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Wind Power

Discussion in 'Earth and Environmental Science' started by amusicsite, 2 Dec 2011.

  1. amusicsite

    amusicsite dn ʎɐʍ sᴉɥ┴ Staff Member

    Location:
    UK
  2. Shaun

    Shaun Über Geek

    Some interesting background material on renewables - and what seems to be a balanced reporting of the costs vs. benefits to wind power generation (and masses of pro/anti comments from readers too ... :wink:).

    Personally I think it is a massive (if not impossible) task to generate all of our electricity from renewable energy sources, and one which is compounded by the fact that we can't store electricity in any useable volumes - to be meted out as it is needed.

    The idea of a massive "super" grid is interesting though - if such energy could be constantly harvested and moved to any area it is needed - in the whole of Europe for example, then it might make it easier to capitalise on wider weather patterns.
     
  3. amusicsite

    amusicsite dn ʎɐʍ sᴉɥ┴ Staff Member

    Location:
    UK
    I think it has to interconnected networks, which we already have to a point there is an attempt at a Europe wide 'Super Grid'

    http://www.guardian.co.uk/environment/2011/apr/11/uk-netherlands-power-cable-britned

    [​IMG]

    If it's going to be 100% green energy (excluding nuclear) the I am a firm believer that the oceans are the key, they are the only natural source of energy that have a constant source, the moon (and other bodies) gravitational force on the oceans.

    If we could tap a fraction of 1% of the potential energy of the oceans then we would not need one wind turbine. Especially round Europe with great access to the coast from Portugal all the way up to Finland, all round Sweden and Norway, The islands (like us) and the Mediterranean coast.

    Especially if you have this network of under ocean cables, how easy it would be to dot a few tidal power generators along these routes plugged into the network.

    Wind and solar are good backups and may help produce supply nearer demand with the oceans providing the core backup power.

    There has still been very little research money and real world experiments in harvesting the oceans force. In places with serveer costal erosion it could even work as a sea break too.

    http://engineeringcases.knovelblogs...sting-from-ambient-vibration-and-ocean-waves/

    Would be interesting to see how much that 750MW costs and how much surface area it takes up. Then you could estimate how much sea area and cost it would be to get a sizeable portion of the energy from the oceans. Obviously there is the questions of how much it would cost to maintain, hod durable it was and how long it last for. But providing these are reasonable then it could mean much cheaper electricity after an initial big outlay.

    It all seems quite a simple robust system.

    http://www.pelamiswave.com/wave-energy/the-resource

    One of the sited generators makers claim

    So that would be up to a quarter of our demands with curent technology, and you can bet the technology would get better even if they tried to generate 10% of that target. So with a 100% increase in generation you would be approaching 50% of our needs via the ocean around us. I would guess that Ireland could do almost better and generate over 100% of their needs, then there is that huge pond behind Ireland...
     
  4. amusicsite

    amusicsite dn ʎɐʍ sᴉɥ┴ Staff Member

    Location:
    UK
    http://www.guardian.co.uk/environme...atteries-energy-storage-production-renewables

    The comments are quite interesting here.

    I've always liked the idea of http://www.fhc.co.uk/dinorwig.htm

    Basically dig out a huge space or two in a hill, we are already quite good at this. Could use an exhausted mine or some old man made cave. Ideally split onto two levels internally, or you can use a ground level water store.

    Then all you do is pump water from the lower store to the upper store when you have surplus power, then use gravity to dump it back down via turbines to generate top up power (full power in under 16 sec!) when needed. Seems the perfect thing to store both fresh water (although I guess you could also use sea water) and store potential energy.

    Would be interesting to see how much volume of water you would need to store a full days worth of demand.
     
    Shaun likes this.
  5. amusicsite

    amusicsite dn ʎɐʍ sᴉɥ┴ Staff Member

    Location:
    UK
    [​IMG]

    Wow, when they go, they really go! Can't take the Scottish weather...
     
  6. Shaun

    Shaun Über Geek

    http://www.reuters.com/article/2012/04/29/wind-farms-climate-idUSL6E8FR3H520120429
    By Nina Chestney

    LONDON, April 29 (Reuters) - Large wind farms might have a warming effect on the local climate, research in the United States showed on Sunday, casting a shadow over the long-term sustainability of wind power.

    Carbon dioxide and other greenhouse gases from burning fossil fuels contribute to global warming, which could lead to the melting of glaciers, sea level rise, ocean acidification, crop failure and other devastating effects, scientists say.

    In a move to cut such emissions, many nations are moving towards cleaner energy sources such as wind power.

    The world's wind farms last year had the capacity to produce 238 gigawatt of electricity at any one time. That was a 21 percent rise on 2010 and capacity is expected to reach nearly 500 gigawatt by the end of 2016 as more, and bigger, farms spring up, according to the Global Wind Energy Council.

    Researchers at the State University of New York at Albany analysed the satellite data of areas around large wind farms in Texas, where four of the world's largest farms are located, over the period 2003 to 2011.

    The results, published in the journal Nature Climate Change, showed a warming trend of up to 0.72 degrees Celsius per decade in areas over the farms, compared with nearby regions without the farms.

    "We attribute this warming primarily to wind farms," the study said. The temperature change could be due to the effects of the energy expelled by farms and the movement and turbulence generated by turbine rotors, it said.

    "These changes, if spatially large enough, may have noticeable impacts on local to regional weather and climate," the authors said.

    MORE RESEARCH NEEDED
    But the researchers said more studies were needed, at different locations and for longer periods, before any firm conclusions could be drawn.

    Scientists say the world's average temperature has warmed by about 0.8 degrees Celsius since 1900, and nearly 0.2 degrees per decade since 1979. Efforts to cut carbon dioxide and other greenhouse gas emissions are not seen as sufficient to stop the planet heating up beyond 2 degrees C this century, a threshold scientists say risks an unstable climate in which weather extremes are common.

    The Texas study found the temperature around wind farms rose more at night, compared with nearby regions. This was possibly because while the earth usually cools after the sun sets, bringing the air temperature down, the turbulence produced by the farms kept the ground in their area warm.

    Previous research in 2010 by other U.S. scientists found wind farms could make the nights warmer and days cooler in their immediate vicinity, but those effects could be minimised by changing turbines' rotor design or by building the farms in areas with high natural turbulence.

    That research was based on evidence from two meteorological towers over a six-week period.
    Although the warming effect shown in that study and the latest research is local, and small compared to overall land surface temperature change, the findings could lead to more in-depth studies.

    The authors of the study released on Sunday said: "Given the present installed (wind farm) capacity and the projected installation across the world, this study draws attention to an important issue that requires further investigation."

    "We need to better understand the system with observations and better describe and model the complex processes involved to predict how wind farms may affect future weather and climate."

    Commenting on the study, Steven Sherwood, co-director of the Climate Change Research Centre at the University of New South Wales in Australia, said: "Daytime temperatures do not appear to be affected. This makes sense, since at night the ground becomes much cooler than the air just a few hundred metres above the surface. The wind farms generate gentle turbulence near the ground that causes these to mix together, thus the ground doesn't get quite as cool." (Edited by Pravin Char)
     
  7. Shaun

    Shaun Über Geek

    'casting a shadow over the long-term sustainability of wind power' - really?

    Surely the reduced production of fuels and the subsequent reduction in emissions (globally) - negates any such localised warming around the farms themselves?
     
  8. amusicsite

    amusicsite dn ʎɐʍ sᴉɥ┴ Staff Member

    Location:
    UK
  9. amusicsite

    amusicsite dn ʎɐʍ sᴉɥ┴ Staff Member

    Location:
    UK
    These can raise the temperature a couple of degrees C.

    "Despite concerns raised about its possible contribution to global warming, comparisons between urban and rural areas show that the urban heat island effects have little influence on global mean temperature trends."

    Probably the same 'experts' think this is fine...
     
  10. amusicsite

    amusicsite dn ʎɐʍ sᴉɥ┴ Staff Member

    Location:
    UK
    [​IMG]
     
    Shaun likes this.
  11. Shaun

    Shaun Über Geek

    Less dramatic reporting of the same research: http://www.newscientist.com/article/dn21759-wind-turbines-can-cause-localised-warming.html

    'The satellites give temperature measurements with a spatial resolution of roughly 1 square kilometre' - so quite a large "mean" temperature area then?

    "Despite the warming effect identified by his team, Zhou points out that the region overall has not got significantly warmer since 2003. This suggests that the wind farms are not having a big effect on regional climate." - oh, right, so - erm - not really a problem at all then? Globally speaking!!! :wink:
     
  12. amusicsite

    amusicsite dn ʎɐʍ sᴉɥ┴ Staff Member

    Location:
    UK
    If you have read the Bad Science book (http://www.badscience.net/) you would recognise this as a 'paid for new report'. This is typically when a company, let's say for example an oil company, creates or twists a report to their own needs. So they take something like this and pay a science reporter to spin it so you get a report that is something like wind farms cause global warming. Often with the get out of jail free card of 'more research is needed' to make it sound like they are not miss-reporting the story.

    Lazy editors may well ignore their science team (if they even have one) and just go ahead and reprint the story. Maybe getting someone who know nothing about it to change the odd word to match their style. Then the company that paid for them get a few more people who will forever say things like "but wind farms cause global warming" or "electric cars cause as much pollution". They forget the details, of which there are not much to start with, and remember the sound bites like Wind Farm make it warmer or Generating electricity is polluting. While failing to see the bigger picture like most things we build change the local environment or it's easier to make non-polluting electricity than it is to make non polluting petrol.

    Also if you can get one of the respected papers to pick it up then you can wave it under the noses of government officials to prove these alternatives to your business are rubbish.

    Unfortunately there seems more bad science than good science these day. Thank god for New Scientist!

    New Scientist.


    Reuters

    See the difference is the summing up. New Scientist say the over all region's temperature is not affected but more research is needed to help understand any effect it's having and reduce it. Where as the Reuters article references another (unnamed) report that studied 6 weeks of data, rather than the 8 years in the new study, that claim that it could make warmer nights and cooler days and wrap it off saying that report is probably wrong about the days. But manage to get in the line about " predict how wind farms may affect future weather and climate" even though neither report seems to indicate that either weather or climate are likely to be affected.
     
  13. amusicsite

    amusicsite dn ʎɐʍ sᴉɥ┴ Staff Member

    Location:
    UK
    Not easy to find, but here's that actual Q&A report from the people who made the report.

    http://www.atmos.albany.edu/facstaff/zhou/tmp/press_release_QA.pdf
    And here's the report
    http://www.atmos.albany.edu/facstaff/zhou/tmp/nclimate1505-aop.pdf

    Here's some of the bits missing from both reports.

    Why do the operating wind turbines warm nighttime temperature?
    This warming effect is most likely caused by the turbulence in turbine wakes acting like fans to pull down warmer near surface air from higher altitudes at night. Typically nighttime has a stable atmosphere with a warm layer overlying a cool layer. Enhanced vertical mixing mixes warm air down and cold air up, leading to a warming near the surface at night. Daytime often has an unstable atmosphere with cool air lying over warmer air. Turbulent wakes mix cool air down and warm air up, producing a cooling near the surface during the day. However, daytime mixing is already very large due to solar heating. Hence, the turbine-enhanced turbulent mixing may play a smaller role during the daytime.

    we express the warming effect as a linear trend in °C per decade units. This is just one simple way to quantify the wind farm impacts while reducing the year-to-year data noise. The estimated warming trend only applies to the study region and to the study period, and thus should not be extrapolated linearly into other regions (e.g., globally) or over longer periods (e.g., for another 20 years). For a given wind farm, the warming effect would likely reach a limit rather than continue to increase if no new wind turbines are added.

    satellite data do contain errors and noise due to cloud contamination and imperfection of retrieval algorithms. Uncertainties also exist in locating wind turbines as well as their operating times. In addition, other factors may also modify local land surface temperature.

    compared to impacts of other human-made land use changes, the estimated warming over the wind farms is small. The “urban heat-island” effect, for example, in Austin TX or phoenix in AZ, could be several degrees °C warmer than the surrounding less developed areas.

    Overall, the warming effect reported in this study is local and is small compared to the strong background year-to-year land surface temperature changes. Very likely, the wind turbines do not create a net warming of the air and instead only re-distribute the air’s heat near the surface (the turbine itself does not generate any heat), which is fundamentally different from the large-scale warming effect caused by increasing atmospheric concentrations of greenhouse gases.

    While converting wind’s kinetic energy into electricity, wind turbines modify surface-atmosphere exchanges and transfer of energy, momentum, mass and moisture within the atmosphere. These changes, if spatially large enough, might have noticeable impacts on local to regional weather and climate.

    So firstly it's temperatures gathered from satellites with plenty of noise in the data due to clouds and the like. Also they don't seem exactly sure where these wind farms are and have not factored in if they are operating or not. Also the effect should stabilise when you stop adding new turbines and it's possibly not even heating up the air, might just be redistributing the temperature more evenly over the lower near surface areas.

    I did stumble on a quote saying this turbulence of the air could be good for crops as it may increase the airflow over them. So maybe all we need to do is grow cabbages under the wind farms and it might be all right.

    On a science note, could you have wind turbines that work in opposite directions to help negate these effects? Say a row of turbines with alternate clockwise, anticlockwise arrangement. Or a row of clockwise followed by a row of anticlockwise?

    I do remember reading a while ago that vertical wind turbine could be packed closer together than traditional propeller designs because the created less or different turbulence which did not affect other turbines nearby, where are the propeller versions have a huge drop off with performance if they are located near another one.

    [​IMG]
     
    Shaun likes this.
  14. Shaun

    Shaun Über Geek

    Excellent post - and puts the research in a whole different light than Reuters reported it, especially:

    "The estimated warming trend only applies to the study region and to the study period, and thus should not be extrapolated linearly into other regions (e.g., globally) or over longer periods (e.g., for another 20 years). For a given wind farm, the warming effect would likely reach a limit rather than continue to increase if no new wind turbines are added.

    satellite data do contain errors and noise due to cloud contamination and imperfection of retrieval algorithms. Uncertainties also exist in locating wind turbines as well as their operating times. In addition, other factors may also modify local land surface temperature."
     
    amusicsite likes this.
  15. classic33

    classic33 Über Geek

    Blue Peter did something like that in the Welsh countryside when John Noakes was on it.

    Where did your picture of the turbine fire come from?
     
  16. amusicsite

    amusicsite dn ʎɐʍ sᴉɥ┴ Staff Member

    Location:
    UK
  17. amusicsite

    amusicsite dn ʎɐʍ sᴉɥ┴ Staff Member

    Location:
    UK
  18. An interesting idea, but an annoying website ... Fullscreen popover ads are bad enough, but then autoplaying videos as well - aaargh! :thumbsdown:
     
  19. SatNavSaysStraightOn

    SatNavSaysStraightOn Well-Known Geek

    I didn't get any of that. No popover ads or autoplaying videos, just the New Scientist website.
     
  20. amusicsite

    amusicsite dn ʎɐʍ sᴉɥ┴ Staff Member

    Location:
    UK