Realities of the Modern-Day Grid Cancel Some of Wind Power’s Carbon Savings

May 31st, 2012 by Joshua S Hill

Update: following the publishing of this piece, we got the following important note from AWEA, which I am reposting in full here before the original article:

A recent analysis from Argonne Laboratory has generated some press interest for its conclusion that adding current levels of wind energy to the grid yields even greater reductions in emissions of harmful pollutants than expected, but that at levels of wind energy several times higher than are on the grid today, the incremental pollution savings of adding wind energy to the grid are somewhat smaller than they are at lower levels of wind. Unfortunately, this study’s findings have been misreported in the press, so we’d like to set the record straight:

- Much of the press coverage of this study is incorrectly reporting that the study finds that wind energy does not reduce pollution, or that the pollution savings are always smaller than expected. The study is explicitly clear that neither of those interpretations is correct.

- “The study finds that at the wind energy levels of today and the foreseeable future, wind energy’s emissions savings are even larger than expected (12% carbon dioxide emissions savings with 10% of the electricity on the grid coming from wind, 21% carbon dioxide emissions savings at 20% wind).”

- The study acknowledges that its findings are a theoretical exercise based on the assumption that power plants in Illinois are operated in isolation from those in other states, and as a result the study’s conclusions have little to no bearing on how the actual utility system works, particularly at high levels of wind generation.

- The study also acknowledges that it uses very outdated and unreliable estimates for making assumptions about the efficiency of fossil-fired power plants at different output levels.

- Other analyses using more accurate assumptions and more reliable sources have found that wind’s emissions savings are as large or larger than expected.

- Real-world data confirms that states that have added significant amounts of wind energy, such as Illinois, have seen fossil fuel use and emissions decline by as much or more than expected.

- Finally, analysis of readily available DOE data puts to rest the idea that wind energy has a significant negative impact on the efficiency of fossil-fired power plants.
Wind energy is one of the most environmentally friendly ways to generate electricity. Wind energy emits no pollution, creates no hazardous waste, and uses virtually no water. All of these advantages are beneficial to wildlife, and they are not shared by any non-renewable energy source.

For a more detailed analysis of the Argonne study, please see here: http://www.awea.org/blog/index…

Tom@AWEA

The realities of the modern day power grid are the problem behind the inefficiencies created when more wind power is connected, says a new report released by researchers at the U.S. Department of Energy’s (DOE) Argonne National Laboratory.

Argonne scientists modeled the Illinois electric grid in an effort to determine how wind energy affects carbon dioxide emissions by testing how more wind power added to the grid would affect the system. They found that having to adjust for the inclusion of wind power adds inefficiencies that cancel out some of the carbon dioxide reduction.

The problem?

The older technology running in the background is what hampers wind’s carbon-dioxide-reducing properties. Because wind doesn’t blow all the time, the grid operators sometimes have to turn on extra fossil-burning plants to keep up with the demand.

“Turning these large plants on and off is inefficient,” explained study author Lauren Valentino. “A certain percentage of the energy goes into just heating up the boilers again.”

“Illinois gets its strongest winds at night, when demand is low,” said co-author Audun Botterud, an Argonne energy systems engineer. “At the same time, we have a high fraction of very large, inflexible power plants in the system.”

Botterud notes that the best solution would be to find a way to store unused energy created when the wind is blowing and use it for peak times when the wind may have died down, but there is not yet a good and cheap way to store such energy.

Source: Argonne National Laboratory
Image Source: Tom/shock264

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Tags: electrical grid, Grid, Illinois, power grid

About the Author

Joshua S Hill I'm a Christian, a nerd, a geek, and I believe that we're pretty quickly directing planet-Earth into hell in a handbasket! I also write for Fantasy Book Review (.co.uk), and can be found writing articles for a variety of other sites. Check me out at about.me for more.

Wilbur

But even without renewables, the modern power grid is such that alot of plants have to shutdown overnight as the minimum demand is significantly different to the peak demand. And the gap is getting more with increases in domestic AirCon/heating during the day, and more energy efficient lights at night.
LaurenAWEA

A recent analysis from Argonne Laboratory has generated some press interest for its conclusion that adding current levels of wind energy to the grid yields even greater reductions in emissions of harmful pollutants than expected, but that at levels of wind energy several times higher than are on the grid today, the incremental pollution savings of adding wind energy to the grid are somewhat smaller than they are at lower levels of wind. Unfortunately, this study’s findings have been misreported in the press, so we’d like to set the record straight:

– Much of the press coverage of this study is incorrectly reporting that the study finds that wind energy does not reduce pollution, or that the pollution savings are always smaller than expected. The study is explicitly clear that neither of those interpretations is correct.

– “The study finds that at the wind energy levels of today and the foreseeable future, wind energy’s emissions savings are even larger than expected (12% carbon dioxide emissions savings with 10% of the electricity on the grid coming from wind, 21% carbon dioxide emissions savings at 20% wind).”

– The study acknowledges that its findings are a theoretical exercise based on the assumption that power plants in Illinois are operated in isolation from those in other states, and as a result the study’s conclusions have little to no bearing on how the actual utility system works, particularly at high levels of wind generation.

– The study also acknowledges that it uses very outdated and unreliable estimates for making assumptions about the efficiency of fossil-fired power plants at different output levels.

– Other analyses using more accurate assumptions and more reliable sources have found that wind’s emissions savings are as large or larger than expected.

– Real-world data confirms that states that have added significant amounts of wind energy, such as Illinois, have seen fossil fuel use and emissions decline by as much or more than expected.

– Finally, analysis of readily available DOE data puts to rest the idea that wind energy has a significant negative impact on the efficiency of fossil-fired power plants.

Wind energy is one of the most environmentally friendly ways to generate electricity. Wind energy emits no pollution, creates no hazardous waste, and uses virtually no water. All of these advantages are beneficial to wildlife, and they are not shared by any non-renewable energy source.

For a more detailed analysis of the Argonne study, please see here: http://www.awea.org/blog/index.cfm?customel_dataPageID_1699=16631

Tom@AWEA
- http://cleantechnica.com/ Zachary Shahan
  
  Thank You, Lauren. I’ve upgraded this comment to an update preceding the original article.
Ross

Presumably the Rock Island line from Iowa is one example of the various measures that can help prevent having to fire up legacy power like dirty coal.

http://cleantechnica.com/2012/03/07/big-wind-renewable-energy-boost-as-illinois-gov-quinn-announces-rock-island-clean-line-project-labor-agreement/
JohnInMA

The problem goes beyond the real world carbon accounting. As primarily wind and solar are introduced into a network, the “backup” generating capacity must increase, too. If, for example, 50% of Illinois’ energy came from those two intermittent renewable sources, almost that same capacity is needed as backup for the worst case scenario of stagnant air, and overcast skies. So, on top of inefficiencies in cycling the generating plants, there are also real capital costs that can be excessive in some cases. At best for now, there could be parity, or balance, in the additional capacity costs and the energy storage costs.

In certain U.S. regions there are other characteristics that help reduce some of these problems. For example, California can mandate and increase its renewable portfolio because the Western Interconnection (WECC) allows for sufficient sharing across the transmission network that the immense amount of hydropower can be somewhat dispatched when needed – meaning when renewable sources are running significantly below capacity.
- http://ronaldbrak.blogspot.com.au/ Ronald Brak
  
  Here in Australia the capacity to meet peak demand already exists, so there is no need to increase back up generating capacity. It’s there already.
  - JohnInMA
    
    Surely your non-renewable facilities are decommissioned for age or other economic factors from time to time. Even in the case where demand is flat, at some point Australia will face the situation more than once where a significant investment is needed to either bring an existing facility up to modern operational standards or to replace it with another type that is equally dispatchable. It is my understanding that coal is still a primary energy source in the country. Even if the coal facilities are replaced by natural gas fired facilities, even on a kW equal basis, the carbon and economic issues still remain.
    
    That is the whole point here. The intermittent and somewhat unpredictable nature of wind and solar requires that they not be treated as pure base load generators, with sufficient dispatchable backup from non-renewable sources. They do not simply replace existing capacity. That changes the impact of the two sources on both emissions and costs.
    
    Other renewable sources such as hydropower and geothermal systems do not have exactly the same characteristic, but typically have non-favorable economics by comparison. As noted in this brief article, energy storage is a key remedy to the emissions problem but doesn’t yet solve the problems with costs.
    - http://ronaldbrak.blogspot.com.au/ Ronald Brak
      
      Here in Australia we have an electricity market that pays people for supplying electricity to meet demand. As a result, people try to supply electricity at the lowest cost they can in order to make the most money. If someone starts selling electricity from a solar panel they don’t have to compensate anyone for the times they don’t sell electricity from a solar panel. If someone sells electricity from a coal plant they dont’ have to compensate anyone for when they shut that plant down for maintenance. It may sound like a weird system, but technically it’s supposed to be about the most economic way to supply electricity.
    - Bob_Wallace
      
      I agree that it will take affordable storage in order to get fossil fuels off our grids. And because there is an inefficiency in starting and stopping fossil fuel plants there is a certain carbon cost that has to be added in.
      
      But that’s not a condemnation of renewable energy. It’s just a marker along the road away from fossil fuels.
      
      We are seeing a move away from older thinking “base load” concepts and toward “electricity when it’s needed” models. Neither wind nor solar can ever be 100% reliable baseline, there are times at which neither the wind blows nor the sun shines. But both are well on their way to being the cheapest ways to fill the grid, both in terms of cost and lack of environmental/health damage.
      
      Massive amounts of work are being done on storage. New battery technologies are looking very promising. New pump-up is being developed.
      
      New ways to do demand-shift are being discovered.
      
      With each new way to store supply or time-shift demand we will have to cycle dispatchable fossil sources less often. Those carbon-nasty startups and shutdowns will fade away.
      - JohnInMA
        
        Remarkably, it sounds like we agree on the technology progress and future needs but only have different perspectives on bridging the gaps. Keep in mind that there are other factors to address beyond simple power production levels, and they become more sensitive as the portion of renewable sources grows. I’m referring to power quality concerns, material costs, areal needs, etc. For example, there is every reason to believe that as battery production increases, material costs will rise accordingly. But we agree there is a path to high penetration of renewables. Eventually.
      - Bob_Wallace
        
        Read up on MIT’s liquid metal batteries.
        
        http://www.masshightech.com/stories/2012/02/13/daily35-MIT-advances-liquid-metal-battery-technology.html
        
        And watch the TED talk.
        
        http://www.ted.com/talks/donald_sadoway_the_missing_link_to_renewable_energy.html
        
        Now, it would be foolish to hold that this technology will absolutely work as predicted. But it’s only one approach. The Aquion info I posted is another.
        
        I see no problems of rising cost with large scale production due to material shortage. Neither of these technologies use hardtoobtainium.
        
        I don’t see areal problems. These batteries can be stacked high in lower value sites. They could go into the 2nd, 3rd, 4th, … basements of new construction. We could fill up brownfields with them. Old, no longer used factory buildings could be re-purposed.
        
        Think of how much real estate we now use for mining, slag heaps, coal plants, etc. Batteries can be widely distributed close to where the power is needed and can use marginal sites in those areas.
        
        Power quality concerns – batteries have almost instant response to grid needs. Adding large amounts of batteries to the grid will greatly simplify the job of managing the grid.
        
        I do expect we define “eventually” differently. I think we’re seeing the first few balls of snow that proceed the avalanche roll down the mountain.
        
        Look back at past technology shifts. Once a critical “good enough” threshold is passed the old generally gives away to the new very rapidly.
    - Bob_Wallace
      
      John, let me copy over some info about a promising grid storage battery.
      
      Aquion Energy – sodium ion (“salt water”) batteries.
      
      Inexpensive materials. Activated carbon anode and a sodium- and manganese-based cathode.
      
      Operate at room temperature. No self discharge or problems in high heat conditions.
      
      Can be 100% discharged without damage.
      
      High tolerance to battery mismatch.
      
      100% recyclable.
      
      Third party testing >5,000 cycles rapid charges with no degrading. Company expects 20,000 cycles when fully developed.
      
      Third-party tests have shown that Aquion’s battery can last for over 5,000 charge-discharge cycles and has an efficiency of over 85 percent.
      
      Tested for two calendar years so far with no loss of performance.
      
      Expected price around $300/kW.
      
      @5,000 cycles = $0.06/kWh, @10,000 cycles = $0.03/kWh, @20,000 cycles = $0.015/kWh.
      
      (Back of envelope calculations using 10k cycles)
      
      $0.05/kWh Wind + $0.03/kWh Storage + Overhead + 15% Loss (85% Efficient) =~ $0.10/kWh Stored Wind.
      
      Solar is expected to fall to close to $0.06/kWh.
      
      That makes a combination of wind, solar and stored wind/solar cheaper than new nuclear, new coal or peaker gas. (Or old coal if you add in externalities.)
      
      Lighter weight than lead acid batteries – cheaper shipping.
      
      Going into production. Currently setting up factory in Pennsylvania. Should be shipping evaluation units to utilities later this year. Expect to be manufacturing in 2013.
      
      http://www.aquionenergy.com/applications/
      
      If Aquion produces what they claim they can produce then many of the fossil cyclings that you
      point out will cease. There will be no need to build additional fossil fuel backup for new renewable generation.
      
      And the liquid metal batteries coming out of MIT look to be even more promising that Aquion’s sodium-ion batteries.
      - JohnInMA
        
        I’m very familiar with both of those technologies as well as Axion’s work. Again, we probably have different viewpoints on the timeline and viability at scale. Thanks!
- Bob_Wallace
  
  “As primarily wind and solar are introduced into a network, the “backup” generating capacity must increase, too.”
  
  And the result is? Wind and solar produce power a significant amount of time and during those periods fossil fuels are not burned.
  
  The other choices? Burn fossil fuels 100% of the time. Or install more storage and identify more dispatchable load.
  - JohnInMA
    
    You missed my point and the point of the article. There are some limitations that are real. Why hide them? In order for renewable energy to replace fossil-sourced energy significantly, or completely, they need to be addressed.
    
    I am very much a renewable energy advocate – a portion of my role involves them. But I’m always left scratching my head by those who are more ardent (greenies?) who react to any criticism by accusing a person of being against renewable energy, and perhaps other environmental aims.
    
    Storage solutions have not become cost effective, although a lot of progress has been made. For now it all comes down to how much additional cost ratepayers will live with as to how much renewable energy is fed to the network.
    - Bob_Wallace
      
      Of course there are problems yet to be solved. Does that mean that they are unsolvable? And who is hiding those problems? This site if full of posts on approaches to solving the many remaining problems to be solved.
      
      And exactly where did anyone accuse you of being against renewables? Is not accepting your opinion as the absolute truth a personal attack on you?