Archive for wind

Wind Power: Cool Breeze or Hot Sirocco?

Jamie Bull brought to my attention a paper saying that land based wind turbines are likely to create a small degree of earth surface warming.

Jamie was concerned that there might not be a net surface cooling, even once the effects of reduced greenhouse gas emissions were taken into account. He did some calculations, and showed that the net effect of wind power on surface temperatures was still strongly negative.

He need not have worried. An understanding of the mechanism of this surface heating, and the conservation of energy make it clear that the surface heating effect of wind is smaller than the surface heating effect of thermal electricity generation such as coal, gas, nuclear, and Concentrating Solar Power (CSP) on a per kWh basis.

Conservation of energy tells us that all the energy in wind is eventually dissipated by friction, creating heat. The effect of wind turbines is to take some of this energy that might have become heat in the atmosphere, and create electricity, which will eventually become heat on the earth’s surface, and some will become heat in the turbine itself.

The net heat added to the Earth by wind turbines is zero: heat that would have been created in the atmosphere is now created on the surface instead, and the net effect is zero.

Now consider thermal electricity generation. When a fossil fuel is burned, or when a nuclear power plant or CSP plant makes steam, heat is either created from a fuel or captured from the sun, reducing the amount that would reflect back into space. All this heat is dissipated at some point near the earth’s surface, creating more surface warming than wind power, and also creating net warming where wind power creates none.

The direct surface heating effect from wind is likely to be only a fraction of the direct surface heating effect of thermal electricity, even before the effects of greenhouse gasses are accounted for.

Solar PV and Solar CSP capture heat from the sun that might otherwise reflected into the atmosphere, so more precise calculations are probably needed to determine if their net effect is negative before the effects of greenhouse gasses, but wind is clearly cool by any thermometer.

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Better Software Enables Better Wind Integration

A year ago, I wrote an article about the Dumb Grid, complaining that the reason that many utilities find wind power so hard to integrate is because they aren’t using any brains. I used the infamous Feb 2008 incident when wind power in Texas dropped right as demand picked up because of a cold front to make my case: Both the rise in demand and the drop in wind power were predictable consequences of the cold front, but the ERCOT controllers were not using that weather information in their dispatch planning. Hence, the problem was not wind power or even the cold front: it was failure to use the available information.

Fortunately, things are much better today. There’s an excellent article on Power-Gen Worldwide about the Texas electric grid’s control center two years later. Here’s an excerpt about how they deal with wind variability today:

    The wind resource is more manageable now that ERCOT has wind resource forecasting software at its disposal. [...]

    ERCOT has begun using forecasting tools from AWS Truewind to help it manage wind energy resources. In the coming days ERCOT will begin using a ramping tool, from the same vendor, to improve its forecasting of wind resource ramping events. Just a week before our visit, the AWS Truewind software–operating in a test mode–predicted a 2,000 MW drop in wind resource followed 15 minutes later by a 2,000MW recovery. The predicted ramp event matched the actual event almost perfectly.

    Joel Mickey told me that ERCOT is happy to dispatch as much wind energy as is available.

Thanks to Micheal Giberson over at Knowledge Problem for bringing this article to my attention.

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About 3x as Much Wind Power Available at 80m than at 50m hub heights

A new National Renewable Energy Laboratory (NREL) study, taller wind turbines can produce more power.

This is no surprise to anyone. Trees and other objects on the ground slow the wind, and as you get higher, you enter the region of smooth laminar flow where more energy is available. Laminar flow starts at about 50m.

A wind turbine with a hub height of 50m will have half its swept area above 50m. A wind turbine with 50m blades and a hub height of 80m. See my drawing:

What is interesting is that we may need to revise all our assumptions about how much wind is available for electric power. In Colorado, NREL found 3x as much wind potential at 80m than a previous Colorado study using the 50m hub height assumption. After all, not only is there more swept in the laminar flow, but there are more areas where tall wind turbines would have the 30% minimum capacity factor NREL assumes is enough to make them economic.

Here’s a graph showing the increase in capacity factors going from 80m to 100m hub height.

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Wind Power and Wind Speed

I received serious skepticism to my idea that wind turbines could significantly slow the wind speed on the Great Plains. One of the criticisms came from an atmospheric scientist I asked to weigh in on the matter. The problem is, I did not find either of their arguments convincing, although I concede Daniel knows more about it than I do.

In responding to them, I came up with an approach for calculating the total power of the wind in the Great Plains. Wind is caused by differences in temperature and pressure as a result of uneven solar heating. Hence the total energy of the wind is a small fraction of the total solar flux. I’m guessing that the amount of solar flux that is actually converted into wind energy is below 1%, probably far below that, but I’ll use 1% until someone gives me a better number.

The Great Plains is 1.4 millions square miles in area, including parts in Canada and Mexico. The average solar flux is about 4 MWh/day/m2 (using numbers for Des Moines, IA.) There are 2.6 million square meters per square mile, making the total solar flux on the Great Plains about 14 trillion MWh/day. Using my 1% conversion efficiency into wind, and 24h in a day, we get total average wind power on the great Plains of 6,000 million MW. That energy is currently absorbed by objects on the ground and internal frictional losses in the air. To create significant wind speed drops, a significant fraction of that 6,000 million MW would have to be absorbed by wind turbines.

In my previous article, I used another approach to calculate that 1 million MW of wind turbines would be enough to significantly slow the wind on the Great Plains. Hence, unless my 1% solar-to-wind conversion efficiency is too high by three orders of magnitude, it looks like the skeptics were right.

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Wind Power and Soil

I recently had the somewhat questionable pleasure of driving across most of the Great Plains.  It has been over a decade since I last did a long distance drive across the Plains, and a new feature is starting to pop up: Wind turbines.  Sometimes in ones and twos, sometimes by the tens or hundreds.  I may be biased, but I find modern wind turbines to be among the most beautiful built structures in the world.  They have a slow, graceful motion that belies their Brobdingnagian scale.  They were particularly beautiful on a foggy evening driving as I drove through a wind farm near dusk, when I could see only the bottom half of the giant blades as they swept gracefully down out of the mist in a slow motion appearing and disappearing act.

The other feature of the generally broad and open landscape were lines of trees, sometimes bordering the interstate, and sometimes bordering fields.  I recall from a US history class in high school that these wind breaks were planted in response to the 1930′s dust bowl.  A little web research led me to the Shelterbelt Project, which seems to be what I recalled (somewhat inaccurately) from high school:

Established by President Franklin D. Roosevelt under executive order on
July 21, 1934, the Shelterbelt Project provided for a tree barrier one hundred miles wide extending twelve hundred miles north to south from the Canadian border through the Texas panhandle. It was designed to
reduce wind velocity, which had occasioned severe soil erosion across the Midwest and dust storms to the eastern seaboard.

In some ways, the Shelterbelt project can be seen as an early experiment in geoengineering. I sincerely hope that any future projects are so successful and benign.

Wind turbines, too, reduce wind velocity.  After all, a wind turbine’s function is to take wind energy, and convert it to electricity.  This led me to wonder just how many turbines would it take on the Great Plains to significantly lower the average wind speed in the region?

According to FTExploring, a wind turbine can extract about 35% of the wind energy passing through the swept area of its blades.  A typical 2.5 MW wind turbine from General Electric (GE) has a rotor diameter of 100m.  To get a ball-park figure, imagine two rows of GE 2.5MW turbines were installed from north to south along the Shelterbelt project (1200 miles) with rotor blade tips inches apart.  If the two lines were offset, wind blowing from east to west or west to east would have to pass through one or two rotors, losing 35% to 58% of its energy along the way, and exiting the back of the turbines 15% to 25% slower.

Such a double row of turbines would require about 386,000 turbines, or about 1 million MW of wind.  So, according to this back-of-the-envelope calculation, 1 million MW of wind installed in the Great Plains (even if not installed in a north-south line) should be enough to noticeably decrease the overall wind speeds in the region, and not only reduce soil loss from wind, but also reduce the cost effectiveness of installing more turbines.  Assuming a 35% capacity factor, this equates to about 3,066 million MWh.  In 2008, the US produced 4,119 million MWh of electricity, so 1 million MW of wind represents about a 75% of electricity production from wind in the Great Plains.  Even if there were sufficient transmission to distribute the power across the country, and geographic diversity greatly moderated the the overall variability of wind, such high penetrations would be impossible without prohibitive investments in electricity storage. 

With current storage technology, a greatly enhanced national grid, and a full roll out of smart grid technology used to better match demand to supply, I would guess that the upper limit for wind penetration would still be only 50% (and considerably lower if any of these things fail to materialize, especially the diversifying benefits of a robust national grid.)   This upper limit (and the fact that only a fraction of wind power is likely to be generated on the Great Plains) means that we’re probably unlikely to need to cut down any trees on the Great Plains in the hope of increasing the wind output of out turbines.

The United States had a cumulative 35,000 MW of wind installed by the end of 2009 (about 3.6% national penetration using the numbers above) so we’re still a long way from slowing the wind significantly on the Great Plains, or anywhere else.

I wonder if farmers who lease some of their land to wind farms notice any local slowing of the wind?  Is that a positive externality worth accounting for?

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Is There a Tradeoff Between Economics and the Environment?

Tom Konrad Ph.D.

California’s RETI process lends insight into the near-term prospects of Solar, Wind, Geothermal, and Biomass.  

In September, California’s Renewable Energy Transmission Initiative (RETI) released their Phase 2A report, which outlined potential transmission corridors to collect renewable energy from Competitive Renewable Energy Zones (CREZ) that had been identified in previous phases.  As part of Phase 2A, they also screened each CREZ for environmental impact, and the potential difficulty of obtaining land for renewable energy development.  

I previously looked at the results from Phase 1A and gained some insight into the cost of renewable energy technologies.  However, what renewable energy projects actually get built has to do with a lot more than just economics.  If it raises too many environmental concerns, such as infringing on endangered Mojave Ground Squirrel habitat, it isn’t going to get built.

Drawing on the spreadsheet "Supplemental Materials, CREZ Data" I put together the following charts, graphing the economics of each type of renewable energy in each CREZ against the expected environmental impact of that CREZ.  

Each circle represents one type of renewable energy at one of 35 CREZs.  Concentric circles in different colors appear where a single CREZ offers multiple types of renewable energy development.  The only difference between the two graphs is the size of the circles.  In the first graph, circle sizes represent the potential annual energy production (GWh/yr) of a CREZ, while circle sizes in the second shows power rating (MW.)  Geothermal and Biomass resources are relatively larger in the first graph because these are typically baseload technologies generating electricity near peak capacity all the time, while solar and wind are variable.

The cluster of circles in the middle right represent resources outside California: they were not rated for environmental concerns, so I assigned them an arbitrary value in the middle of the range in order to display them on the charts.

Economic/Environmental Tradeoff?

I found it surprising that there is little evidence of a tradeoff between economic viability of CREZ’s and environmental impact.  In fact, the circles in the graphs above are generally clustered along a line from the lower left (high environmental impact, bad economics) to the upper right (little environmental impact, good economics).  A tradeoff between economic viability and environmental concerns would manifest itself in a clustering along a line from the upper left (bad economics, little environmental impact) to the lower right (good economics, large environmental impact.)

Considering these four major renewable energy technologies, as they might be deployed in California, there is no real tradeoff between economics and the environment.  The best economics coincide with the least environmental impact.  If we were to include energy efficiency in the analysis, the trend would be even more pronounced: energy efficiency has the best economic profile of all, yet avoids the use of energy and hence does less harm to the environment.

The exception here is biomass.  The small green dots don’t show a pronounced trend in any direction, meaning that there may be some tradeoff for biomass.  Such a tradeoff would not be surprising, because harvesting plant matter on a large scale is bound to have significant ecosystem impacts.  Note that Biomass here does not include such technologies as waste to energy, which can be environmentally benign, or even an improvement compared to land filling.  In this study, the biomass in remote regions that do not yet have transmission, since lack of sufficient transmission was one of the requirements to be a CREZ.

With clean energy, it may actually be possible to do well while doing good.

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The Algonquin Power Income Fund

I recommended the Algonquin Power Income Fund as a renewable energy income investment back in January, and as part of my ten clean energy picks for 2009.

Since then, both the stock and the ten picks have been doing well in comparison to the market, but Algonquin has entered into a couple deals, while I look into in a recent update on the Algonquin Power Income Fund.

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Two Renewable Energy Penny Stocks

I asked my readers at Alternative Energy Stocks what companies they wanted to know more about, and the two most requested were a transmission and wind company (CPTC.OB), and a company looking to make oil for biodiesel from algae (PSUD.PK)

Click through the links to read the results of my research.

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Transmission Stocks.. not exciting enough?

My AltEnergyStocks column this week is about investment opportunities in transmission, but to judge by the comments, readers are much more interested in direct investment in wind.

This is not particularly surprising to me… electric transmission is both complex and boring. It’s also absolutely necessary for our transition to a sustainable energy economy. As a contrarian, the lack of interest in my readers makes me more bullish; I love sectors with great prospects that no one is interested in talking about (or buying) yet.

An interesting parallel is my article on the polysilicon industry, which I wrote last July. At the time, only my regular readers read it, but in the last few months, now that the companies involved have risen another 50-100%, it’s consistently one of my most popular, despite the fact that there’s a good chance that the silicon supply crunch may soon ease up.

I wonder how many people will be reading my transmission column eight months from now?

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Inverter Stocks: A Backdoor to Solar and Wind

My column on this week is about the companies that make the inverters which transform the DC or wild AC current produced by solar panels and wind turbines (respectively) into the type of AC power used by the grid. It begins:

    Whenever there is a gold rush, the people who make the real money are seldom the gold miners, but rather the suppliers to the miners that come home with the lion’s share of the profits. This is not because there is not an incredible amount of money to be made in mining gold, but because the nature of a gold rush is that too many optimistic miners are encouraged by the early profits of a few to rush to pursue too few opportunities.

    To many, the rush into solar stocks seems to be just that sort of gold rush. The boom in solar IPOs certainly reminds me of the type of feeding frenzy in which incautious investors are likely to get burned. And we are also seeing some other signs of rampant speculation, where investors are buying poorly managed (or even dishonest) companies with almost the same fervor of well managed ones. There’s little doubt that the future is bright for solar power, but picking solar companies that are going to survive and thrive in that bright future is becoming increasingly difficult in an increasingly crowded field.

    In a gold rush like this one it makes more sense to look at the suppliers.

Click here to read the rest of the article.

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Visual Comparison of Electricity Generation Technologies

I just put together a couple graphs for a talk I’m giving on Monday to give people a visual feel of the various technologies for generating electricity.  These come with a gigantic caveat: the numbers are far from precise.

With changing technologies, it’s impossible to represent any of this with a single number anyway.  I’m trying to show how the technologies compare to each other, and I used four parameters:

  • Cost ($/MWh),
  • Availability (better the closer the profile of the technology matches a normal demand curve (wind is bad, baseload is okay, dispatchable is best, solar),
  • Emissions (and I count waste storage when it comes to nuclear),
  • Bubble sizes represent the size and durability of the resource (I’ve tried to combine in one number how much power we can get from the resource, but also how long supplies of fuel will last.) 

In both charts, the “best” technologies are in the upper left (low cost, low emissions, and available when we need them.)

I know that I’m going to upset a lot of people because I was too harsh with their favorite technology, so feel free and comment on the numbers I’m using, but also please provide references for where you get your numbers.  Most of these are off the top of my head, so their accuracy is admittedly questionable.   Here are the numbers I used to make the graphs.

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Holistic Approaches to Energy Problems

H. L. Mencken said, “For every human problem, there is a neat, simple solution; and it is always wrong.”  When it comes to solving the problems of peak oil and global warming, I also think that the loudest barking is up the wrong tree.  We look for the quick fix, trying to find a substitute energy source that allows us to change the way we do things little as possible, when the real problem is actually what we’re doing, not how we’re doing it.   We need holistic solutions, not quick fixes.

Too abstract?  Here are some concrete examples:

 Problem: Peak Oil

Quick fixes: Ethanol and slight increases in vehicle efficiency standards.

Holistic solutions: Change our driving culture and infrastructure, by changing the way car use is priced from fixed charges to a per mile basis (“Pay as you drive”).   Removing subsidies to use cars when other forms of transport are available, and redesigning our cities to make them easier to get around on foot, bike, and public transport.  Like other holistic solution, all these steps increase safety and reduce congestion, reduce obesity and associated health problems, as well as reducing the use of gasoline.

Problem: Wind and Solar are intermittent resources, but coal produces too much CO2 and natural gas prices are rising rapidly.

Quick Fixes: Nuclear power and “Clean” Coal.

Holistic Solutions: Shift our demand for electricity to times when it is available, by using time of use pricing, energy storage and demand alignment, and distributed energy storage such as plug in hybrid vehicles.

Investing opportunities:On thing that’s striking about these examples is it’s much easier to find investment opportunities in the quick fixes than in the holitistic solutions.  To invest in ethanol, you can just buy ADM or one of the multitude of ethanol stocks that have been going public recently, but I have yet to come up with a satisfactory way to invest in better urban planning (except buy a house in a walkable community, which is something I’m planning on doing this summer.   Stapleton is the community.  I currently live there, but I’ve been renting and waiting for the end of the housing bubble.  I actually don’t think that housing is going to go up again any time soon, but I’m tired of waiting.) 

The investment landscape is a little better when it comes to energy management.  Itron and Siemens both have divisions that help utilities manage their grids better, and there are many battery and other energy storage companies to choose from.  Still, it’s a lot harder to pick through battery companies than to just buy a nuclear powered utility or uranium miner.

Holistic solutions, by their nature, have weak boundaries… the benefits tend to be diffuse, and spread over society as a whole, so it is difficult to charge fairly for them.  This, I think, is why there are so few companies pursuing them when they can pursue a quick fix that they can charge for up front.  

Companies have an obligation to their shareholders to make money.  It’s our job, as human beings, to work towards regulations that make it easier for companies to make money with holistic solutions that actually solve the problem than it is to make money with quick fixes that just cover the problem up.

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Vestas coming to Northern Colorado

It now looks likely that Vestas, the world’s largest wind turbine manufacturer will build a blade manufacturing plant in Nortern Colorado, near Windsor.  I’d guess that some of the factors that made Danish Vestas consider locating here are:

  1. The proximity to NREL’s Wind Technology Center for turbine testing.
  2. Amendment 37, which will require large investments in wind farms in Colorado.
  3. The State’s central location, making it easy to ship blades anywhere in North America.
  4. Political support for wind, especially from newly elected Bill Ritter and the Democratically controlled state legislature.
  5. Colorado’s excellent wind resource.

The 500 high-paying jobs will be ones wind advocates can point to when talking about the benefits of renewable resources over fossil fuels.


It’s official. According to this follow-up article in the Rocky Mountian News, transport was indeed crucial to winning the bid. In particular, they wanted a site with rail service.

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Secrets of the Utility Mind

I feel that many of us renewable energy activists do not understand how utility planners think.  To us, we see wind as cheap electricity, but to them it is the Predator (of movie fame), something that looks benign and friendly, but at any moment will wreak havoc on their grid by turning off unpredictably.

In order to have a constructive conversation with utility planners, I think it is important to understand their point of view.  This is my attempt to do that, with the hope by doing so, we will be able to engage with them more productively.

These are what I see as the underlying principles that shape the utility planning process:

There is no God but Reliability, and Least-Cost is his prophet.

Or, put another way,

The Holy Trinity of electric resource planning: The Baseload, The Cost, and the Holy Reliability.

I use the religious references to make a point: reliability is a religion for utility planners, and people become defensive and angry when you threaten their religion.   If we want to work with the utilities, we need to address their real concerns about intermittent renewable resources such as wind and solar.  And we have to work with utilities if we are going to modernize the way we get and use electricity. 

How do we deal with people committed to this religion?  By taking their concerns seriously, and helping them find solutions.   In short, when we hear “Wind is so unreliable,” we should say “That’s true.   Here are some ways we can take advantage of the benefits of wind without compromising the integrity of the grid.  We can be allies in getting regulators to approve rates that allow utilities to get a fair rate of return on these measures that improve reliability, while also allowing more wind onto the grid without impacting reliability.”

Why do we expect them to listen?  Because they already have and have to work to deal with a problem that is very similar to unpredictable generation from wind: unpredictable loads.  People and companies turn appliances and whole factories on and off unpredictably, and never once do they think about calling up the utility first to let them know that they should have the necessary capacity ready at the appropriate time.  Instead, we as consumers just flip a switch, and never expect that the lights won’t come on because there is not enough capacity.  If they don’t we get angry.

How do utilities accomplish this seemingly impossible feat of matching supply to capricious demand?  They do it with extensive load modelling, so that they can predict approximately how much  load will be on the system at any given time with a fair degree of accuracy, and by maintaining “Spinning reserves,” which are basically generators which are already up an running under very low power (hence “spinning”) and turning in synchronization with the current of the grid, like a non-hybrid car sitting at idle.

When there is a sudden increase in the necessary load, they can then increase the power produced from the spinning reserves almost instantaneously, like the motorist of our metaphor starting up when a light turns green.

There are many types of generation that can be used as spinning reserves, not only gas turbines.  Hydroelectric dams can work well this way, and can agreements with neighboring utilities to supply power when it is needed, on the theory that two different utilities will not have the same load patterns, and so both utilities can gain by trading power back and forth as needed.

There are many proposals circulating to increase grid reliability and ability to accept more intermittent resources.   As is usual in complex problems, there is no one solution, and in this case it will always be a combination of many of these (and some I don’t know about… please leave comments if you have ideas I’ve left out), and the mix will vary widely depending on the unique situation of any particular utility.

  1. More transmission.  Wind not only needs massive new transmission capacity to get the electricity from windy rural areas to the places that need power, but a more robust grid means that widely dispersed wind farms can all provide power to a single utility.  Since the weather varies in different places, this has the benefit of making the system as a whole a lot less variable.  Denmark sells power to Germany, Norway, and Sweden when their wind farms produce more power than they can use. 
  2. Moving to a national electricity system from the current system of regional grids would also ease the flow of wind power from one region to another.
  3. Time of Use/ time-based pricing.  Time of use pricing allows a utility to charge less or more for power depending on how much power is available at any given time.  Time of use pricing is currently a hodge-podge consisting of none at all for some utilities, and others that offer it (or even mandate it) for/to all customer classes.  Often time of use pricing simply consists of two prices: on- and off-peak, but the ideal goal for this is to actually have real time pricing, which will even depend on that day’s weather forecast (on windy days, electricity should be cheaper than otherwise.)  The ideal goal would be to eventually move all electricity customers to real-time or near real-time electricity pricing, so that customers who are willing to adjust their usage patterns are compensated for the service that they are providing to the system as a whole.
  4. Demand side management goes hand in hand with time of use pricing.  Demand side management involves giving customers incentives to keep their load from peaking too much at any one time.
  5. Dispatchable/Interruptible loads involve allowing the utility a certain amount of control over their customer’s energy use.  The classic example is installing a remote switch on an air conditioner, so that on a hot day, the utility can regulate it so that they don’t all come on a the same time, but rather take turns, lowering the peak demand on the grid.   Utilities typically pay their customers for this right for remote control.
  6. Large scale electricity storage: Pumped hydroelectric, flow batteries, hydrogen and stationary fuel cells, and compressed air energy storage are all ways to store large amounts of power when it is plentiful and cheap (on windy nights, for instance) until it is scarce and expensive (late afternoon and early evening.)
  7. Distributed energy storage, such as plug in hybrid or electric vehicles with vehicle to grid.  Vehicles which charge from the grid can be beneficial even if they are not capale of sending power back to the grid, simply because their owners can charge them only at non-peak times, a practice which is easy to incentivize with time of use pricing.
  8. New forms of generation that can serve as backup power.  Concentrating Solar with thermal storage, landfill gas turbines, and biomass gasification are all possibilities.  One often overlooked advantage of IGCC(“Clean Coal”) is that electric power from IGCC is generated by a gas turbine which burns the syngas product of the gasification step.  While it is quite possible that carbon capture and sequestration may never be made to work with IGCC, this is one reason (along with lower emissions of traditional pollutants and higher efficiency, which reduces carbon emissions for MWh generated) that renewable energy activists should prefer IGCC to old style pulverized coal plants.
  9. Increase energy efficiency, especially in appliances that are often used during peak times.  In most of the United States, peak load usually occurs on hot afternoons and evenings when air conditioners are running, so replacing an air conditioner with a more efficient one not only reduces overall energy use, it also reduced peak demand.  Once again, the institution of time of use pricing would give customers the incentive to upgrade the right appliances for energy efficiency first.   Here are two advances in efficient air conditioning I’m particularly excited about the Delphi HMX (formerly known as Coolerado), and thermally driven dessicant cooling.

For another well thought out perspective on energy storage, hop on over the the Ergosphere for the Engineer-Poet’s thoughts.

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Conversation with a wind skeptic

I’ve been having a long conversation with a wind skeptic who responded to my Gust Ceiling entry.    While the rest of us are thinking about ways to overcome the intermittentcy problem with wind, this Rucio is dismissing it out of hand because of that problem. 

 See the comments for our conversation.  We RE enthusiasts need people like this Rucio/Eric Rosenbloom to make sure that we’re not the ones in la-la land.  To paraphrase Paul Newman, if you look around and can’t tell who the lunatic fringe is, you’re it.

I’d like to point out that I jumped to a couple of conclusions myself, which he points out… I left these comments in, even though they do not make me look great.  They are there because I want people who are trying to make up their mind to know that I have not just invented myself a straw man in order to look good.

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The Gust Ceiling: How much wind is too much?

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

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

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

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

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

Other strategies not considered:

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

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

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

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