Wind Generation Does Not Reduce Fossil Fuel Use and Emissions Enough To Make it Worth The Public Investment
There have been some interesting recent discussions about the overall effect of introducing large amounts of weather dependent wind energy into a complex power grid supplied by more controllable forms of power generation. The conversations have been building on research conducted over several years as countries and states gain experience in integrating ever larger quantities of wind into their power grids. The research has not been widely discussed, partially because the organizations that should be interested in determining how well their investments are performing are not terribly interested in sharing that information with the world.
The conversation, however, should enter the mainstream. Robert Bryce, author of Power Hungry: The Myths of “Green” Energy and the Real Fuels of the Future has been introducing more people to the results of studies questioning the measured effects of increasing quantities of wind generation on fuel consumption and emissions.
On August 23, 2010, he published a column in the Wall Street Journal titled Wind Power Won’t Cool Down the Planet that pointed to results from a study conducted by Bentek Energy of the actual emissions effects of wind power in Colorado and Texas. In the form reported by Mr. Bryce, the results left some room for criticism, partially because Bryce weakened the strength of his argument by using pounds as a unit to produce a big number in one sentence and then using tons as a unit to provide a smaller number in the next sentence.
Bentek found that thanks to the cycling of Colorado’s coal-fired plants in 2009, at least 94,000 more pounds (Aside: 47 tons End Aside.) of carbon dioxide were generated because of the repeated cycling. In Texas, Bentek estimated that the cycling of power plants due to increased use of wind energy resulted in a slight savings of carbon dioxide (about 600 tons) in 2008 and a slight increase (of about 1,000 tons) in 2009.
Unfortunately, mixing units left open a line of attack against the credibility of the study. Another line of attack that has been used against Bryce’s work is that the study he quoted was funded by the Independent Petroleum Association of the Mountain States. Bryce, though often a free lance writer, also has some funding ties to the fossil fuel industry. In the energy world, it is difficult to find a knowledgeable source of information that does not have some kind of ties to one energy source or another, so my advice to “follow the money” usually means recognizing the potential for bias as you evaluate positions and information.
Michael Goggin, Manager of Transmission Policy for American Wind Energy Association (a wind industry lobbying group), took aim at Bryce’s article using all of those lines of attack in a post titled Mythbusting Fact: Yes, Wind Does Reduce Emissions and in a related fact sheet titled The Facts about Wind Energy’s Emissions Savings. Michael uses some loaded words as he casts aspersions on Bryce’s motives with the following statement:
We want to share with you a bit about the latest attack on renewable energy which has been on Fox and in the Wall Street Journal this week. Robert Bryce of the Manhattan Institute, an ExxonMobil and Koch family funded advocacy group has been on discussing his book which, in turn is based on a recent Colorado report paid for by the Independent Petroleum Association of Mountain States (IPAMS).
The words chosen in that statement are full of special meaning to the choir often associated with renewable energy projects. As Goggin frames it, the primary news outlets interested in pursuing the story are Fox News, often associated with the political right, and the corporate oriented Wall Street Journal.
Goggin also links Bryce to both ExxonMobil (which has a frequently reinforced reputation within the devoted renewable energy fan club for funding climate skeptics and spilling a lot of oil in Alaska) and the Koch family, a not-so-well-known group of wealthy oil men who are the subject of a recent lengthy article in the New Yorker titled Covert Operations; The billionaire brothers who are waging a war against Obama. It is quite evident that the aim of the AWEA’s communication arm is to paint Bryce’s questioning attitude and reported results as simply an effort of the “dirty” fossil fuel energy industry and its media friends from the right.
I crossed paths with this back and forth between different views of the value of wind turbine investments when an Atomic Insights reader sent me a link to a specific analysis of the impact of replacing coal with a combination of wind and natural gas in Ontario, Canada.
According to that detailed analysis, written by Donald Jones, a man who has earned the right to put the designation of “P.Eng.” (professional engineer) behind his name, replacing existing coal stations in Ontario with a wind/gas combination has been an expensive bust if the goal is to reduce greenhouse gas emissions. Donald is very careful not to make sweeping statements about wind in general; he limits his analysis to the specific conditions applicable to the Ontario power grid where the electricity supply in 2009 had the following composition: nuclear – 55.2%, hydro 25.5%, gas 10.3%, coal 6.6% and wind 1.6%.
The challenge that wind is giving the Independent System Operator in Ontario is that they have to vary the output of the few controllable generators that they have on the system in order to keep a stable 60 hz frequency on the grid. More often than not, wind displaces already emission free hydro, but in the case where coal or gas fired output is varied to accommodate wind, the stop and start operation reduces fuel economy enough to eliminate any fuel or emissions reductions.
Aside: Though AWEA’s Goggin denies that this fact of life occurs when operating real equipment, most people who drive automobiles will recognize that their fuel economy varies substantially depending on whether they are driving long and steady highway miles or stop and start city miles. A smaller portion of the population might even recognize that city mileage can drop even more if you have a heavy foot on the accelerator and have to break sharply when the light turns red. Wind generation can have a similar pattern on certain blustery days, requiring other generators to do the stopping and starting to keep the grid output matched with demand. End Aside.
The AWEA is apparently monitoring mentions about its technology in social media. Even though Donald Jones’s post was specifically focused on the Ontario grid, with its already low emissions levels due to a majority of hydro and nuclear generation, AWEA’s Michael Goggin discovered the conversation responding to Donald’s post and posted the following comment:
Actually, all of the studies and data that were not paid for by the fossil fuel industry show that the emissions benefits of adding wind energy to the grid are even larger than the amount that is directly offset. We’ve summarized the results of these government-funded studies and data here:
http://www.awea.org/newsroom/pdf/08-27-10-Wind_and_emissions_response.pdf
Michael Goggin
American Wind Energy Association
That comment intrigued me enough to go and read the linked document and do some additional research. (By the way, I admire the way that
the AWEA is using modern techniques to keep up with the public perception of its product. They are almost as good at that important function as David Bradish, Mark Flanagan and their friends at the Nuclear Energy Institute (NEI).) Here is the comment that I added to Donald’s post on Wind Concerns Ontario.
This thread has provided some interesting food for thought. Though the initial post was clearly focused on a particular wind development effort in Ontario, and describes the effect of adding a wind and gas combination to that grid, the AWEA jumped in with a link focusing on some carefully selected analysis in Colorado and Texas that blamed questions about wind’s CO2 reduction on the fossil fuel industry.
I suspect that target was chosen because the fossil fuel industry tends to be a good “boogeyman” in public discussions about energy, with wind and solar trying to claim white knight status.
The relationship, however, between wind and the fossil fuel industry includes a large number of different players who have different agendas. In Ontario, there is a choice being made to eliminate coal and attempt to replace it with a wind and gas combination. Interested players – like Energy Probe – are certainly not anti fossil fuel, they are pro natural gas and anti-coal.
The current CEO of the AWEA, Denise Bode, has a deep, lifelong history in the oil and gas industry. Here is an interesting quote:
“Bode dismisses the criticism, arguing her fossil fuel background is an asset. She knows the strategies of oil and gas businesses, she said, and understands how they can partner with wind. Her change of political parties, she said, means she understands both and can bridge differences.
Anybody that knows me knows that I don’t do things I don’t really care about,” Bode said in an interview. “I chose this job because it was something I was passionate about, that I felt like I could use all the experience I had, working 30 years in the energy area.
“I know,” she added, “where everybody’s buried in energy.”
Here is another interesting quote from a political figure who is closely identified with renewable energy mandates – former Senator Tim Wirth. He was speaking to the Colorado Oil and Gas Association in July 2009:
“Many of you have, for reasons that are absolutely beyond me, decided that you are going to oppose the solar and wind industry, just at the time that is the teddy bear of American energy policy. Everybody wants to embrace solar and wind. But what happens when the wind doesn’t blow? What happens when the sun doesn’t shine? It’s natural gas that should be filling in that gap! You should be the closest buddy of the wind and solar industry and all be kissing each other in the neck and walking together into get this legislation passed.”
Smoking Gun Attack on Nuclear From Aloys Wobben, Enercon Managing Director
Wirth is also closely associated with the natural gas industry, so his recommendation indicates that there is a strong faction within that industry that understands that increasing wind penetration also increases natural gas sales, so the two deep pocketed industries often go arm in arm to politicians for mutual benefit.
It is disingenuous for the AWEA to blame the fossil fuel industry for all questioning of the overall effect of larger and larger wind fractions on CO2 reductions. The response paper that Michael Goggin linked to also included a footnote (8) that demonstrated a pretty significant slant with the following statement:
“Electric demand already varies greatly according to the weather and major fluctuations in power use at factories, while electricity supply can drop by 1000 MW or more in a fraction of a second when a large coal or nuclear plant experiences a “forced outage” and goes offline unexpectedly, as they all do from time to time. In contrast, wind output changes slowly and often predictably.”
There is an excellent response to this comparison between wind reliability and nuclear plant reliability at
My position in this discussion is that I favor more nuclear power, which is a technology that has a much stronger empirical record of reducing all emissions from electrical power production, not just CO2. It is also a technology with the demonstrated capability to play better in a grid with varying demand – France uses load following nuclear, and the submarines that I used to operate could change power even quicker than most diesel engines or gas turbines.
Rod Adams
Publisher, Atomic Insights
It is quite amusing for me to watch others in the energy industry duke it out over market share and public reputation. I would bet that if the topic was using nuclear energy to reduce CO2 emissions, other air pollution effects, fuel consumption and the cost of electrical power, most other energy producers would join in a chorus to sing about the potential for catastrophic impacts (even if they also mention that they believe that the probability is quite low). They would almost certainly refer to our inability to agree on a solution for our waste challenges.
I am often accused of being completely biased and unwilling to acknowledge the potential utility of other energy sources outside of nuclear. I plead guilty as charged, though I think that sailing is a great sport; I still have a guilty habit of being a bit of a solar collector with a deep tan in the summer; and I harbor no illusions about the potential for the development of fission powered automobiles or aircraft. I hope that at least some people recognize that I moved to my position about energy after dedicated study involving staring at steam tables, learning about fuel source heat content, learning how to predict the intensity of solar energy based the sun’s altitude, determining the relationship between wind velocity, blade area and power output and performing graded calculations.
That formal, classroom study has been reinforced by actually operating nearly every kind of power source on the market today. (I cannot claim to have ever operated a coal fired power plant, but I have toured a number of them to the detail of putting my hands in the coal pile, watching the conveyors, peering into the boilers, and observing operators taking sample readings of the emissions level pouring out of the 200 foot tall stacks.)
Additional Reading
Kent Hawkins published a four part series on the issue of wind’s effects on emissions levels on MasterResource. Part IV of that series is titled Wind Integration Realities: The Bentek Study for Texas (Part IV). I recommend the entire series; there are links to the previous parts of the series at the fourth installment. (Note: Having this series on MasterResource, a blog that does not hide its petroleum favoritism, also provides some interesting food for thought about the complex relationship between the “fossil fuel” industry and the non nuclear alternatives to fossil fuel.)
Elsevier Energy Policy Journal (June 2008) – Will British weather provide reliable electricity?
Connexion France (J
une 2010) – Wind turbines: Con of the century
Brave New Climate (September 1, 2010) – Does wind power reduce carbon emissions? Counter-Response (Barry Brook at Brave New Climate has a guest post from AWEA’s Michael Goggin on his blog today. Hat tip to Finrod for the link.)
Update: (September 1, 2010 12:37 pm) Just in case you are like me, a self-admitted technical elitist who believes that people really should study hard and earn some sound credentials before influencing public decisions on complex technology issues, here is Michael’s qualifying background:
Michael represents the wind industry on transmission matters, coordinates member input on the development of policy positions, facilitates the exchange of information between members, handles press inquiries on transmission-related issues, and advocates policy positions that advance wind industry interests. Through these activities, he works to promote transmission investment and advance changes in transmission rules and operations to better accommodate wind energy in the power system while maintaining system reliability. Prior to joining AWEA, he worked for two environmental advocacy groups and a consulting firm supporting the U.S. Department of Energy’s renewable energy programs. Michael holds a B.A. with honors in Social Studies from Harvard College.
Update: (posted on September 3, 2010 at 1712)
MasterResource (September 3, 2010) – Germany: Wind and the Power Pool Savings Myth
Renewable Energy World (September 1, 2010) – The Facts About Wind Energy and Emissions: Anti-wind groups are attempting to defy the laws of physics with their claims
Update: (posted on September 7, 2010 at 0807) – The intrigue continues with a September 7, 2010 article from McClatchy-Tribune regional news titled Wind industry fights to defend its position as clean energy alternative that is posted on Energy Central. Denise Bode, CEO of the American Wind Energy Association and former president of the Independent Petroleum Association of America (IPAA), is quoted in the article as saying the following:
“We’ve been under attack by the fossil fuel industry for the last six months.”
Ms. Bode also has suggested that America’s future is dependent upon a federal renewable energy standard and said that she is in the fight “to the bitter end.” Her former colleagues at IPPA, however, have worked hard to reject any efforts to tax oil and gas revenues in order to support renewable energy system developments.
Trade groups for oil and gas companies, including the Independent Petroleum Association of America, have not taken a public position on a renewable energy standard.
Jeff Eshelman, a spokesman for the group, said the organization has always cited the importance of all domestic energy sources.
“However, we do take issue with proposals that call for taxing American oil and natural gas companies to subsidize nonconventional energy resources,” he said.
Barry Brook has permitted Michael Goggin to publish a guest post on Brave New Climate concerning this:
http://bravenewclimate.com/2010/09/01/wind-power-emissions-counter/
Rod Adams wrote:
Aside: Though AWEA’s Goggin denies that this fact of life occurs when operating real equipment, most people who drive automobiles will recognize that their fuel economy varies substantially depending on whether they are driving long and steady highway miles or stop and start city miles. A smaller portion of the population might even recognize that city mileage can drop even more if you have a heavy foot on the accelerator and have to break sharply when the light turns red. Wind generation can have a similar pattern on certain blustery days, requiring other generators to do the stopping and starting to keep the grid output matched with demand. End Aside.
The owners of wind turbines force increased fuel costs and CO2 emissions from fossil fuel plants, and bear none of the costs. On top of that, these fossil fuel plants are forced to cycle more often, increasing the maintenance costs (especially on plants that were designed for base-load operation), and once again the wind turbine folks skate free.
Consumers can consume electricity intermittently, and still pay the same price as if they had consumed the kWh’s continuously. This has contributed to the illusion of wind power with their claims of competitive prices per kWh
Jerry! you may have hit on the answer – people wishing to buy only wind-based electricity should get cut off when the wind doesn’t blow! Wind’s irregularity of supply matched by imposing it on willing portions of the demand population – and no backup required.
Bit of a problem when (as here) the local city trains claim to run on wind electricity though.
This article, http://www.quadrant.org.au/magazine/issue/2010/7-8/the-great-renewable-energy-rort from a right leaning Australian political magazine says, combined cycle gas turbines will save more green house gases than wind backed up by open cycle gas turbines – among the usual litany of wind power negatives, written by an accountant it focusses on public costs health etc. I also watched a recent British documentary, BBC-Britains Secret Engineers, that claims that gigawatts of wind farm projects have been put on hold because of blade interference with aircraft ground control radar, military and civilan. Wind power community costs have not been fully recognised.
I get 3-5 MPG better gas mileage just by using cruise control on highway trips over not using it.
1. The most efficient CCGT’s can NOT be ramped up rapidly, nor cold started.
2. The least efficient once through gas turbines can do both. Result – more emissions.
3. Variable generation (wind/solar) creates high reactive currents on the transmission grid. Result – wasted power. Second problem – extra capacitors (big bucks) on the transmission lines to negate the reactive VARs.
4. Backup and the 10% mandated “excess capacity” units MUST (FERC regulations) be “spinning.” (Hydro, pumped storage and some OTGTs exempted if proven capable.) Result – older, less efficient units running at lower power levels that are even less efficient. FACT: It takes more fuel per kW of power when the generator is at 10-20% capacity than when at 90-100% capacity. For some units this could be 5-10 times as much.
One clarification: Is #3 because wind turbines effectively motor, and therefore effectively act as inductors and “lag” the grid – requiring power factor correction capacitors – when the wind stops blowing?
Or is it a case of distribution lines to unreliable distributed “resources” (and I use that term loosely) being too small for the generator as unreliable distributed generators aren’t logically located within the distribution system’s topology, leading to I
Yes the turbines will “motor” if making to little power. The protection circuits will have anti-motor trips that prevent them from turning into a big fan, but they will still produce measurable VARs. If you look at a graph of the power generated by wind/solar per hour (or smaller interval) you will note an uneven unpredictable curve. This causes problems with the moving of electricity from one area to another. Just like water goes from the highest pressure to the lowest pressure, electricity goes from the highest voltage to a point of lower voltage. Complicating matters is the fact that the frequency must be maintained (with looser minute-to-minute tolerances than day-today) at 60.000 Hz. When a windmill/solar panel puts out more voltage, unexpectedly, voltage goes up in that area and some other power plant speeds up increasing frequency and creating VARs and wasting power. Conversely when the output of these highly variable sources goes down, voltage drops in this area, electricity moves to this area and away from where they were trying to move it to (some other county or state) and the base-loaded plant now slows down, creating VARs again, wasting power (actually the fuel needed to create this useless “work.”) On most transmission grids a plant that creates “capacitive” VARs is helpful, if created when and where needed, as most of the VARs are reactive and that is the reason for the large capacitor banks. The utility I worked for has sold electricity to areas several states away. This requires the dispatchers in each area along the way to push electricity in that direction. No, I don’t think our electricity ever gets to the place we sent it to, it is more like the volunteer fire departments each moving to the hole left behind when one is needed to cover a big fire, and our electricity is actually used right next door. Variable, erratic power sources will aggravate the problem of moving the electricity, just like another fire would cause the volunteer fire companies problems when covering for another station.
Solar, wind will “help” if used on a local limited bases, such as, running pumps for water treatment, storage, purification, etc. other locally consumable manufacturing process, or “off-grid.” The big, unrealized, problem is the integration. The core blog is just one aspect of the problem. There are many others. And, to our determent, just like one of my sons could only learn by making the mistake himself, the environmentalists will not accept the facts until we spent several billion dollars and the data shows that it creates more problems than it is worth.
There is actually a chart showing this to be true, Rich. It is a long URL:
http://books.google.com/books?id=9PSBHgqBpFYC&pg=PA252&lpg=PA252&dq=combined+cycle+heat+rate+
Kehlhofer&source=bl&ots=5pTlhHRYch&sig=BgPvy2COetgKOcoKka-j2kDAV4&hl=en&ei=TRQBTYKSIIWCsQ
PSp-yvCw&sa=X&oi=book_result&ct=result&resnum=5&sqi=2&ved=OCCwQ6AEwBA%23v=onepage&q&f=fals
e#V=onepage&q&f=false
Combined-Cycle Gas and Steam Turbine Power Plants
by Rolf Kehlhofer, See Page 211
Given the rule of thumb that CC is 50% more efficient than CT, the CC curve gets a 50% boost – or the CT maximum efficiency is 67% – take your pick. What I need is to understand the maximum ramping slopes of the most efficient CC units, and the (incremental) heat rate penalties at various slopes. With this info, we can improve Kent Hawkins model as well as make some high level statements proving the net fuel and emissions savings of wind energy. Ofcourse the empirical way is to convince PUCs and ISO/RTOs to make uniform dispatchability rules for all generator types in order to get interconnection approval. That rule would force a gas plant (or storage or hydro facility) to be located behind the main transformer at each wind facility. Now you have a competitive scenario – capacity resource vs. capacity resource. All in cost can be compared, and emissions can be measured. Checkmate.
As an electrical power systems engineer, I feel the need to clarify some points:
Wind turbines do not operate in the motoring regime. The control systems are structured such that they are always injecting positive real power into the system. Motoring, by definition, requires drawing real power from the grid. Wind turbines will never operate like this.
Fixed speed wind turbines, which are generally old models that are no longer being installed, did have problems requiring reactive power support. These older wind farms typically had capacitors installed nearby to provide this reactive power. New wind turbines have extensive power electronics that mostly avoid reactive power problems. Specifically, the doubly fed induction generators (DFIGs) that are installed on the majority of new turbines can control their reactive power over wide ranges of injections, both lagging and leading. Many plans for the next generation of wind generators call for converting all the power from the turbine thorough power electronic systems. Both DFIGs and these generators make wind turbines an asset to reactive power support from the grid operator’s perspective.
There are many reasons to question the grid impacts of wind power, but reactive power problems are not a major concern for modern wind turbines.
Rich, I think you need to brush up on your knowledge of power systems behavior. In an AC system, real power does not necessarily flow from higher voltage to lower voltage magnitude. Rather, real power flows from buses with higher voltage angles to lower voltage angles. Voltage magnitude is much more closely associated with reactive power injections.
For a better discussion on reactive power, I would recommend the Wikipedia page: http://en.wikipedia.org/wiki/Reactive_power or a power systems text, such as Power system Analysis and Design by Glover, Sarma and Overbye (chapter 6).
@EE – It may be a fable, but I have been told a story of at least on turbine that does motor quite regularly. It is a large turbine in the parking lot of a major wind turbine supplier factory that happens to be located right next to a major highway. Because of the turbine’s visibility to highway travelers, the company decided it would not be good to show people just how regularly the wind does not blow and the blades do not turn. To prevent their expensive “billboard” from becoming a negative, the marketing arm of the company told the engineers to make sure that the turbine never stopped turning. It is thus a motor more often than it is a generator.
Also, please correct me if I am wrong, but aren’t there some auxiliary systems in all large turbines that need to be kept operating even if the turbine itself is locked due to either high or low wind conditions? I am thinking of lubrication systems and, in some cases, heating systems to keep the turbine ready in case a breeze develops in the middle of icing conditions.
@Rod:
I don’t doubt there are some turbines that do operate as motors occasionally for when the bigwigs come to visit, or as advertisements. But clearly the vast majority of the turbines do not motor.
I know far more about the generators and power electronics on wind turbines (the high power components) than any other pieces of the turbines. There may very well be some auxiliary systems that must run even when the turbine is locked. But again, I don’t think this is an effective criticism of wind turbines. I can’t imagine that the auxiliary systems are more than a negligible portion of the turbine’s output. Other generation plants clearly have similar requirements for auxiliary power. Although I don’t have the numbers easily available, I would imagine that wind power’s auxiliary power requirements are significantly below those of other generation technologies.
@ Rich
I realize that my explanation was not geared toward someone without any training in electrical engineering. My apologies for that. Unfortunately, I do not have the time to put together a more accessible explanation, particularly since the normal “water in a system of pipes” analogy doesn’t really hold when dealing with reactive power.
Here’s my best attempt at answering your questions (again, my apologies that this isn’t more accessible).
1. No, creating VARs using power electronics does not require additional input power. Reactive power is related to the phase shift between the voltage and current waveforms. Power electronics allow you to inject current at whatever phase angle you like (within the current limitations of your power electronics), and thus control reactive power injection.
2. Modern power electronics can respond very rapidly (on the order of milliseconds or faster) when compared to the dynamics of wind speed (seconds). The control system can be configured to essentially immediately decrease the reactive power injection to respond to voltage increases, or conversely increase the reactive power injection to respond to voltage sags. Power electronics therefore act to stabilize the voltage magnitude in the grid. More sophisticated control systems are always under development, but these don’t have a large capital cost (control systems are implemented in relatively cheap digital chips). The power electronic devices themselves are made of semiconductors which have had a trend of increasing capability and decreasing costs for the last few decades. In any case, they don’t make up a very large portion of the total cost of a wind turbine.
3. Clearly, there are challenges to dealing with wind power. I do not want to downplay that at all. There are real costs to integrating large quantities of intermittent resources, and in many (most?) cases these costs are not borne by the wind turbine owners. However, the reactive power concerns you are voicing for wind power are not the main problem facing transmission engineers. The power electronics in modern wind turbines can in fact strengthen the reactive power support in a system. Again, that is not to say that a system with a large proportion of wind power is more stable overall. It probably isn’t. However, the reactive power support of a system with a large penetration of wind generators can be very strong.
4. No, I am in no way associated with wind power companies of any kind. I am an electrical power systems researcher at a large university. I am not specifically working on wind turbine research, but I do have some level of understanding of the technology they use.
For the record, I am a strong advocate for nuclear power. I don’t think we will achieve our national goals of moving toward energy independence, decreasing environmental impact, and providing globally competitive electricity prices without a strong and near term commitment to new nuclear plants (both large and small). Rod, I love reading your blog. One of the characteristics I really value is your commitment to engineering precision. Criticizing (modern) wind turbines for supposed reactive power issues is just not factual. There are plenty of reasons to criticize wind power; focus on those that are truly problems.
@EE – thank you for the detailed technical information about the ways that modern power electronics can eliminate the issues of reactor power from wind turbines.
Are all of the major wind turbine manufacturers using those kinds of controllers in their new machines?
When did these controllers enter into large scale use in the market?
(I read about the reactive power control issues in trade publications aimed at grid operators, so I am wondering if they were just whining or if the problem was real but getting fixed. If some of the lower cost turbines are not as sophisticated as others, perhaps that is an issue that needs to be discussed publicly so that wind farm developers are encouraged to take a step up. The situation you describe might be something like anti-lock breaking systems, which 10 years ago were only available on cars at the top of the automotive lines.)
@ Rod
The latest data I have, which is according to a Professor here, is from 2008. It shows that DFIG type machines with a significant level of power electronic capability were approximately 65% of new installations in 2008 (I believe this is based on new installed capacity). Machines that convert all power through power electronics are about 15% of new installations that year. Fixed speed turbines, which don’t use power electronics and potentially have issues with reactive power support, are about 20% of new installations. The installation of fixed speed turbines is on a downward trend, so that 20% has probably decreased by now. Unfortunately, I don’t have much data beyond that, or any data on different generations of wind turbine controllers.
I also talked last night to a friend who works at an ISO out east about this issue. He said that new turbine controllers typically have impressive capabilities, where they can essentially act as static var compensators (SVC) that help support reactive power. The problem they are having with these devices is that apparently some number of the wind turbines are not properly configured to take advantage of these capabilities. With the huge increase in wind installations, I wouldn’t be surprised if some of them were not properly configured. Perhaps this is what the the trade publications are complaining about? If that is the case, it is clearly not a technical problem but a knowledge problem.
@EE
The majority of the readers here do not have an EE degree, many do not have even have a BS degree, and thus need a simplified explanation. I thought I provided an adequate, yet simplified, explanation, and indicated that the windmill would not actually become a motor and turn into a fan. I am sure that you know that it would take several paragraphs to provide a good explanation of how AC power is actually moved from one area to another without creating even more questions.
Questions.
Is it not true that if the wind turbine is controlling VARs it is then using wind energy (fuel) to create these VARs and thus wasting fuel? Doesn’t this decrease the total efficiency (output) of the wind-farm and raise the total cost of wind generated electricity?
If all of these wind-farms are automatically controlling VARs, what happens when the wind suddenly increases and more power is dumped onto the grid in that area, while the dispatcher is trying to push electricity to a specific area? (Same question but decrease?) Doesn’t this create the need for more sophisticated control systems? How much will this equipment add to the total cost of my electricity?
Have you ever tried to control a system as complicated as the average electrical distribution system for the typical utility while some other system on the grid, with a mind of it’s own, is also controlling a portion of the system? Especially one that had a slight positive feedback? Have you ever had a system run out of control and cause un-necessary trips?
Do you sell/build wind-turbines or work in an electric utility dispatchers office?
EE: A few questions about your post, above:
1) How can WTs always be injecting positive, real power into the system when they are often not spinning?
2) How are control systems, yaw and pitch motors and blade and nacelle heaters run without a feed?
3) There are several publications for modern wind turbines that indicate they cannot black start, which, I believe, would be possible if “control systems (were) structured such that they are always injecting positive real power into the system.”
4) WRT reactive power, isn’t there an empirical, comparative value metric for this that can be used across all generator technologies? From your comments about reactive power, i am unable to put the value of wind turbine reactive power into perspective compared to a) conventional capacity resource reactive power as a percent of rated capacity or point in time output, or b) full time availability of reactive power relative to conventional sources. Is the reactive power portion of generation from WT held constant over the range of wind speeds needed required for generation?
No illusions about developing fission-powered aircraft?
For shame, Mr. Adams!
There’s certainly no technical reason why a nuclear-powered aircraft wouldn’t work: There’ve been workable mark-ups for nuclear-powered turbojets, turbofans, and in one particularly insane case, I dimly recall a closed-cycle nuclear turboshaft. I suspect, though, you were referring more to the difficulties of actually operating a nuclear-powered aircraft safely. No one, to my knowledge, has yet come up with a satisfactory answer: Though my favorite try was a Lockheed project from 1968, which proposed a 1.8GW reactor with 20′ of leaden rad-shielding built to endure a crash into a granite mountain at 400 knots without being compromised. I’d have loved to have been a fly on the wall for the trying to actually test such a claim. (The project was for a 1,120′-wingspan “airborne LHA”. We’re all probably better off that it quietly died in Lockheed’s notes, as trying to actually build such a thing would cause heads to explode.)
I clicked on your Brave New Climate link and was blown away by the comments. Mr. Goggin’s article came up against a brick wall of energy expertise, and was found wanting. Good read.
I just came across this link which discusses the high maintenance costs and shorter life spans for wind turbines. I had not seen some of these figures before.
http://www.petroleumworld.com/lag10090601.htm