Category Archives: Grid Integration

Turbulent Character

There are lots of unfortunate side-effects of wind turbines on the environment, including effects on the electrical grid to which they are attached.  It is no secret that the wind varies over time, and that variability translates to fluctuations in the electrical generation.  These fluctuations  occur on different time scales.  Some years are windier than others, as are seasons, days, hours, minutes and even seconds.  Over longer time scales these fluctuations are important because they necessitate having a reliable backup.  Over shorter time scales they effect the reliability of the grid and increase the workload on the other generators – leading to a number of researchers to posit that this additional workload ends up increasing emissions to the point where there are no net savings at all.  My personal perspective hasn’t changed in the years I’ve been doing this: we don’t know what the emissions savings from wind turbines are, potentially they are negligible, so why in the world are we spending billions of dollars when we don’t even know? Continue reading Turbulent Character

U Minn and Vestas Reality Check

A commenter recently pointed me to a University of Minnesota at Morris study  from 2008 that contained a wealth of interesting information about their one Vestas V82 1.65 mw turbine and how it has performed in 2006 through 2008.  The V82 is a rather common wind turbine, deployed in large numbers throughout the world.  Falmouth’s turbines are V82’s.  Thank you John.

Recently I’ve been working on the apparent decline of Capacity Factor over time and since this report appeared to have fairly granular hub wind speeds and production levels perhaps I could see if it suffered the same loss (somewhere between 1.5% and 2% per year) as has been noted in Ontario, Denmark and now Ireland.  The trend was in fact slightly downward, but the numbers weren’t consistent enough for just one turbine over just three years for me to put much confidence in that conclusion.  But during my examination of the report I came across a number of other interesting tidbits.

Electricity Production

In Vestas’ Life Cycle Assessment [backup link] of the V82 they “calculated”, per page 20, that at a Danish “typical” average wind speed of 7.38 m/s it would generate at a Capacity Factor of 40.8%, or an average of 673.2 kw out of its 1650 kw capacity.  I took UMinn’s daily average production and wind speed figures and produced the following clickable chart:

UMinn Reality vs Vestas Claims
UMinn actual production

The Vestas’ claim is represented by the yellow dot, which is clearly above the actual average of about 500kw – a decrease of 25%.  This is not trivial.  Adding to the exaggeration, below are the actual Capacity Factors for a selection of European countries – DK stands for Denmark.  So their “typical” and their “calculation” are each off by about 25%.  So instead of 40.8% we have 22.8%.

This exaggeration cannot be unintentional or uninformed.  The value of the turbine is slightly over half of what they claim.

Power Consumption

I have long been trying to nail down how much electricity a wind turbine consumes.  The wind industry seems quite reluctant to publish this.  As an example, in the V82 Life Cycle Assessment they lump all the manufacturing, operation, transportation etc. together into a 20-year lifetime total of 3392 mw-h, not willing to break it out.  Luckily, the UMinn’s reports include negative production numbers when the wind isn’t blowing enough to produce – about 3.5 m/s.  Each day they listed the minimum production, along with the minimum wind speed.  UMinn didn’t reveal the time increments, but fully 85% of the days during the 3 years had a negative-production period.  I graphed the results:

Daily minimum production vs wind speed
U Minn Minimum Wind Chart

The above chart shows the minimum productions plotted against the minimum wind speeds.  As you might expect, whenever the wind speed is above the 3.5 m/s cut-in speed the turbine starts producing, but not getting consistently into positive territory until about 4.5 m/s.  Notice the results when the wind doesn’t get above 3.5 m/s – typically there’s a MINUS 50kw of production.  This is power that must be supplied from the grid just to keep the turbine in business.  And 50kw seems to be what the turbine uses to stay alive in good weather.  In the winter it gets slightly higher – the highest negative numbers were in the 80 kw range.

So, finally, we have a measurement of just how much electricity they consume!  50 kw is quite a bit higher than my previous findings, which originated in industry statements and cash flow calculations.  Recall that the average Danish turbine produces about 376 kw (1650 * .228).  So a V82 operating in Denmark consumes roughly 13% of what it produces.  No wonder they want to keep this quiet.

I think the reason it is so high for the V82 is that the generator must use an electromagnet, compared with newer turbines that use rare-earth-based “super” permanent magnets.  In their Life Cycle Assessment for the V82 they mention the iron and copper in the generator but do not mention any rare earths.

Wind Shear

The wind gets stronger the higher above the ground you get, generally in a logarithmic manner.  The rate at which it gets stronger is embodied in the Wind Shear Exponent, which varies from 0.1 over water to 0.4 in urban areas.  UMinn’s exponent was 0.244, which is typical of a rural landscape with trees and small buildings.  UMinn produced the picture below which graphically represents how the wind shear affects the wind turbine.

U Minn wind shear
U Minn Wind Shear

Note that at the bottom of the rotors the average wind speed is 6 m/s, while at the top it is over 8 m/s.  This is a big difference in terms of the forces, which flex the blades every rotation and no doubt contribute to their wear.  This also contributes to noise generation, and may be responsible for the very annoying “thumping” that wind turbines sometimes produce.

Wolfe on the Ontario Grid

Denise Wolfe lives on Amherst Island (along with John Harrison and me, part time) and really knows how to do research and even better how to summarize it.  As part of her efforts to convince the powers-that-be to stop the project on Amherst, she prepared a summary of what is currently known about the effects of wind turbines on Ontario’s grid.  It is brief (6 pages) and to the point, and is totally accurate.  If you need a good summary of what a mess wind energy has made of the Ontario grid this is excellent.

Links

Denise Wolfe, Ontario Fact Sheet

The OSPE Submission

The Palmer Submission

Palmer’s Submission to the Submission

This is part #2 of a 2-part posting.  Part #1 covers the original OSPE Submission.

William Palmer is a Professional Engineer who accepted an early leave from paid employment to be able to apply his skills and knowledge (he maintains his professional credentials) to issues facing his neighbours.   Last month the OSPE (Ontario Society of Profession Engineers) issued a draft submission for the Ontario Ministry of Energy with some recommendations on how to handle Ontario’s growing Surplus Base load Generation (SBG) problem.  The OSPE draft called for submissions on the draft and Bill answered their call.  His submission is a very powerfully written indictment of Ontario’s wind energy program and its oversight. Continue reading Palmer’s Submission to the Submission

OSPE and the SBG Submission

This is the first of two inter-related postings – William Palmer’s submission to the submission is part #2.

The Ontario Society of Professional Engineers (OSPE) has a membership of over 9,000 professional engineers working in Ontario.  It provides a number of services for its members (job searches, resumes, conferences and so on) and also serves as an advocate for the interests of its members before regulatory bodies  and the Ontario government.  In December of 2011 it released a draft of a document that it plans to submit to the Ontario MOE with recommendations on what the Ministry can do to lessen the problems the Ontario grid is having with something called Surplus Base load Generation (SBG).  Being an advocacy group, it is not doing this out of any charitable impulse.  Rather, the SBG problems are already significant and promise to become much larger, which “…negatively affects our member engineers who are dependent on the health of various industries that use large quantities of electricity.”  The OSPE does not consist of “anti-wind cranks” (in the famous words of lobbyist Gordon Edge, describing Civitas).  They have historically supported wind energy.  When engineers, especially those in a position to be fully informed on an issue, are worried about the consequences then I’m worried too.  Too bad the current Minister of Energy, Chris Bentley, doesn’t seem to be. Continue reading OSPE and the SBG Submission

Maturity

In many pro-and-anti-wind energy discussions the topic of subsidies to the wind energy industry comes up.  Just for the record, those subsidies are now larger even in absolute terms (not to mention relative terms) than subsidies for the fossil fuel industries.  The usual response is that all new industries need subsidies.  The underlying theme is that wind energy is in its infancy and has lots of room to mature.

This infancytheme was thrown a monkey wrench when DOE secretary Chu mentioned that onshore wind is already mature.  So is wind infantile or mature?  One indication of which it is might be to look at the efficiency of today’s wind turbines at converting the dynamic energy of the wind into electricity.

It is surprisingly easy to calculate the amount of energy available from a given amount of wind moving through the diameter of a turbines blades.  You multiply the density of the air, it’s speed (cubed) and the swept area, divide by two and voila you’ve got the watts available.  One problem is that it is impossible to extract all the energy from the wind – you’d have to stop the wind to do so, but this wouldn’t allow any new wind to pass through the swept area.  A clever man named Betz (among others) figured out the maximum amount you could extract (now known as the Betz limit), which turns out to be about 59%.

So how close do modern turbines get to the Betz limit?  If they are pretty close then I think it is safe to call the industry mature.  The only way to extract more energy is to go higher and larger, and at some point this becomes self-defeating from both economic and engineering perspectives.  I cranked up a spreadsheet where I calculated the potential energy vs. what turbines are rated at and it produced the following chart (which is clickable to enlarge, thank goodness).The turbine I used for this chart is the Vestas low-wind-speed 1.8MW turbine that is proposed for Amherst Island, but the spreadsheet is set up to allow other turbines to be modeled.  The spreadsheet itself (an xls) is available for the asking.  The most important column is labeled “%age of Betz” which shows how close that turbine comes to perfection.  The subsequent column shows more realistic numbers that take into account the necessary generation/rectification/inversion/sychronization that must take place in a real turbine trying to join a real grid – I used a fixed 5% loss, which I think is probably low.  Over a large percentage of the time (as shown by the far right column) the efficiency of the turbine is quite close to the Betz limit.  I’m not sure how much more maturity we can expect out of turbine design.

Over all wind speeds the efficiency of this model is about 50% of the Betz limit, so perhaps there is some potential design that could capture all the energy at all wind speeds.  Such a design would likely require a shape-changing blade, made of materials that do not currently exist and controlled by a means that doesn’t exist either.  If wind turbines, at 50% of their potential efficiency, are not mature then I think it is hard to claim that coal plants, at 45% of their potential efficiency, are.

The influential 20% by 2030 report partly justifies the extraordinary investments in wind energy by estimating that wind turbines over time will increase their capacity factors from a current 30% to an anticipated 45%.  That would correspond to an increase in efficiency from about 75% of what is possible to 112%.  Too bad all those PhD’s at the DOE didn’t have access to my spreadsheet, or to an earlier posting of mine.

Wind energy supporters have every right to be nervous about all the subsidies flowing their way, so they’ll say whatever they can to keep them coming.  But the infancy theme is, like so much of what they say, simply not defensible.

Is there an echo in here?

I don’t take a lot of pleasure out of seeing what I’ve written confirmed, having the “I told you so” moment, just as I don’t take a lot of pleasure out of being the bearer of bad news about wind energy.  But every now and then some industry insider confirms what I’ve been saying and at least that lets me know I’m not totally divorced from reality – that my wits are at least marginally intact.  And I do enjoy having that confirmation.

At the American Public Power Association conference last week in Washington one Kevin Gaden, who is director of a power consortium in Nebraska, made a speech, that from the sounds of it, could have been based on my writings.  Except, of course, it was based on his experience in the field.

Link to The Reality of Wind Power [backup link].  Compare that to my Emissions Savings Summary page.

The Last Word on Geographical Spread?

Everyone concedes that the output from wind generators is highly volatile – being the cube of the wind speed and all.  Proponents try to minimize the effects of that variability by either inventing storage technology that doesn’t exist or by claiming the “wind always blows somewhere” and by building a “super grid” we can move the energy from wherever it is being generated to wherever it is being used.  Their ideas on geographical spread seem intuitively correct, but nature usually reserves her greatest punishments for those who think they can intuit her rules without looking at reality.  As always, let’s look at the actual numbers. Continue reading The Last Word on Geographical Spread?

Some Numbers From the UK

I’m a numbers and evidence kind of guy, so when a report comes out with actual measurements I give it a great deal more weight than mere speculation.  In the UK the Muir Trust sponsored a report [backup link] that looked at the UK’s actual wind production numbers and used them to see how the reality stacked up against the hype coming from the wind industry and their government allies.  As you can imagine, there wasn’t much of a stack up at all.  Continue reading Some Numbers From the UK

More on Ontario’s Exports

After my first posting on Ontario’s Exports, where I asked why Ontario was still burning coal when every bit of it was being exported, I received a note from Donald Jones, who has done a lot of digging into the details of Ontario’s operation.  Here’s his letter, which gives you an idea of just how screwed up Ontario’s electricity system is, and why renewable energy (and wind turbines specifically) are making the problems worse. Continue reading More on Ontario’s Exports

Ontario’s Exports

Ontario ministers (i.e. Duguid and Wilkerson) have continued to justify forcing the installation of wind turbine projects into communities that don’t want them by claiming the greater good is being served – specifically that wind energy allows Ontario to burn less coal, thus preventing the early deaths of hundreds of people due to asthma etc.  Their “hundreds of people” claim is highly dubious in the first place – see the research by Ross McKitrick.  In the second place, as I have shown over and over again, there is no connection between wind energy production and lower coal production.

As always, me being me, I continued to wonder where all this wind energy went. The most obvious answer is that it was exported, at great loss, to Ontario’s neighbors.  Certainly Ontario’s exports in almost all cases exceed whatever the wind is producing.  But when I ran the numbers, the relationship between wind production and exports was roughly the same as between wind and coal – which is to say, almost non-existent.  However, the relative shapes of the two sets of curves was close enough that I started wondering what the relationship of coal production was to exports.  And since I’m writing this posting, you know I found something interesting. Continue reading Ontario’s Exports

Wind and Risk to the Grid

Donald Jones, P.E., has written periodically on different aspects of the Ontario grid.  This latest effort analyzed the recently-released Long Term Energy Plan and finds that there isn’t enough operating reserve to accommodate all the wind energy that the plan envisions.  I’ve written similar analyses myself, but Donald does a better job of it than I do.

Jones, More Wind Means More Risk to the Ontario Grid

Ontario’s Record Day Examined

For the 48 hours on Tuesday and Wednesday, October 26-27, 2010 Ontario’s wind projects generated a record amount of energy.  A massive record-setting storm system moved mostly to the south, providing Ontario with just about the best two days of production that could feasibly be expected.  Not surprisingly CanWEA crowed about it [backup link], and even the wire services [backup link] picked up on it.  As always, me being me, I took a closer look to see just how wonderful these days were for Ontario’s electric users.  And after looking at it, I’m not so sure I’d like to have many more record days. Continue reading Ontario’s Record Day Examined

Surplus Baseload Generation

In an earlier post, Emissions Savings Details, down in the “And Worser” section, I mentioned that between the not-entirely-dispatchable CHP plants and the entirely-not-dispatchable wind projects, Ontario has so much surplus generation at night that they end up paying other people to take it off their hands.  This is called Surplus Baseload Generation, and as the number of CHP and wind generators continues to grow in Ontario’s attempt to shut down its last coal generators, it is becoming more common.  Ontario’s IESO, the grid operator, now publishes a daily report that forecasts how big these surpluses will be.  Take a look at a recent report – these numbers are BIG, and they seem to occur almost every night, at least during low-usage times of the year. Continue reading Surplus Baseload Generation

The Super Grid Might Work After All

One of the problems with wind power is that the output from all the projects within an area tend to produce power at the same time.  Proponents claim that if you make the area big enough, and interconnected enough with transmission lines big enough the “wind always blows somewhere”.  But how big is big enough?  We know that a diameter of 250 miles is not big enough, as evidenced by the variability of the output from all of the projects within both the Ontario and Bonneville areas, as shown below.  What is also left out of this discussion is the environmental and financial costs of those lines – which must be sized to handle the capacity of all the connectible wind projects, but which on average will carry only 25% or so of that capacity.

Continue reading The Super Grid Might Work After All

Paying for Nothing

In my Emissions Savings Details posting I mentioned the problems when there is too much wind energy (which is, after all, uncontrollable) being produced during periods (typically overnight) of low usage.  In Ontario, they solved the problem, if you can call this a solution, by taking a CO2-free nuclear generator offline.  In the UK, they solve the problem by telling the wind projects to turn off their production.  That, in itself, is no big deal – it is routine to tell the producers to shut their production down to balance the grid.  The big deal is that in spite of no production, the projects still get paid their very high subsidized rates even when they don’t produce.

Continue reading Paying for Nothing

Bonneville

The Bonneville Power Authority (BPA) is a Federal agency that provides electric generation and transmission for the Pacific Northwest.  It controls the Federally-owned dams in the Columbia River basin, one nuclear reactor at Hanford, some fossil generation and now wind.  It is one of the largest hydroelectric operators in the world, controlling some iconic dams – like Bonneville, Grand Coulee and John Day.  The large amount of hydro under its control, the political control the government has over it, the access to Federal money it has, the lack of needing to make a profit – all these should make the BPA the very best place in North America to implement wind energy.  If wind isn’t effective here, it won’t be effective anywhere.  Presently BPA has about 2700MW of wind capacity, and I thought it would be useful to examine their experience to see how well they are doing.  What I found was interesting – not so much because of their experiences (which are typical of other operators) but because of their willingness to publish wind production data that is hard to obtain elsewhere.

Continue reading Bonneville

Comments on FERC Rules

The Federal Energy Regulatory Commission has been working on how to best accommodate the recent upsurge in uncontrollable renewable energy – like wind and solar.  They asked for public comments relative to easing the integration  rules for “Variable Energy Resources”.  Lisa Linowes, of Industrial Wind Action Group, and William Short submitted a response.  It is 9 double-spaced pages long and is well worth reading to give you a feel for the issues.

Linowes and Smith Submission

Meeting Peak Capacity

The peak demand for electricity in most places is in the summer, and unfortunately the wind tends to blow less at that time. Given that especially during summer there is a good chance wind will contribute essentially nothing to the grid, it becomes necessary to have other means of generation available at all times. Wind will not displace other generation methods. We will still need enough nuclear, coal, hydro and gas to meet the peak, regardless if wind is in the mix or not. There is no documented case of wind energy leading to the shutdown of any tradition generation.  The best case that wind can make is that building natural gas plants, being the only generation that compliments the variability of wind, may at some point allow some i.e. coal plants to be shut down.  But even that weak gruel hasn’t been documented anywhere, not even in Denmark. Continue reading Meeting Peak Capacity