported to other contries that generally store it in
    hydroelectric systems. These are the storage systems. Unfortunately the
    cost of sending the electricity there is high (interconnector losses
    will lead to around 15% losses alone) as the other countries charge for
    use of the storage. Then these countries re-sell the electricity back to
    the Danish market at great cost to the Danes.

    http://www.instituteforenergyr…..enmark.pdf

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  35. By Rouhi on May 5, 2011 at 9:59 am

    Dear sirs
    please send informaion and price
    best regard

    [link]      
  36. By ajaxthegreat on March 10, 2014 at 3:51 pm

    And of course the natural gas industry would say something like that. They have a vested interest in promoting their own wares. Granted, gas is cleaner and more efficient than coal and oil. But still not as clean as renewables, especially when that gas is fracked.

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