The Gust Ceiling: How much wind is too much?

On Dec 13, the Midwest Wind Integration Study, (see article) which was required by the Minnesota legislature in 2005 to evaluate reliability and other impacts of higher levels of wind generation and carried out independently by EnerNex Corporation and WindLogics, found that the total integration cost for up to 25% wind energy delivered to all Minnesota customers is less than one-half cent ($0.0045 cents) per kWh of wind generation.  Great news, but it’s a little bit anticlimactic (as well as “anti-climatic change”) compared to the announcement on Dec 5 that Denmark plans to increase wind powerfrom 20% today to over 50% by 2025.  (All penetration rates are given as percentage of power supplied, as opposed to nameplate capacity, a measure which would make wind penetration rates seem even higher.)

That’s not to say this report is a total yawn.  First, Europe has a much more robust electric grid than the US (as the Northeast found out in 2003), and the fact that the study was sanctioned by a government body, rather than a renewable energy or environmental group gives it added weight.  Finally, by using extensive simulation, they came up with some relatively hard numbers on what it would cost to reach various levels of penetration.

 The study concludes that the total integration operating cost for up to 25%wind energy delivered to Minnesota customers is less than $4.50 per MWh of wind generation, or less than 1/2 of 1 cent per kWh.  Put another way, this is less than 10% of the average cost per kWh of wind energy.

As I alluded to before, when talking about Europe, we need to be careful when we generalize from one utility grid to another as to the costs of integration: Europe’s grid is not the same as America’s, and Colorado’s grid is not the same as Minnesota’s.  Costs for integrating wind into Colorado’s grid are likely to be higher than in Minnesota, because we are behind the rest of the country in terms of how robust and well integrated our grid is to the rest of the country.  Because of the limitations of out grid, all of the major wind farms now in Colorado or under construction have had to be scaled back.

 Nevertheless, the study is great ground for hope.  Colorado desperately needs to upgrade our transmission anyway, and the Minnesota study only takes advantage of one of the many possibile strategies that helps firm up the capacity factor of wind: geographical diversification: “the wind is always blowing somewhere.”

Other strategies not considered:

  • Time of use pricing, which can be used to shift demand to times when the wind is blowing.
  • Plug in Hybrids, which can be programmed to be charged when power is cheap, or even supply peaking capacity to the grid.
  • Energy storage, such as the Wind-to-Hydrogen project recently unveiled at NREL’s Wind Technology Center (in partnership with Xcel Energy.)  One interesting aspect of this project that did not make most of the articles on the center is that they are experimenting with directly connecting the wind turbine to the electrolyzer, without the intermediate step of a transformer which has to be used to convert the wild AC power from a wind turbine the regulated AC power used by the grid. 

In short, I see 25% as a good start, but given that wind power has already shown itself to be cheap, safe for the environment (despite claims to the contrary, wind kills far fewer birds than coal; just ask the Audobon society), and is proving much easier to integrate into the grid than skeptics imagine, we need to start thinking like Denmark, and aim for numbers much higher than 25%.  It will take creative thinking, and serious investment not only in wind farms, but also in our grid, and even behavioral changes on the part of consumers. 

The small sacrifices we will need to make in terms of our behavior to get large penetrations of wind onto the grid, such as checking our time of use meter before we start the dishwasher or dryer, are much smaller, in my mind, than the giant sacrifices we are currently making to coal fired generation in terms of the effects of pollution and global warming on ourselves and our children.  We just don’t see the current sacrifices, because we have become used to the death from a thousand cuts in the form of mercury and other pollutants, and the incremental year on year warming of our planet, lost in the noise of large local and seasonal variations.

About these ads

7 Comments

  1. Rucio said

    If I may note a couple of things …

    Nobody claims that wind kills far fewer birds than coal. Coal provides more than half of our electricity. Wind provides a fraction of a percent. Per kWh, however, wind is at least as — if not more — destructive, especially it has yet to be shown that its presence on the grid actually reduces the burning of other fuels such as coal.

    The Minnesota integration study is flawed in that it considers only hourly variations of wind infeed. And its analysis of cost is only a comparison of accepting the energy from wind rather than a dispatchable source. It does not consider the excess capacity obviously necessary when, as the study found for one year’s data — even though smoothed to hourly averages — the effective capacity of wind is below 5%.

    Response: Looks like I got someone mad. But then, people who feel the need to defend positions which contradict the facts often find themselves getting angry. It’s much easier to get angry than to admit that you are wrong.
    Here are some facts:

    1) Among the “nobodies” who claim that wind kill far fewer birds than coal per kWh are John Flicker, National Audobon Society President. He says: “When you look at a wind turbine, you can find the bird carcasses and count them. With a coal-fired power plant, you can’t count the carcasses, but it’s going to kill a lot more birds.”

    Many species of bird (not to mention mammal, fish, plant, amphibian, etc.) are currently in danger from the effects of global warming. Many more die from the effects of the pollution from coal plants.

    2) “aweo.org” does not seem to be a charitable organization. It does not seem to stand for anything, either… I’m guessing he’s hoping to get traffic from people who mistype AWEA.org.
    I searched the IRS Charitable website, GuideStar and CharityNavigator in hopes of finding out from their tax records where their funding is coming from, but could not find them. The “.org” seems to be a misnomer. I did find a chain of comments on a Renewable Energy Access story where one of the commenters claims that “Rocinante” of aweo.org works for the Nuclear industry. Makes sense to me, but I’d be happy if he would decide to tell me where his funding comes from, himself. Especially if it could be checked.

    3) His claim that “its analysis of cost is only a comparison of accepting the energy from wind rather than a dispatchable source” is simply false. Considering that was the point of the study. Likewise the capacity of wind being below 5%… you can tell he was just making that up because, if you listened to the Inside Renewable Energy for Dec 19, you would have learned that the study was based on modeled wind based on historical data… the study was not based on new data, just new analysis of old data.

    Yes, Rucio, you may note a couple of things, but on this blog, you can expect to be called on them. Anything you want to say, I’ll be happy to publish, but not without my own response. If you really think that you have a leg to stand on, please include a link to this discussion on your own website.

    Tom

  2. tomkonrad said

    At 08:42 PM 12/24/2006, Rucio wrote:
    Hi, Tom —

    Nobody funds AWEO except me. AWEO is just me. And as you probably surmised from the registration info at whois and the featured papers at AWEO, me is Eric Rosenbloom, a humble editorial freelancer in Vermont who has taken a bit of a disliking to the dishonest and predatory practices of the industrial wind industry.

    I like nuclear power even less. Much less.

    At least we agree on something.
    I admit the nuclear industry theory was too simple. And if you were actually paid for this, you’d be making more effective arguments.

    “Rocinante” is an associate who is also adamantly antinuclear.

    Now about your reply to my comment. I hardly think there was anger in my simple statements.

    Email is like that. Tone is lost. It seems I jumped to conculusions about your emotional state, perhaps because I find it difficult to understand how someone who has studied the subject could be anti-wind and sane.

    When I told my wife that I had gotten a comment from someone who does not like wind power, she asked me, “Who wouldn’t like wind power? Doesn’t he breathe?”

    I am not saying that wind power is perfect. Consumers will have to adapt our behavior in order to use it most effectively (as I said in the post.) I simply consider the sacrifices much smaller than those of the other options currently available for large scale new generation: Coal, natural gas, nuclear, solar. The most important sacrifices associated with each of those I listed are, in order: Coal:health & global warming, NG: price & global warming, Nukes:price & safety & waste storage, and Solar:price.

    If you don’t mind, I will reply here, since you appear to have already cut off discussion by the demand of a link at AWEO.org. My site is a resource, however, not a blog or news site. If you want to publish this reply, feel free.


    I was thinking of it more as a challenge. I certainly do not expect you to link to this discussion, because you prefer to create your own little world of “facts” that are too fragile to stand up to outside scrutiny. If you do take me up on it however, I will take this conversation, and include it as a post (rather than just a comment), and also include a link to aweo.org in that post.

    John Flicker is correct that burning coal kills birds. His support of wind power is based on the assumption that wind will reduce coal burning. That assumption is unsubstantiated. In fact, the evidence suggests otherwise.

    I challenge you or Mr. Flicker to show evidence of wind power reducing the use of other fuels. Where there is hydro, that is what wind will replace. Next is likely to be relatively clean-burning natural gas. Last in line is coal. And even then, the accommodation of fluctuating wind energy requires a certain extra work on the part of the rest of the grid, i.e., a lower efficiency that would cancel much, if not all, of wind’s potential benefits.

    New wind is a substitute for other new resources, including new coal.
    I have no idea what you’re talking about with replacing hydro… the amount of new hydro being built in the US is negligible, mainly because of lack of appropriate sites, and concern about fisheries, not because it is being out-competed by wind. The only reason I’ve ever heard of removing hydro power is because the dams have been silted up, or because the dam is interfering with fish spawning. Never because the electricity is “not needed” due to replacement by wind. Do you know of such a case?

    Hydro does serve as an excellent backup for wind, but not because it’s being replaced… any dam can produce a certain # of kWh based on the amount of water flow. The nice thing is that there is choice about when that power is produced, which makes it a great complement for wind.

    The large plants that provide base load aren’t even in the line.

    Not existing ones, unfortunately.

    I assumed you had read the actual study under discussion. Even in the executive summary, on page xvii, it shows very clearly that using 2005 wind data the “effective load-carrying capacity” of the wind plant at 25% penetration would be 4.1%. And remember, that is using data smoothed to hourly averages (as noted, e.g., on pages pp. 22, 41-45, and 49).

    The Effective Load Carrying Capacity ELCC of 4.1% (the worst of the three trial years) is given as a percentage of nameplate capacity. However, the wind penetration of 25% we are talking about is the percentage of power generated. Apples and oranges.

    No, I had not read the study… but neither did I dismiss its conclusions without having done more than skim the executive summary. I read two articles about it, listened to an interview with one of the lead investigators, and reviewed a Powerpoint of the main conclusions of the study.

    The cost analysis only considers how much cheaper it would have been to provide that 4.1% from a dispatchable source. As I said before, it ignores the expense of maintaining the other 95.9% excess capacity (and largely unused infrastructure).

    Again, you’re confusing nameplate capacity with the capacity that is actually needed by the system. -TK

    Yours,
    ~~
    Rucio

  3. tomkonrad said

    Rucio said…

    I challenge you or Mr. Flicker to show evidence of wind power reducing the use of other fuels.

    Have you found that evidence yet? It was noticing that the whole business is hype without actual proof of benefit that stopped my breath. Follow the fuel, not the electrons.

    I do not think that any coal plants have been decommissioned due to wind. Nor do I expect it. I only hope that less new ones will be built than would otherwise be, or, if they are built, they will not be run at full capacity.

    It seems strange to me to argue, as you seem to be doing, that if none of the currently installed wind were in use, there would be no more use of fossil fuels than we have now. Even in the worst theoretical case, that wind contributes nothing to the baseload capacity of the grid, the existence of wind allows fossil fuel plants to be used less than they would be otherwise. This is a good thing. They also contribute marginally to baseload. This is also a good thing.

    Because wind allows fossil fuel plant to be used less, it allows the necessary mix of these plants to include more natural gas, which costs more to use, but less to build. Since NG is much cleaner than coal (both in conventional pollutants and in CO2), this is a good thing.

    You seem to be arguing simply that this is way too expensive, and it is… at some high penetration of wind that has yet to be determined (and that penetration will depend on local wind conditions and the mix of other generation on the grid.) Considering that the environmental costs of coal are ignored in the US today, and the costs to the grid of intermittent wind are constantly harped on by utilities, in addition to the fact that wind represents change, while coal and natural gas are the status quo, the balance seems already tilted towards fossil fuels.

    New wind is a substitute for other new resources, including new coal.

    Did you know that Germany (most wind plant in the world) has 8 new large coal plants on the fast track?

    Sounds like they need more wind, as well as more energy efficiency programs and power management. Just as we do here.

    I have no idea what you’re talking about with replacing hydro…
    Hydro does serve as an excellent backup for wind, but not because it’s being replaced… any dam can produce a certain # of kWh based on the amount of water flow. The nice thing is that there is choice about when that power is produced, which makes it a great complement for wind.

    That’s exactly what I meant. I assumed you understood that the grid must keep a constant balance between supply and demand. That means instant switching of some source to balance the highly variable wind. Where there is hydro, that is the source that is most likely to be used. That is, where there is hydro it is hydropower being displaced, not fossil fuels.

    Yes, hydropower will be displaced in time, not shut down. The net use of fossil fuels will then decrease, given constant electricity usage and the same amount of water flowing through the dams. You seem to think this is a bad thing… I’m not sure why.

    Danish wind, e.g., is mostly shunted to Norway and Sweden to do just that.

    Yes, and it provides Norway and Sweden with cheap power, which allows them to make less use of fossil fuels. Also a good thing.

    >…ELCC…

    Easy now. Though I pointed you to a page “even” in the executive summary, I did read the whole thing. Not the publicity spin. Rounding the 5-minute data to hourly averages was the first thing I noticed.

    Effective capacity is the important number in system planning.

    Here’s where we disagree. It is AN important number… but you seem to feel that all the extra power generated when the wind is blowing to be completely worthless… that is the implication when you focus on ELCC and discount all else.

    You are effectively taking the position that the only useful capacity is capacity which is running 24/7 (which, by the way is not true even for coal or nuclear. During May 2005 to March 2006, here in Colorado, all 5 of Xcel’s coal plants experienced supply disruptions, which prevented them from running between 15% and 30% of that period, in addition to downtime due to maintenance.) This information came out in the recent rate case hearing in which I participated.

    http://tomkonrad.wordpress.com/2006/11/04/down-at-the-public-utilities-commission/

    It represents how much actual capacity they can count on from wind. As you note, it is very different from the capacity factor, which represents the output whether it is useful or not. Much of the time, the wind rises when demand is low and is low when demand is high. More wind turbines don’t improve that situation, so as more are added the effective capacity approaches zero (as a study by the Irish Grid, using 15-minute data, found).

    You can read more data about this in my paper:

    Because of the cubic relationship of power production to the wind between cut-in and rated speeds, a wind turbine produces at or above its average rate (the capacity factor) only a third of the time. Another third of the time its production is virtually nil.

    Geographic diversification helps with this. It’s well established that the capacity factor of wind farms is much lower than fossil fuels… your points are true, and already accounted for in the planning process. Unlike environmental externalities.

    Thus other capacity can not be mothballed.

    But it can be used less, and since the other capacity is fossil, this is a very good thing. And the combination of wind and hydro you explain above CAN allow other capacity to be mothballed (or better yet, not built in the first place.)

    And, so I note again, there is a cost to maintaining all that extra capacity that the Minnesota study ignored.


    Perhaps you should read pp66-68, “Reserve costs” again.

    (It also ignored the cost of new high-capacity transmission lines and substations for the wind facilities.)


    That was rightfully ignored…

    Transmission is a cost for wind, and included in the cost of any particular project. Wind typically requires more new transmission than fossil fuels, and that cost needs to be accounted for in the planning of any particular farm… just as new transmission for fossil fuels (which is often needed as well) should be accounted for in the planning for those projects.

    TK

    Yours et c.
    ~~
    Rucio

  4. tomkonrad said

    Rucio said,
    Just a couple more notes.

    It seems strange to me to argue, as you seem to be doing, that if none of the currently installed wind were in use, there …
    …snip…
    … capacity of the grid, the existence of wind allows fossil fuel plants to be used less than they would be otherwise.

    Again, I ask, where is the evidence of fossil fuels being used less because of wind? Why isn’t the most basic premise of this industry not backed up by actual data. It is not strange to go beyond theoretical potential to real-world data after systems are in place. Yet, despite decades of experience, such evidence is notably absent.

    Because wind allows fossil fuel plant to be used less, it allows the necessary mix of these plants to include more natural gas, which costs more to use, but less to build. Since NG is much cleaner than coal (both in conventional pollutants and in CO2), this is a good thing.

    So wind requires more use of natural gas (coincidentally one of GE’s other big divisions). I agree that more natural gas is better, but that expansion could be done just as well without wind.

    You seem to be arguing simply that this is way too expensive, and it is… at some high penetration of wind that has yet to …
    …snip…
    … represents change, while coal and natural gas are the status quo, the balance seems already tilted towards fossil fuels.

    If wind worked, i.e., if it really reduced fossil fuel (or nuclear) use, then I don’t care what it costs — the benefits (of sensitively sited wind facilities) would be worth it. But if a study argues that wind is cheap, then I must point out what I perceive to be a flawed analysis. If you say that it doesn’t matter what it costs, since the full costs of, e.g., coal, are not normally considered, then I must point out the flawed assumption that wind is an alternative. It is only an add-on. Thus, the full costs of coal are still there along with the full costs of wind.

    Yes, hydropower will be displaced in time, not shut down. The net use of fossil fuels will then decrease, given constant electricity usage and the same amount of water flowing through the dams. You seem to think this is a bad thing… I’m not sure why.

    The main argument for wind energy is carbon reduction. If it is displacing hydro, there is no carbon reduction.

    Danish wind, e.g., is mostly shunted to Norway and Sweden to do just that.
    Yes, and it provides Norway and Sweden with cheap power, which allows them to make less use of fossil fuels.

    No — it allows them to let the water flow through the dams but not through the turbines. That doesn’t save fossil fuels, it just reduces the electricity they generate from hydro.

    It represents how much actual capacity they can count on from wind. As you note, it is very different from the capacity …
    …snip…
    … of the time. Another third of the time its production is virtually nil.
    Geographic diversification helps with this.

    I’m afraid it doesn’t. Those thirds are seen in western Denmark’s entire grid, Eon Netz’s entire grid in Germany, and the study in Ireland of projections for the entire island.

    Thus other capacity can not be mothballed.
    But it can be used less, and since the other capacity is fossil, this is a very good thing. And the combination of wind and hydro you explain above CAN allow other capacity to be mothballed (or better yet, not built in the first place.)

    Because of what we now know about its damage to the environment, new hydro dams are rarely being built. That means only existing hydro is used to balance the wind. That means no change to the system except for using the hydro to generate electricity less. No change in fossil fuel use. No mothballing of plants, which still need to be there when the wind isn’t blowing, especially during high-demand heat waves.

    Another factor that I noted before and that is adamantly ignored by wind promoters is that where there is not sufficient hydro, then the extra switching or ramping of thermal plants to balance the variable wind lowers their efficiency, burning more fuel with more emissions.

    That is likely the reason that there is no evidence of wind reducing fossil fuel use or its emissions.

    It’s well past time to stop considering what wind might do and to examine what it has done. Which is nothing but ruin a lot of landscapes, fragment habitat, and kill birds and bats (the latter in shockingly high numbers).

    Yours et c.
    ~~
    Rucio

    This all seems to hinge on his assertion that energy produced from wind does not reduce the amount of coal or natural gas used, and that less hydro is used because of it (as opposed to my interpretaion that the hydro power is simply used at different times.) Apparently power from wind has this special characteristic that it is either wasted, or the demand it satisfies would not have been met by other sources otherwise. It’s clearly a conspiracy that the industry has not enlightened us to that fact.

    Thank you, Rucio, for opening my eyes!

  5. Rucio said

    If only. You must admit that the argument for wind is that it reduces fossil fuel use. Until that is actually shown, I must remain skeptical. Smugness is not that evidence.

  6. tomkonrad said

    Exactly: The argument for wind is that it reduces fossil fuel use.

    Electricity is fungible. No one can tell where a certain bit of power came from, except in a closed system. There are many hybrid wind-diesel systems in Alaska, for example, where this is clearly the case. But we have been talking about state and national grids, where the evidence is all indirect.

    To use one of your own examples, when Norway and Sweden buy Danish wind (I actually heard that more goes to Germany, but that’s beside the point), they pay money for that power, if only a few cents per kWh. Why would they do this, if they were receiving no benefit from that power?

  7. Rucio said

    Western Denmark is connected to Norway and Sweden. Eastern (more southern, actually) Denmark is connected to Germany. They are not connected to each other.

    Since each is in effect one big grid, the other countries are obligated to do what they can to keep the whole system stable. That means absorbing Denmark’s unusable wind energy, since they have plenty of easily switched hydro in one case and very large size in the other.

    Fuel use is well documented. It would be very easy to show a change that correlates to wind’s presence on the grid. One can readily show, e.g., that natural gas replaced oil-generated electricity in this country, or coal replaced oil in Denmark.

    Even in reports of closed systems, there is a strange failure to show the actual effect on fuel consumption, only on electricity production. It would be worth knowing — especially for people advocating wind — how much of wind’s benefit is canceled by the extra fuel burned in making the diesel generator start and stop frequently, or how much electricity generated is lost in the intermediate step of battery storage (or hydrogen or pumped hydro or compressed air). Especially with an existing system into which wind is introduced, such data would be easy to report: fuel consumption per demand before vs. fuel consumption per demand after. Yet that is never done. One has to wonder why.

RSS feed for comments on this post

Comments are closed.

Follow

Get every new post delivered to your Inbox.

Join 151 other followers

%d bloggers like this: