Clean Power

Published on May 7th, 2014 | by Michael Barnard


Wind Power Cuts CO2 Emissions On Close To 1:1 Basis

May 7th, 2014 by  

Originally published on Energy & Policy Institute.

Wind farms reduce greenhouse gas emissions in the overall electrical grid on close to a 1:1 basis. Typical grids produce 800 g of CO2 equivalent (CO2e) per KWh generated by their mixes of fossil, nuclear and renewable generation, and wind energy displaces virtually all of that. It’s difficult to imagine the mindset in which one would assert that black is white and that wind energy actually increases greenhouse gas emissions or does not reduce them. Yet many anti-wind commentary continues to make this claim based on an overlapping and baseless set of myths.

To summarize the reality of the situation:

  1. Wind turbines have very low full-lifecycle carbon emissions
  2. Wind turbines require very little backup
  3. Fossil fuel plants that provide warm standby for variances in grid electricity demand work efficiently
  4. Wind farms cause only minor micro-climate effects
  5. Wind turbines pay back their total environmental debt in months

And so, on to the underpinnings of each of the realities and their attendant myths.

1. Wind turbines have very low full lifecycle CO2e emissions 

Those opposed to wind turbines make a remarkable claim about this form of generation: that the energy and materials required to manufacture it, and the concrete required for the base during construction emit so much CO2 that wind turbines never pay the carbon debt back.

But what does a full lifecycle cost analysis of carbon from cradle-to-grave show?

Concrete use is factored into the full lifecycle cost analyses (LCA) comparing various forms of generation. Manufacturing LCAs follow ISO standards, must be published and must be subjected to external independent auditing. Every manufacturer of anything bigger than a breadbox follows the same standard, regardless of what form of generation they are building and maintaining. The best available meta-analyses of all forms of generations’ lifecycle costs of energy show that wind energy has a full-lifecycle, CO2e emission lower than any other form of generation, lower than nuclear, 1 / 50th of natural gas and 1 / 100th of coal.

Screen Shot 2014-04-16 at 8.49.48 PMAs for the amount of concrete in wind turbine bases, the best analogy is that a modern wind turbine of 2.5-3 MW in scale using straight concrete foundations uses the same amount of concrete as about 6 modern detached homes do for foundations, basement walls etc. A 250 square meter / 2,500 square foot home requires about 36 cubic meters of concrete, while a wind turbine foundation requires about 300 cubic meters. Rock-anchor systems have seen 56 cubic meters of concrete used. Let’s call it an average of 6 homes equivalent concrete per wind turbine.

Modern wind turbines are typically in the 2-3 MW range, with much larger ones offshore and larger ones often considered for most wind farms. Assuming 2.5 MW average for a modern wind turbine, this would require about 400 wind turbines to enable a gigawatt of generation capacity, resulting in about 2,400 homes equivalent, not 30,000 homes worth, as some have asserted. If you scaled up for apartments, townhomes and bungalows, you might get to 6,000 homes, but nowhere near 30,000.

So not only do wind turbines not use unusual amounts of concrete, it is included in the apples-to-apples comparisons that show that with the concrete bases, wind energy is still enormously better than fossil fuel generation alternatives.

2. Wind farms don’t require much backup and it exists already

People opposed to wind energy often claim that it requires 100% backup due to the variability of the wind, and further that this backup must be built just for this purpose and that it will often be coal generation, the dirtiest form of generation. This would be true if the following were true: wind was being expected to be the sole form of generation, the grid was small and isolated from other grids, no generation existed at all today and coal plants were actually useful as renewables backup. None of these things are actually true.

No one suggests that wind energy provide 100% of grid demand except as a thought exercise, but many agree that it makes sense in the range of 10-30% of grid demand for the majority of jurisdictions (outliers including Spain, Holland and one state in Australia).

Grid interconnectedness is one of the major themes of the late 19th and now 20th century. Buying and selling excess power across jurisdictional boundaries allows much more efficient use of generation assets, and jurisdictions such as Quebec invested in major hydro projects with the expectation of selling electricity to Ontario and the USA. Major transmission lines are being built in the USA to bring power from the plains to the coasts.

According to major grid management studies in the UK and Finland, renewables at penetrations of up to 20% of demand will require only 20% of their annual generation as backup. That backup will come from existing nearby jurisdictions, unused hydro and existing generation capacity that is no longer used full-time. Natural gas plants are typically used for peaking supply now, which is exactly the same usage model needed for renewables backup; they often have capacity factors of 10% already. This doesn’t change anything about the use of natural gas.

As demand in developed nations such as the USA and Canada is flat, not growing, wind energy and other renewables are being built as major fossil generation assets retire and are directly reducing capacity factors on existing fossil fuel generation plants. No new generation is required to provide backup, as that generation capacity already exists in often poorly utilized existing assets. As the grid decarbonizes, fossil backup will be supplanted by storage and overbuild of renewables, not lead to a new build of fossil fuel plants.

Coal plants will not be used for renewables backup because it takes hours to turn them up or down; that is why coal is used for base load power, not peak load power.

And, of course, grid management keeps hot standby generation available for the occasional eventuality that a major singular generation source such as a hydro dam or nuclear plant drops off the grid, for example due to transmission lines going down in storms.

So the backup myth is inaccurate and just gets more inaccurate the more it is embellished.

3. Wind farms have little effect on fossil fuel plant efficiency

One of the attack points of those opposed to wind energy is that having hot standby backup lowers the efficiency of the fossil fuel plants required for that purpose. As the preceding section points out, backup requirements are minimal until very high penetrations and the backup already exists, but what about when wind and solar are much larger parts of the grid?

These are the results of the “high” penetration scenario of the Sept 2013 study from the US National Renewal Energy Lab where 16.5% each of wind and solar were providing total demand. Note that when 33% of energy is provided by renewables, total carbon savings would be from 29-34% of total grid emissions and other savings would be equally significant. Total fuel costs savings for supply would be $7 billion compared to less than $35 million for increased operating costs for fossil fuel generators (note the billions vs. millions difference there). This study was based on emissions data from almost every generation facility in the USA, and reviewed by over 50 grid management and energy experts from utilities, research institutes, universities, manufacturers and generation firms across the USA.

In the UK this is equally obvious from empirical data, as a direct quote from the head of Energy Strategy for UK’s National Grid shows:

Dismissing this as one of the “flakier arguments” in the renewables debate, Smith points to a recent analysis National Grid undertook for the Scottish Parliament. It concluded that over an 18 month period, the expected emissions benefit of using wind power – that is the amount of carbon dioxide saved by using wind to produce power – was reduced by just 0.1 per cent as a result of the need to use fossil fuel power stations as backup.

So wind energy requires a fraction of its capacity as backup and that backup won’t be creating nearly as much CO2e as critics claim.

4. Wind turbines make minor changes to local micro-climates

Liming Zhou, associate professor at the State University of New York, Albany published a paper on April 29, 2012 in Nature Climate Change which found that ground temperatures directly beneath three wind farms in Texas were an average of 0.72 degrees warmer at night. This was seized upon by news outlets such as the UK Telegraph and Fox News that often dispute the science of global warming as evidence that wind farms actually cause global warming.

The diagram below is from his paper showing an enhanced view of this increase in ground temperature.

First, the facts.

  • Mr. Zhou did publish a paper which found warming under wind farms in Texas at night. This was an average of 0.72 degrees.
  • It is highly localized. There is no spread of this warming beyond the immediate vicinity of the wind farm.
  • There is no observable impact on local flora or fauna.
  • There is no connection to drought in Texas.
  • The study only looked at 2003-2011 data: “satellite data for the period of 2003–2011 over a region in west-central Texas”.

Now the hype, in which Mr. Zhou appeared fully complicit although he subsequently recanted.

  • Mr. Zhou asserted in his paper that: “Our results show a significant warming trend of up to 0.72 °C per decade.” As his data only covers 9 years, it is impossible for him to assert a warming trend per decade.
  • Mr. Zhou also says “These changes, if spatially large enough, may have noticeable impacts on local to regional weather and climate.” What he doesn’t say is that this would require wind turbines everywhere. And what he also doesn’t say is that this degree of wind energy would supplant all fossil fuel generation within a radius of about a 1000 miles with its attendant waste-heat and warming CO2 emissions. The net impact would undoubtedly be highly positive. While AGW is strongly supported by evidence, Mr. Zhou was speculating.

To his credit, at no time did Mr. Zhou say wind turbines would have a larger climatic impact. This was left to Fox News and various other news sources that should have known better, but couldn’t resist the headline.

This has become fodder for a long-running myth despite coherent rebuttals by the NRDCNPR and NASA.

Once again, when the roots of myths related to wind turbines not being a key wedge in the fight against global warming are assessed, they are found to be without merit.

5. Wind turbines pay back environmental debt in months

A variety of related myths float around wind energy as well, suggesting that CO2 emissions are just the tip of the iceberg in terms of environmental harm. However, full lifecycle analysis shows that this just isn’t the case. GE, like every other manufacturer, must abide by ISO standards when performing LCAs, and furthermore, manufacturers every single form of electricity generation technology, including wind energy, solar, nuclear, coal and gas plants. The standards also require that the LCAs be published, and every manufactured wind turbine has a published LCA. This example from GE shows the typical full-lifecycle accounting results for all aspects of a modern 2 MW wind turbine. Note that it shows 146 days for payback of energy.

In this comparison, you’ll see that the two generation technologies with the highest energy payback ratio are wind and wind with pumped-hydro storage. A high ratio is good in this case.

This is just one of the examples of cross-generational comparison that finds wind energy to be about the most benign form of utility-scale generation that has been created by mankind.


Wind farms are one of the key wedges in the fight against global warming. The myth that they aren’t is a multi-headed hydra. As can be seen, each head of the hydra is as mythical as the last. It is kept alive only on anti-wind disinformation sites and by global warming denial journalists.

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About the Author

For the past several years Michael has been analyzing and publishing reports and articles on decarbonization technologies, business models and policies. His pieces on electrical generation transformation and electrification of transportation have been published in CleanTechnica, Newsweek, Slate, Forbes, Huffington Post, Quartz, RenewEconomy, RenewablesInternational and Gizmag, as well as included in textbooks. Third-party articles on his analyses and interviews with Mike have been published in dozens of news sites globally and have reached #1 on Reddit Science. Much of his work originates on, where Mike has been a Top Writer annually since 2012. He also has published a climate-fiction novel, Guangzhou Future Tense.

  • Could windmills displace wind machines used to save crops?

    • Bob_Wallace

      Are you talking about combining crops with grinding grain? Windmills grind grain and pump water.

      If you’re talking about wind turbines, I doubt it. At least where I garden frost is most common on still nights when turbines would be less likely to blow.

      There are some small localized moisture/temp changes close to the tower. A bit of drying. Vineyards have looked at turbine effects as a way to decrease bunch rot. I haven’t heard how that has worked out.

      Besides, we’re moving to taller towers in order to increase rotor sweep and get blades up into stronger winds. Any ground effects would be diminished.

      Or are you thinking about powering them to move the air on the ground? Again, probably too high.

  • 0.9 degrees is enough to save your crops from frostbite.

    • Bob_Wallace

      Or make it too hot to grow what you were growing where you were growing.

      Or raise cattle.

      How much fun do you think it will be to chase climate to the poles?

      • I’d go for indoor farming on thorium power.

        • Bob_Wallace

          Wrong site.

          Fantasy Land is over there –

          • Oo, allergic to nuclear power while it’s cleaner than wind? Lies and Nazca are why i quit donating to Greenpeace.

          • Bob_Wallace

            On topic, meaningful input or head out the door.

  • Doug

    How did one paper by Liming Zhou get so much attention? I would need to see multiple, repeatable and fully independent studies before I’d pay too much attention to “windmill heating” – is this the only publication on that topic?

    • It got attention because it fed a certain media and ‘thought-leader’ perspective on both global warming and renewables. They thought it was at least funny, and many thought it would be a good way to discredit both AGW and wind turbines.

      There are one or two other studies which show similar effects: boundary air mixing changing very local ground temperatures in minor ways. Most agree that it’s likely a good thing for agriculture incidentally.

  • Mint

    Several of your arguments refer to developed countries: Flat demand, existing generation capacity, and interconnectedness.

    Wind loses a lot of attractiveness in developing nations. There, you have growing demand, so it can’t be met with just wind. It has to be, for example, 1GW wind + 450 MW FF, or just 500MW FF. The latter is far cheaper to build, and many such countries don’t have cheap natural gas resources anyway, so will just opt for coal.

    Wind is a partial solution, and won’t save us from AGW until we figure out ultra cheap storage.

    • Bob_Wallace

      Have you checked the cost of building a new coal plant?

      Are you aware that the World Bank and several investment banks will no longer finance coal plant construction?

      Why would a developing nation want to saddle themselves with decades of coal purchases when they can install and operate renewables for far less?

      • Mint

        I have, and I can only say to you that coal is not nearly as expensive outside the west. It’s only expensive when you add all the emissions control systems. Why would it be twice the cost of CCGT when it’s really just half of such a plant with heat provided by coal instead of turbine exhaust?

        I challenge you to explain how coal construction price could suddenly become so expensive for non-emissions reasons.

        Yes, I am aware about the World Bank, as you have pointed it out many times to me, but it’s irrelevant because capital shuffles around (wherever the World Bank lends, it allows private money to be used elsewhere), and it’s only ~$25B of lending per year anyway.

        You CANNOT install and operate renewables in isolation for far less. Mike Barnard rightfully points out that existing FF is what eliminates the need for new backup, and he also points out that natural gas backs up wind. Developing countries don’t have existing FF, and many don’t have cheap natural gas.

        How can you claim 1GW wind + 450MW FF is cheaper than 500MW FF? Or that we can make enough storage to negate backup construction?

        Coal use is going to increase for a while:

        • Bob_Wallace

          Mint, you seem to not have brought a price for new coal plants into the discussion. Does that mean that you don’t have one or you found one and you don’t want to share?

          Now, can you please give us a list of developing countries (outside of China) that are building coal generation and in what amount?

          This big increase in coal use – where? What offsets the drop in coal use even in the US alone? What offsets the drop that is happening in Germany and Australia? What offsets the Chinese rollback starting in three years?

          • Mint

            I gave you two independent analyses of coal projections. One is from the IEA, the other from BP. Why should I believe your handwaving claims over them?

            This is from a link I gave you:

            the World Resources Institute estimates that there are almost 1,200 big new coal plants in 59 countries proposed for construction.

            450 in India, 360 in China, about 70 in SE Asia, 25 in Africa…

            There is no drop in coal use in the US yet, as the dip in 2011 proved to be temporary:

            Yeah, there are predictions of plant closure, but they’re probably old plants whose generation was picked up by others increasing output.

            German coal use is at its highest in over 2 decades:

            Chinese rollbacks? Please. All they’re doing is promising to slow down growth. Any reductions in one area (e.g. Beijing) are more than compensated by increases elsewhere within China.

          • Bob_Wallace

            Let’s start with German coal use at its highest in over 2 decades…

            Your link makes that statement. It references a Bloomberg article which says…

            “Germany will this year start up more coal-fired power stations than at any time in the past 20 years as the country advances a plan to exit nuclear energy by 2022.”


            So your source is bull. It distorts its source and what it reports is clearly badly incorrect.

            And furthermore, the Bloomberg article is lacking all the facts.

            Germany’s new coal burning plants are replacing (not adding to) the older plants that either have been or will soon be decommissioned. These new plants were planned and construction was started prior to the decision to close nuclear plants.

            The initial plan was that by 2020, 18.5 gigawatts of coal power capacity will be decommissioned, whereas only 11.3 gigawatts would be newly installed. Due to the success of renewables it appears that the 11.3 gigawatt number will be lowered.

            Furthermore those plants will be more efficient, releasing less CO2 per unit electricity produced than are the ones they are replacing. And the new coal plants are partially load-following.

            As of November 2013 some 28 power plants with a collective capacity of 7,000 MW – roughly equivalent to the capacity shut down in Chancellor Merkel’s sudden nuclear phase out in March 2011 – have been submitted for decommissioning. This would be an 8% decrease in Germany’s coal burning capacity.

            Some will be permanently closed and a few ‘mothballed’ in case they might be needed in the future.


          • Bob_Wallace

            Now, China.

            Feel free to read China’s plans. You’ll note that they have a binding target for a “16% reduction from 2010 levels by 2015”.

            And –

            “China has a target to reduce coal consumption as a percentage of primary energy to below 65% by 2017.”


            You perhaps wish to declare that you don’t believe China will do so, as is your right. However one might want to consider that China has set a series of ‘five year’ wind targets, met each one early, and then set a new higher target.

          • Bob_Wallace

            Finally, the EIA prediction branch.

            Not worth a tinker’s damn.



            And some cleanup…

            The US is closing 200 coal plants before 2020. The fact that coal use has not dipped “yet” – so what?

            How do you burn coal when you have significantly fewer plants?

            All those planned coal plants? I’ll share this…

            January, 2011

            “Coal is a dead man walkin’,” says Kevin Parker, global head of asset management and a member of the executive committee at Deutsche Bank. “Banks won’t finance them. Insurance companies won’t insure them. The EPA is coming after them. . . . And the economics to make it clean don’t work.”

            In 2002, there were plans to install 36,000 megawatts of new coal-fired power by 2007. Only one-eighth of that was completed.

            Deutsche Bank predicts coal’s share of electric power generation will tumble further, from 47 percent in 2009 to 34 percent in 2020 and 22 percent in 2030.

            It put it this way in its report: “Based on today’s energy fundamentals, the rational economic decision is to shutter inefficient coal plants and replace them with natural gas combined-cycle power plants.”


          • Mint

            I don’t know why you focused on Germany, as that was the least important part of my post. But that chart looks pretty flat to me for Germany, and as I showed with EIA data, US has been flat for 2+ years, despite your chart suggesting otherwise due to the recession.

            “Another reason is that new brown coal plants, with a capacity of 2,743 megawatts, came on line in 2012, far exceeding the 1,321 megawatts from old plants shut down that year.”

            You can say Germany is going to change course and close more than it opens, but I’ll believe it when I see it, especially with renewable subsidies being cut and nuclear being shut down.

            Anyway, I addressed all your other requests: coal price elsewhere, plants being built and where, the supposed Chinese “rollback”…

          • Bob_Wallace

            Why did I start with Germany?

            Because I was laughing out loud by the time I got through your claim that “German coal use is at its highest in over 2 decades”.

            Germany consumed more coal in 2007 than in 2013. And more in 2006. And more in 2005. And more in 2004. And….


            Did you not even look to see that your link was a pile of ….?

          • Mint

            I didn’t ask why started with Germany. I asked why you focused solely on it, and ignored the rest.

            Your EIA data ends in 2012, not 2013, after 3 years of rising consumption. Why am I to assume that multiple news reports of higher consumption in 2013 is a lie?

            After further searching, it seems the record is for brown coal (but black coal is still at a 5 year high). I found this source link from the image you posted above:
            “Power from hard coal has reached a level not seen since 2008, while electricity from brown coal has now reached a level not seen since 1990 – the first year in which statistics for a reunified Germany could be taken.”

            So sue me. Even though I messed up that claim, German coal use has still increased every year since 2009, and they still have a bunch of nuclear to retire within 8 years. I’ll believe reduction when I see it.

            Anyway, because I carelessly forgot to put the word “brown” in there about the German coal record, the rest of the post is invalidated?

          • Bob_Wallace

            I dealt with all your stuff. I started with Germany.

            Can you read a graph? If so, look at the coal per capita graph I posted. The only way for German coal consumption in 2013 to jump to 1993 levels would be for a massive population increase from 2012 to 2013.

            You posted links to crap. What you and others haven’t understood is that the amount of electricity produced by coal increased in Germany. Germany increased electricity output by bringing new supercritical plants on line, plants which produce significantly more electricity from the same amount of coal that the previous plants produced.

            Did you not read what I posted about replacement plants?

            Did you not read this from the RI article you linked?

            “…the amount of brown coal used in the power sector (90 percent of total consumption) actually dropped in 2013 by 1.6 percent, though consumption of hard coal in the power sector was up by 6.7 percent last year. ”

            100 pounds of coal. 90 brown, 10 hard.

            Brown down 1.6% = 88.6 pounds
            Hard up 6.7% = 10.7 pounds
            Total coal consumed = 99.3 pounds.

          • Mint

            The only way for German coal consumption in 2013 to jump to 1993 levels

            FFS. Do you even read my posts? I already said I WAS WRONG. The 20 year record was for brown coal generation, not total coal. The latter is only a 5-year record. I’m sorry. Mea culpa. My bad. Can we please get past that already and discuss the rest?

            I did read the RI link, and you obviously did not.

            You’re not reading that sentence right. “90% of total consumption” doesn’t mean “90 brown, 10 hard”. It means 10% non-electricity for brown coal. Look at the spreadsheet link in the same article. 162 TWh brown coal (up from 161), 124 TWH hard coal (up from 116). Brown coal consumption dropped slightly due to efficiency, but it was more than compensated by the rise in hard coal consumption. I’ll bet you anything that your EIA link will show increased coal use for 2013.

            Your graph shows roughly flat coal consumption per capita for 20 years and slightly increasing in the last 5 years. I don’t see what your point is.

            I dealt with all your stuff. I started with Germany.

            No you didn’t.

            You asked for coal construction cost outside the west, and I gave it to you for India at ~$1/W (and they only pay ~$30/tonne for coal, which renewables can’t touch). Here it is for China and Korea:
            Well under $1/W for supercritical coal. In the west, emissions control triples the price. The delta for renewables is, unsurprisingly, far smaller.

            You asked for new plants worldwide, and I showed you growth in China, India, SE Asia, and Africa. I showed you two independent projections of future growth without a peak.

            You mentioned “Chinese rollback”, which is a crock. Here’s Greenpeace’s report, which looks all rosy about reduction until you see the actual projection on page 5:

            Better than previously expected, but reductions are far from sight.

            Germany’s coal use being a 5-year record instead of 20-year is so insignificant compared to all these factors.

            Coal is here for a LONG time.

          • Bob_Wallace

            China says it will cut coal use.

            The US says it will close 200 coal plants.

            You choose not to believe. That’s your right. Time will tell.

        • eveee

          What is the point of coal in transmission infrastructure poor India? Its pointless to point out what coal could or could not do when India’s grid is the issue. There, renewables like distributed solar do better. In China, its not the same, there is a grid, but even there the grid has to expand. It is not easy to make sweeping generalizations on the issue of emerging nations and demand. There is considerable differentiation. Lets also not conflate wind integration in developed countries with wind and solar in emerging countries.

          Right now the whole game on coal is China. India demand balances US and EU decline. India does not appear to be growing as fast in coal consumption for various reasons, including transmission.

          In 2012, coal demand grew 170Mt globally. Chinas growth accounted for165Mt of that.

          Emerging nations are not the coal problem. China has a grid. Therefore, the issue is moot over emerging nations. Wind and solar lower coal use and CO2 in China where it matters arguments to the contrary notwithstanding. And China is doing exactly that. The problem is not that China is not investing in renewables. The problem is that China is growing fast and adding more coal, not just renewables. Growth has to slow, coal use has to decline, and renewables have to grow. As large as China is, there has to be a limit somewhere. Right now Chinas skies are a sewer. Its water is a mess. There is very little water left for thermal PP and human habitation. If this is not a limit, nothing ever will be.

  • jeffhre

    Thank you Mike. This is a terrific resource to have all of the information in one place, succinctly written.

  • owen m

    In Ireland, 1MW of conventional plant was built for every 1MW of wind. I have done the calculations from 2006 to 2013. I downloaded the official reports and took out my calculator to establish FACT not OPINION which this article is.

    • Bob_Wallace

      First, we attempt to be civilized here. Therefore we don’t shout at each other, so no more allcaps please.

      Second, it could well be the case that Ireland added gas plants as it added wind. Ireland may not have had the grid flexibility to incorporate wind without adding fill-in power at the same time. Remember, gas plants don’t “spin” during windy periods. They stay off for hours/days and then are ramped up as utility managers see a drop in wind output ahead.

      While Ireland has been adding wind and gas generation, Ireland has also been reducing coal use. Ireland is on the road to a cleaner grid, less “always on” coal replaced with clean wind and some gas to fill the gaps.

      • Bob_Wallace

        Now that you’ve calculated the total capacity (ability to generate) for 2006 through 2013 you might want to go back and calculate the percentage of electricity coming from each source.

        The critical question is whether Ireland is using the same, less or more fossil fuel for electricity.

        Capacity isn’t a good metric. That just tells you how much could be produced, not how much was produced.

        • A Real Libertarian

          I’m guessing by “spinning reserve” he means “natural gas”.

          And by “1MW of conventional plant was built for every 1MW of wind. I have done the calculations from 2006 to 2013” he means “roughly the same amount of wind and fossil has been brought online”.

          • Bob_Wallace

            That’s my take. But installing a MW of CCNG does not mean that it’s run all the time. That is it constantly “spinning”.

            We need spinning reserve for large thermal plants (coal and nuclear) because they can go off line without warning. Not so for wind and solar, it’s easy to look ahead a few hours and determine resource supply.

          • A Real Libertarian

            I mean there was a lot more fossil installed in the beginning, but afterwards renewables started growing.

            So the timeline doesn’t fit.

          • owen m

            Incorrect. You have to go to the source – Eirgrid’s Adequacy Reports. Basic logic/instinct doesnt always work where energy is involved – see jervons paradox. I spent 4-5 weeks doing an analysis on their reports with an assumption that small amount of back-up needed for wind. Results astounded me.

          • owen m

            sorry jevons paradox

          • owen m

            basic economics – if its not spinning it closes down. gas plant operators dont get paid. so your argument makes no sense.

            plants that have been shut down have been replaced. net increase. Tarbert heavy fuel oil was due to close down last year but was kept open. in utopia the article here makes sense. unfortunately……

          • Bob_Wallace

            basic economics – wind does not require large amounts of spinning reserve. That means less is spent on gas purchases. Electricity becomes cheaper. Economies thrive.

            As gas plants are used less their price per kWh will rise a bit, but most of their costs are fuel and not fixed operating expenses.

            As gas plants increase their selling price storage will step in and replace them.

          • eveee

            The fallacy is in the leap from “1MW of conventional plant was built for every 1MW of wind” to 1MW of reserves required for every 1MW of wind” to ‘wind requires reserves that conventional does not.’ The first may have been observed. The other two do not follow logically. Its the unwritten implied assertions that are the worst. Then the question becomes how much reserves? And the answer is very modest amounts up to medium levels of wind integration. Some of it depends on how much Ireland is connected to other UK grids. Ireland is small, so not much dispersal to lower variation. The studies have been done for UK, Ireland, EU, US…

          • owen m

            This implies that there was a shortage of dispatchable plant in 2006. During our construction boom. Interesting, but I dont remember any blackouts back then, although maybe they got lucky.

          • Bob_Wallace

            Can you link to a source that lists sources of electricity per year in Ireland?

        • owen m

          Dispatchable plant operators dont get paid if they dont get on the grid so they go out of business. TSOs wont accept connection agreements for plant not required. Plants arent built to sit idle. The new plant are producing power – it is very hard to get figures of exact amounts – but the 3000MW plus reserve is running in the background at a certain level. This destroys the myth that wind saves fossil fuel.

          • Bob_Wallace

            In 2011 natural gas plants had a CF of 24.2%. In 2012 their CF was 28.8%. That means that NG plants were sitting idle over 70% of the time.

            When you consider the fact that many NG plants are combined cycle and are run as ‘baseline’ generation that means that gas peakers must sit idle well over 90% of the time. In fact, we know that some peakers run only a few hours a year.

            The cost is built into the system.

            Most of the “background running” is required for large thermal plants which can go offline suddenly and without warning. Wind is much more predictable and with multiple wind farms on the grid the ramp up/down is more orderly than having a large thermal plant abruptly cease production.

      • Ronald Brakels

        As every Australian knows, but apparently not every Irish person, Ireland has had a large build out of natural gas capacity and a large build out of wind capacity due to the elimination of peat burning for electricity generation, which used to supply well over a third of Ireland’s electricity generation but which now has almost been eliminated.

      • owen m

        you can reduce coal use without the help of wind. expanding generation capacity during a period of falling demand and increased wind penetration makes no sense until you look at the reasons why. conventional plant is breaking down a lot more due to the cycling with wind so you need more back up for conventional plant

        • Bob_Wallace

          Well, first one would have to show that coal plants are cycling more. And cycling enough to damage them.

          If that is the case, if you bring that data, then the result is that they will be replace with gas plants designed for frequent cycling.

        • eveee

          Vague. How much more? NREL studies and others show the cost of extra maintenance is minimal compared to the value of the fuel saved. I already referenced some. Read a few. I suggest Western Wind and Solar Integration study. It refutes your claims. How do you reduce coal use without the help of renewables in Ireland? Less words, more citations, please. For something more trenchant,

          As long as you are going to disagree with the CT article and its many cited sources…

    • eveee

      Show a reference. I did. It contradicted your opinion. Its not my opinion that counts. Its the reference. You stated an unreferenced opinion. Back it up. Otherwise you are stating opinions, not fact.

    • eveee

      Did you make certain the conventional plants were built as reserves for wind or did you just notice they happened to be built? There is logical leap there. And what about the reserves for the conventional plants added? If so, why didn’t you cite your calculations and the official report?

  • JamesWimberley

    Good stuff, Mike. I enjoyed the point that renewables lower the spinning reserve. Wind and solar are both more reliable than fossil or nuclear by the law of large numbers, and highly predictable with the right forecasting and management software. (Reliability here refers to the risk of a significant unplanned outage.)

    Agreed that backup is not an issue until a country has much higher renewables penetration than the USA has now. Denmark copes very well with 50% wind, using Norwegian hydro as backup. But it is an issue with getting-on-for-100% renewables scenarios, and has to be planned for. The technical horizon for the USA is ten years ahead, beyond 2025. The trouble is the economics. It’s striking that <5% renewable electricity has got the US utilities in a panic already over stranded fossil assets.

    The future model will be dominated by cheap wind and solar, with joint nameplate capacity well over peak demand. However there will also have to be a good margin of despatchable backup (generation or storage), and this will be much more expensive, as rarely called on. The technical solution is a capacity market, with prices reflected transparently in grid access charges on consumers.

    BTW, don't forget geothermal in the despatchable list. Its reliability is near-perfect: developers stop at 95% rather than the technically feasible 99% simply on grounds of higher preventative maintenance costs. EGS is not a sure thing, but it's a reasonable bet that it will be available in many areas and at an affordable price by 2025. The typical size of a plant is 50-100mw, so there won't be the lumpy outage risks of nuclear and coal.

    • Actually, one of the big backups for wind energy will be wind energy based on what I’ve been learning this week at Windpower 2014.

      Slightly sub-optimizing a turbine, to 98% of potential output, allows you to get ancillary benefits of voltage and frequency stabilization out of the wind farm. Overbuilding by 20% allows you to drop output more and have the fastest reserve that exists outside of batteries at a cheaper price.

      Building out the grid connections that are in plan and underway allows regional backup with renewables.

      The updated DOE Vision presented this week here calls for 35% wind by 2050, and ask with all forms of generation except for nuclear, that means there will be overcapacity which provides opportunities for interesting grid management techniques.

      Combined with similar penetrations of solar, the need for expensive, single purpose backup like batteries drops substantially.

      • jeffhre

        Than you! I have been wondering when this would finally be confirmed

    • owen m

      Not in Ireland – spinning reserve has increased by 1MW with every 1MW of wind.

      • Bob_Wallace

        “Spinable” reserve has been added.

        Coal use has been reduced.

      • eveee

        False. See the MIT Ireland study. Graph on page 35. It shows the change in reserves needed for 1GW wind is quite small. Very little has to change in existing reserves. Other generation requires reserves as well. Its a myth that wind requires more reserves than other sources. Usually propagated by those that do not understand the power system and do not understand that a large central power station requires a lot of reserves for unplanned outages.

        If you want to prove otherwise, please show a reference. Otherwise, quit posting false opinion.

        • owen m

          i go to that page and it says “**Non-Grid study information
          so useless. go straight to the source – Eirgrid and download their reports and do your own analysis. this is not about forecast reserve this is about actual reserve. 1MW for 1MW when demand fell. crazy. wind energy is a big scam but only a couple of smart people in a million can spot it like inflation

          • eveee

            No. Non grid study is not useless. Still no reference for your assertion. The UK study and NREL study show reserves are small at penetrations up to 30%. Show your numbers and your math. Meanwhile, more references on wind reserve requirements. Non power professionals seldom know that reserve requirements for conventional plants are quite high. That is one reason wind reserve requirements are modest. Further, demand variation is a large part of the reason for reserve requirements. Reserves always have to be planned for both the demand and the composite of all the generation sources.

            page 5 of the the NREL document that quotes the All Island Grid Study,

            “While the variable generation requires additional spinning reserve, the largest contributing factor remains the loss of the largest conventional unit.” In other words, smaller distributed sources contribute to lowering reserves. Larger centralized ones increase reserve requirement.


            When you consider that a large central power plant requires 1GW of reserve for every 1GW of generation…. for unplanned outages….

            Case in point,

            “Currently, the grid’s back-up system plans for a major loss of up to 1,320MW a few times a year. But the two new reactors planned by EDF will have 1,600GW of capacity each, meaning the grid will have to increase its back-up to 1,800MW. Nuclear power stations can shut down at short notice owing to engineering problems or even a swarm of jellyfish blocking cooling water pipes, as happened in June 2011 at EDF’s reactor at Torness in Scotland.”


            Your concern for reserve requirements seems misplaced and rooted in a lack of understanding of the power system and reserve requirements. One could only be concerned about wind reserve requirements on this 1:1 basis (although false) if one were of the misimpression that conventional sources did not bear a high degree of need for reserves.

          • owen m

            Yes I know what you’re saying but it implies that Irish grid was short in reserves in 06. Unlikely as we had construction boom at that time.

          • eveee

            Im sorry. You just made an unsupported assertion and I asked for reference. I provided reference from peer reviewed papers that wind requires very little additional reserves. Now we have a reply with your opinion. If you are just going to post your opinions without references, then I am not interested.


            The additional cost of operating reserve is relatively small and likely to be to less than €0.20/MWh in 2010 if there is 1300MW of wind or €0.50/MWh with 1950MW.

            the total capacity of conventional plant that is scheduled is less than in the no wind and fuel saver cases;

            the total system generation required (from conventional and renewable generators) is lower than in the no wind and fuel saver cases

            the total fuel burn is substantially lower than in the no wind case and also less than in the fuel saver cases;

            carbon dioxide (CO2) emissions are substantially lower than in the no wind case. In comparison with the fuel saver cases however, savings are less clear-cut, due to a different mix of plant under the two approaches.

            – See more at:

            The subject of reserves does not exist in a void. Renewables must be compared to the rest of the generation system.

            Grid managers have to maintain hot backup contingencies for failure of their largest single generation plants, typically coal, hydro or nuclear in the 1 GW range. Wind energy doesn’t rank as a grid management issue until you get into > 20% ranges, and even then it isn’t a particularly hard or sudden problem compared to dealing with a nuclear plant that suddenly isn’t there. [15]

          • owen m

            Well your quoting from invested interests. SEAI are not reliable – they put disclaimers on their reports saying “there are clear limitations in our analysis” and that their reports are only an indication and cant be relied on. My purpose here is not to educate posters here but to see how reliant you all are on reports by invested interests and how you are victims of wishful thinking. I have done my own analysis based on independent dispatchable plant figures from the Irish TSO Eirgrid (actually Eirgrid are biased in favour of wind although they do state quite a few reservations too). I am satisfied that the analysis here is incorrect and reality does not bear out the theories in this article (at least where Ireland is concerned) . And so I question what is happening in USA and elsewhere, my hunch is that dispatchable plant has soared here too with increased penetration of wind.

          • eveee

            Owen, – Then show us your calculations and your references . There are plenty of references from NREL and peer reviewed papers using historical demand and wind data that show reserve requirements are low.

          • Bob_Wallace

            Look at how easy it is to back up wind. And be sure to read the sentence “and, as it happens, less than a tenth of what was needed to back up conventional power stations”.

            “It has become an article of popular faith that building wind farms also involves constructing fossil-fuelled power stations for back‑up when the weather is calm. As a result, some opponents go on to say, wind turbines do little or nothing to cut carbon dioxide emissions.

            Now the National Grid has studied what actually happens in practice, with explosive, if surprising, results. Between April 2011 and September 2012 – its head of energy strategy, Richard Smith, told the Hay Festival – wind produced some 23,700 gigawatt hours (GWh) of power. Only 22GWh of power from fossil fuels was needed to fill the gaps when the wind didn’t blow. That’s less than a thousandth of the turbines’ output – and, as it happens, less than a tenth of what was needed to back up conventional power stations.

            It proved to be much the same with emissions. Wind saved nearly 11 million tonnes of carbon dioxide over that 18 months; standby burning of fossil fuels only reduced this by 8,800 tonnes, or 0.081 per cent.

            Not surprisingly, given these figures, no new fossil‑fuel power station has been built to provide back‑up for wind farms, and none is in prospect.”


          • owen m

            well then why did Irish TSO accept connection agreements for new thermal plant in the past few years ?

          • Bob_Wallace

            I can’t answer that for you Owen.

            Perhaps Ireland had a very primitive, inflexible grid and needed more dispatchable capacity.

            Whatever, going forward Ireland will have the ability to use cheap, clean wind energy and fill in with not so expensive NG. That means that Ireland is on its way to being a responsible world citizen and lowering its CO2 footprint.

            Next, you people need to start installing storage so that you use even less NG.

    • Mint

      Spinning reserve is not the issue. An increase or decrease in wind is physically incapable of propagating even a mere 200 miles in a couple hours, so that precludes highly correlated spikes/dips across many wind farms. It’s only when you go beyond the timeframe of a few hours that wind correlation is an issue.

      The long term problem is the need for general dispatchable power to fill in the blanks. Low output for a few days or even a week is the real problem with wind.

      US utilities are freaking out a bit, but once the dust settles, the survivors are going to charge through the roof when renewable output is low. It’s a game that peaking plants have been playing for a long time (the northeast US saw $500/MWh at times this past winter), and they’ll only do it more with the opportunity provided by renewable variability.

      EGS sounds like a dream. I hope it pans out for more than just a few percent of demand. It seems to me that even a single location with the right circumstances to make it economical could be expanded endlessly. But it should be noted that if we had 50% wind/solar penetration forcibly built via subsidy, then it’d be that much harder for baseload like EGS to flourish, as only half of its energy would produce non-zero wholesale prices.

      • eveee

        Perhaps a reference or two might be more definitive than, “It seems to me”. Please provide your reference for “Low output for a few days or even a week is the real problem with wind.” over an area the size of MISO or larger. Or just show a week of low wind output, and describe what you mean by “low”. Vague generalities are not too scientific, if I may be a little vague.
        Let me cut to the chase. There is no “week” of low wind output over an area that large in the Midwest. I doubt there is in EU, either. But feel free to provide references for an area that large in EU and show us the “week” of “low” wind output. I doubt the area includes Denmark.

        • Mint

          I don’t know where to get data that meets all your requirements. MISO historical data isn’t public. The best I can find is this:

          They have a collection of hours with extreme demand over the years, and it just so happened that there are 5 data points from 8/1/2007 to 8/8/2007, and wind output was below 4% of capacity each time.

          I found this for Europe:

          Page 28 is for 7 countries, from Spain to UK to Denmark to Germany, 69-75GW capacity, one year of data (2012). For 12 days in August, average output was 8GW. For 4 days in Oct, avg output was 6GW.

          It’s not useful to have a rigid definition of “low”, but if you want one, lets say half of average output.

          • eveee

            The capacity credit is probably a good value to use for the low number. This is supposed to be about 15% of nameplate. Nameplate does not mean much relative to conventional, its just the potential maximum output. The economics and operation are completely different. You are right that numbers can be difficult to come by. The capacity credit indicates a value of power that is available something greater than 90% of the time, I don’t know the exact figure. So for MISO, which has 12GW of wind, that is 1.8GW. That means you can observe it for a month and get some idea of that. My observations are that its true. The kicker there is that since power is proportional to wind velocity cubed, there is much more energy available than a linear multiplication would indicate. When you look at the daily MISO wind output, that becomes apparent. There are many days, even consecutive days with generation in excess of 5GW. There was a lull, the lowest I have seen, down to about 1GW for about three hours recently. MISO wind is lowest in summer. West Coast is opposite, at least for current land installations, which are fewer and concentrated in only a few areas.

          • Mint

            Capacity credit for wind is a big debate, because wind has correlation while thermal does not. The grid system needs much, much better than 90% uptime, so that figure is rather meaningless.

            If you have 40 independent gas plants, and each has a 90% chance of being capable of 50MW output at any time, then there is <0.01% chance of these units outputting less than 1.4GW:

            Wind doesn't behave like that. 15% CC for each of the 500+ turbines generating 12GW of wind would imply 1.8GW CC. If the aforementioned 40 gas turbines each got 90% CC, then they too would get 1.8GW CC. But as you've observed, the chance of 12GW wind outputting less than 1.4GW is far FAR greater than 0.01%.

            That's why wind doesn't let you permanently close much FF at all (certainly not 15%). You don't necessarily need any more spinning reserve, but you do need FF capacity ready to go online. That’s why Budischak still needed FF capacity almost equal to peak demand to fulfill all demand, and Diesendorf needed lots of biogas and solar thermal with storage (which is really expensive).

            The WWSIS report further confirms the fallacy of 15% capacity credit on page 42. For the high wind case (64GW wind, 25% energy), output is below 5GW ~3% of the year (250 hours), and hits minimums of ~2.5GW. So what would the wind+storage minimum output be as a function of X GWh of storage? We need the raw data to figure that out.

            Regarding MISO data and how low generation you can get in a 5- or 10-day span, I just can’t trust your casual observations/memory from the last few years. I’ve seen too much data showing that prolonged low wind can happen, even across geographically large areas.

          • eveee

            I don’t know what you mean by debate. The peer reviewed literature is clear on it. It depends on some factors, but there is little doubt. The studies show the frequencies and the data has been taken. You would do better to begin studying how reserves are computed than to try to figure out a hypothetical example. There are a huge number of professional papers available. The 40 gas turbine example may not reflect how ISOs actually calculate reserves and probabilities. There are papers on how reserves are calculated for wind.

            Get familiar with terms like LOLP, LOLE, and ELCC.

            Here is a laugh. I just found the MISO system wide capacity credit planned of r2014-2015. Guess what. Its 14.1%.


          • Mint

            The real laugh is that I gave you that link 4 days ago. Look 3 posts up.

            Yes, there is a debate about wind CC. Take a look at how different ISOs treat the issue:
            I read this a long time ago, and have known about all those terms for a while.

            I just explained to you why ELCC has been traditionally calculated that way. Fossil fuel outages are independent of each other, and therefore ELCC can be used to compute reserves needed for 99.97% uptime (LOLE 1d/10y).

            BTW, did you even read the MISO link? Look at the days of peak load in July 2012: 659MW wind, 1152MW, 1159MW, and 14.1% ELCC would imply capacity of 1660MW. Do you think thirty-three 50MW gas plants would have such low output on those days? Go ahead and do the calculation yourself to see the odds of that happening.

          • eveee

            If you don’t believe my eyes, believe yours. Watch MISO for months. I am sure you will find some “lulls”, just don’t expect a weeks worth. 🙂 And I mean 1GW or less. Summer is the worst. You are probably going to see some hours here and there, I don’t know. I have not seen it in summer yet. Let me know when you see it drop below 1GW for a10 day span. I will be watching it, too. 😉

          • Mint

            Months is woefully inadequate when the standard of reliability for the grid is 1 day outage per decade. I need years of data.

            And what basis do you have for saying anything above 1GW is not low? 12GW of wind has an average output of around 4GW, so even if it drops below 2GW, that’s low in my book.

            To get 25% wind penetration, WWSIS tells us we need 64GW of wind. Say average output is 22GW, or the same as 25x 1GW nuclear reactors with 88% uptime. If those nuclear plants ever output less than 11GW total, wouldn’t you call it low? You should, because the odds of that happening are well under one in ten million. Even 16GW is low, as it would only happen 1 day per decade.

            I stand by my assertions. 50% of average is low. 2GW avg from MISO over a week or two will indeed happen now and then.

          • eveee

            I didn’t say you should use months as a scientific standard, I suggested you look at MISO for months to inform yourself If you already knew MISO capacity credit was 14.1%, why ask? Make a specific statement and show references. Choose any level of wind and find out how long output is below that level. There are probability charts in NREL papers. It is not meaningful to reference wind output by itself. All grids must have a combination of sources to follow load now and in the future.

          • Mint

            Why ask? What did I ask, exactly? I said there’s a debate about how much capacity credit wind should get, and provided a NREL link showing different grids give different credits.

            ELCC is not the final word in reliability, because it’s based on some methodology for a single plant’s reliability (e.g. your 90% figure), while the target system reliability is 1d/10y outage. That’s what I’m trying to explain to you but you seem unwilling to accept. Nobody wants a grid with only 90% reliability.

            So then you have to worry about outage correlation, which is a non-factor with FF, but notable with wind/solar.

            Choose any level of wind and find out how long output is below that level. There are probability charts in NREL papers.

            I have already referenced such charts in the posts above. Why do you refuse to look at them?
            Page 42 (PDF page 87). High wind is 64GW nameplate, 34%CF, 25% energy.

            Unfortunately, we can’t zoom in on the graphs, so reading off values is a bit difficult. But, as I stated before, for 64GW wind, total output is below 5GW for ~250 hours per year.

            All grids must have a combination of sources

            There’s another chart for this on the same page. For the high wind mix with 33% of overall energy coming from wind/solar, peak net demand, defined as load-(wind+PV+CSP), only dropped about 13%. Most of that was done by solar+storage.

          • eveee

            You seem to think that capacity credit for wind is a debate. I don’t see debate in the profession. Where is the debate at MISO? They published the capacity credit. Show a reference to the debate. You seem confused. Probability charts in NREL are not based on one WTG. Neither are ELCC in WWS based on one WTG. One day per decade is the goal for an entire ISO system, not one wind farm or any single generation source. There are plentiful papers on the subject of wind integration. They conclude its not a problem. Read. The debate about the effectiveness of renewables is over.



          • eveee

            Bucischak, “FF capacity almost equal to peak demand to fulfill all demand”. Reference please.

  • Bob_Wallace

    Mike – have you seen this?

    ““According to a panel of researchers at the Windpower 2014 conference, continued improvements in wind and solar technologies are making them a threat to natural gas.Ryan Wiser, a staff scientist at the Lawrence Berkeley National Laboratory, highlighted innovations in blade and rotor design. Advances in materials have allowed the design of longer turbine blades and rotors that can operate efficiently at lower wind speeds. Since 2012, a “massive proliferation” of these turbines has driven average capacity factor increases up by 10 percent at every level of wind resource. As a result of these advances, costs are falling; preliminary data shows that the average 2013 power purchase agreement was at $0.021 per kilowatt-hour.

    “These are not your grandfather’s wind turbines,” Wiser said. “They are not even your older brother’s turbines.””

    • JamesWimberley

      The same article also has this:
      “In utility-scale solar,
      PPA prices are down in some places to slightly more than $0.05 per
      kilowatt-hour, due in large part to the emerging practice of oversizing
      the module-to-inverter ratio, according to Wiser.”
      And unlike wind rotors, the inverters can simply be upgraded when they are cheaper.

      • Bob_Wallace

        I saw something about a recent solar PPA for less than $0.05. They didn’t say how much lower.

        Five cents might be business as usual in the SW by the year’s end.

    • Yup, I was at Wiser’s presentation and spoke with him. Amazing stuff. It hasn’t been reposted on CT yet, but I blogged about it at E&PI.

    • Mint

      Doesn’t that mean it’s time to phase out the PTC?

      If wind can beat 3c/kWh (the fuel cost of CCGT in the US) w/o the PTC, I will reverse all objection I’ve ever had to it, because at that point even CCGT operators will be building them to save on fuel.

  • Hans

    The sad thing is, all the arguments that you debunked will keep on being used.

    • Bob_Wallace

      It’s the common right wing strategy.

      Tell a lie often enough and some people will think it true.

    • Of course, but by getting the message out there and targeting it at press, policy makers and social license communicators, I help shape the approach to countering it. If smart people know what opponents are going to throw at them, and what the data says, then they can create ways of countering the messaging. That’s a big part of what I’m doing with my Windy Fella hat on.

      • Hans

        I agree with you. Don’t let my short burp-up of cynicism discourage you. Keep up the good work!

      • Mint

        Well, I’m going to challenge a few of those claims.

        The chart you showed about plant efficiency is about cycling costs only. Check pages 14 & 15 in the study you quoted:

        Running a natural gas plant at less than full capacity increases CO2 and NOx by 9-22% per kWh.

        Another factor not considered is that wind provides less incentive to replace less efficient gas turbines with CCGT, both due to ramping and operating at lower CF. That’s not something you can capture with before/after comparisons.

        Also, may I ask what the source is for the top chart?

        • Your first point is, I believe, covered by the chart in point 3 in my post. Nothing being hidden there.

          Gas vs CCGT is immaterial compared to wind vs coal, to your second point.

          As for your last question, the chart is from the UK study on this subject referenced elsewhere in the article.

          • Mint

            Ah, you are correct about the chart, as the first column is not about cycling. But I don’t think your point #3 headline is quite justified. Even though you are correct in busting the myth that wind not reducing emissions, I think the increase emissions from FF plants are significant. There’s the chart/table I pointed out (9-22%), and your top graph shows a slope of -0.92 instead of -1.

            These are relatively low levels of wind penetration, too. The departures from the ideal will be more significant at the higher penetrations that people are calling for.

          • Those numbers are at 33% of demand met by wind and solar. Are you suggesting that isn’t significant?

            I agree the new DOE Vision is 35% wind alone by 2050 but the amazing reduction in gas and coal generation under that scenario makes the argument you seem to be making irrelevant.

          • Mint

            I never said not significant. I said relatively low, and the 16.5% figure is exactly that, at least compared to 35%. The 16.5% solar isn’t really relevant to any of the points I’m making, especially since much of it is CSP.

            You can call it irrelevant, but I don’t think 10-20% is “little effect”. Anyway, I think this discussion is getting pointless. Wind certainly results in big emissions reductions, even if it’s 29% instead of 33%.

          • Absolutely agree with your last sentiment.

            But 16.5% for wind — and that’s not nameplate but actual generation — is closing in on nuclear at 19% in the USA, and with most of the reduction being in the leader coal which is likely going to be less than 16.5% by the time wind and solar are at that number. With nuclear having at best replacement and likely diminishment for the next couple of decades, it’s likely 16.5% for wind energy will be tied for second with solar after natural gas before too long. It might be tied for third if nuclear stays flat instead of diminishing as it is doing in almost every other country.

            It’s hard to understand why you would consider that relatively low in a mixed generation grid. In France, sure (although it’s dropping 30% of its nuclear fleet in favour of mostly wind energy as well).

          • Mint

            Environmentalists that want to stop fracking, shut down coal, and shut down nuclear are looking for a lot more than 16.5% wind. That’s what I mean by “relatively low”.

          • Ah. Got it. Personally I can wait a while to shut down nuclear as the clear and present danger is warming but I agree completely about fossil fuel generation.

            35% wind and roughly the same solar in the USA by 2050 is a good vision for the DOE to be promoting. Wish it could be sooner, but there’s only so fast a huge and expensive infrastructure that hundreds of millions depend upon can be transformed.

  • Zach

    Your data is really old (from 2003) for the energy payback. Wind has gotten a lot better since then, pv has gotten a ton better.

    • Links please, love to have them. The old data is stunning, but new data that’s better is more stunning.

  • John Ihle

    not sure if your life cycle analysis should extend past the 20 year period. Developers are financing projects beyond 30 year timeframes, some, I understand, up to 35 years. Why not? Infrastructures are in place, e.g. concrete, underground, substation, and interconnection agreement, etc. and if the project has to re power at some point there are various financing tools available. There is a lot there, imo, that may not be considered with respect to longevity and over all value.

    • Energy industry standard is 20 years because it’s long enough to allow decommissioning to be present without being ignored under net present value rules without letting it dominate the conversation, while allowing everything to be commonly assessed.

      Lot’s of bright people have picked on 20 years and it continues to be the right choice.

      • John Ihle

        I’m sure they’re bright and I get it, ie the certification/standards process and subsequent 20 year lifecycle of a wind turbine. However, 20 years leaves a lot of value not considered by the host community, etc…. especially when considering land leases/infrastructure (not to mention ppa’s) typically which go much longer than 20 years. In the past I’ve seen land leases go to 99 years. I’m not suggesting you’d get 99 years out of a wind project but, having said that; I highly doubt a wind project will decommission in year 21 or 22. There is a lot, imo, wrong about the 20 year standard, which is based on international certifications and inferences. However, a good understanding of the technology and maintenance needs are factored in (for a ppa) and like I said you’d likely run the project well beyond 20 years. It is the way it is. Been there, done that.
        From my perspective, farmers/landowners, communities and state legislatures need to be educated about realities when signing long term land leases, hosting projects and/or devising laws. It’s somewhat of a separate issue but relative to your 20 year standard value. Bottom line is that developers and corporations suck big time value out of host communities and it’s foolish not to understand what they’re giving away.

        • Bob_Wallace

          We’re just now replacing out the 30 year old turbines at Altamont Pass. One should expect more modern technology, especially with all the built in sensors, to last longer than 1980s turbines. Just look at modern cars.

    • jeffhre

      Aren’t the tax benefits gone in 15 to 20 years? At such time owners and developers could look at replacing capital intensive items if there are benefits. Large items like rotors, transmissions, even turbines could be updated and replaced, new financing agreements and partners acquired and another 15 to 20 years of operations at higher efficiencies could result.

      Other adjustments like control systems and sensor updating, if not recently improved could be undertaken as well. With current PPA’s at $.021, what costs would the updated farms be operating at. After all, they will as you stated not have to renew permits, and will using towers and supporting infrastructure that have long since been amortized? Amazingly cheap power could be on the horizon with wind.

      • Bob_Wallace

        The production tax credit (PTC) goes away after the first ten years of production. If the wind farm owners take the investment tax credit (ITC) that’s a first year and done write down. At times there have been accelerated depreciation programs which bring the writeoff forward which means it’s ended sooner. (Haven’t been keeping up with the ITC and acc dpr stuff.)

        A lot of farms are apparently upgrading with newly designed blades from GE. Since the increase can be as much as 10% it’s possible that a brand new farm might decide to upgrade. And there’s GE’s new software which can add another 5%. No sense in waiting until the end of 20 years to install that.

        • jeffhre

          Yes that is true since the improvements have had very rapid payoffs. Though the reason I have mentioned it is not to spotlight the evolving M&O practices or near the term expenses increasing efficiency that we are seeing.

          For background, what I have noticed from the real estate industry is, that when all the preferential tax treatments expire, a property is likely to be turned over to a new group of participants at the helm, and there are often a lot of renovations, signaling a repeat of the project that started with the properties initial development, 20 or so years earlier. Essentially an “all new project” based on the existing infrastructure.

          If installed wind proves to be similar, and the next generations wind projects piggy back on existing in-the-ground infrastructure, wind will be incredibly inexpensive going forward.

          • Bob_Wallace

            I’m not sure I’m following you. Let me see…

            You’re suggesting that the first owners might burn through the “first ten years” PTC, sell the farm to a new owner, that person might do renovations and then be able to restart the PTC?

            I don’t know enough about the way the subsidy bill is written but I imagine:

            a) It would only be done once (or a handful of times). After it happens and word gets out the next subsidy bill would nix that sort of thing.

            b) There won’t be any subsidies for (onshore) wind after a few more years. Perhaps only for a very few more years.

            With wind now selling for 2.1c/kWh that means production costs of less than 3c/kWh. Add back in the 1.13c subsidy. Remember there are owner profits and likely transmission costs which are not part of production costs which, together, pull the 3.23 down a bit.

            With wind at 3c and falling it’s going to be hard to sell a lot more years of subsidy.

            Remember, the wind subsidy bills are sunsetted. Unlike subsidies for fossil fuels, wind has to go back to Congress each year and re-pitch its case. Asking for federal subsidies when you’re the lowest price (new) electricity provider would take some powerful strong lobbying.

          • jeffhre

            “You’re suggesting that the first owners might burn through the “first ten years” PTC, sell the farm to a new owner, that person might do renovations and then be able to restart the PTC?”

            Yes, if the entire tax treatment is included, various forms of depreciation etc, not just the sure to be terminated PTC.

          • jeffhre

            Reply . is . gone!

            No to restart of PTC which will likely disappear altogether. Yes, to new owners, as the mix of financial partners and project participants could trigger an evolution of tax treatment (such as response to depreciation and new ownership status).

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