Clean Power

Published on July 18th, 2012 | by Adam Johnston

26

Wind Energy More Energy Efficient than Fossil Fuels

July 18th, 2012 by  

 
Here’s something that may surprise you. Wind energy is more efficient than carbon-based fuels. That’s despite all the best efforts of the dirty fuels industry to trick us into thinking that wind energy can’t match the efficiency of fossil fuels in producing electricity.

Photo Credit: wind turbine in Whitemoor, Cambridgeshire, UK via Shutterstock

A recent article I read on the matter pointed to some very interesting information. The article’s talking points came from UK government data. The article pointed out that renewable energy supplies 4%, or 14 Terra-Watt hours (TWh), of the nation’s electricity. What is even more interesting to note was that, despite renewable energy only providing a small fraction of Great Britain’s electricity, not even 1% of its energy is lost. In other words, wind and (and other renewable energies) are VERY, VERY efficient.

Now, contrast that to fossil fuels used to supply the electricity. Gas supplies about 48% of the country’s electricity needs, with 372 TWh. However, gas also loses 54% of its energy as heat.

The article notes it’s a very similar picture for coal and oil. Coal supports 28% of the UK’s electricity supply (297 TWh), while losing 66% of its energy as heat. Oil only supplies 3%, but it loses even a bigger chunk, 77%. Nuclear power supplied 16% of the U.K.’s electricity, while it lost 65% of its energy as heat.

Zoe Casey, from the European Wind Energy Association, and author of the article, made some interesting points as to why the fossil fuel industry has it wrong with regards to wind energy and efficiency:

“Wind energy opponents centre their arguments on the ‘capacity factor’ of a wind farm. The capacity factor of any power plant is a measure of the amount of energy it actually generates compared to its theoretical maximum output in a given time. No power plant operates at 100% of its capacity.

Wind farms do not operate at wind speeds of less than 4 metres per second, and they are shut down to prevent damage during gale force winds of 25 metres/second or more, or for maintenance. But conventional power stations also do not operate all the time – they stop generating electricity during maintenance or breakdowns.

Comparing the outputs of both sources does show that conventional power stations produce power at a level compared to their theoretical maximum that is currently higher than the level for wind energy. Wind power’s capacity factor is around 30% onshore and 40% offshore, increasing year on year as more wind turbines come online and technology improves. Meanwhile, data from the German Association of Energy and Water Industries (Bundesverband der Energie und Wasserwirtschaft) shows that fossil fuels are often below 50%, even in winter.”

Furthermore, as noted above, converting wind to electricity doesn’t result in the staggering losses of energy as heat.

Wind energy’s cost are coming down, while the United Kingdom and other places get a big bang for its buck with wind energy. Let’s hope that trend continues.

Source: Renewable Energy World





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About the Author

is expected to complete the Professional Development Certificate in Renewable Energy from the University of Toronto by December 2017. Adam recently completed his Social Media Certificate from Algonquin College Continuing & Online Learning. Adam also graduated from the University of Winnipeg with a three-year B.A. combined major in Economics and Rhetoric, Writing & Communications in 2011. Adam owns a part-time tax preparation business. He also recently started up Salay Consulting and Social Media services, a part-time business which provides cleantech writing, analysis, and social media services. His eventual goal is to be a cleantech policy analyst. You can follow him on Twitter @adamjohnstonwpg or check out his business www.salayconsultiing.com.



  • Suckit wind power

    I don’t know where this guy gets his numbers on the efficiency of coal and gas burners. Gas burners now with the main turbine (powered from gas) and a secondary turbine (powered from steam) are 80%-90% efficient. And the only thing that brings that number down is fast start ups needed to replace wind power when the wind dies out.

    • Bob_Wallace

      Where do you get your numbers?

      Here’s what I find on line…

      “In general in service Combined Cycle efficiencies are over 50 percent on a lower
      heating value and Gross Output basis. Most combined cycle units, especially the larger units, have peak, steady state efficiencies of 55 to 59%. Research aimed at 1370°C (2500°F) turbine inlet temperature has led to even more efficient combined cycles and 60 percent efficiency has been reached in the combined cycle unit of Baglan Bay , a GE H-technology gas turbine with a NEM 3 pressure reheat boiler, utilising steam from the HRSG to cool the turbine blades. Siemens AG announced
      in May 2011 to have achieved a 60.75% net efficiency with a 578 megawatts SGT5-8000H gas turbine at the Irsching Power Station
      .”

      http://en.wikipedia.org/wiki/Combined_cycle#Efficiency_of_CCGT_plants

      Peak, steady state efficiencies of 55 to 59%. Start up inefficiencies are not included in that 55 to 59% number.

  • echosyst

    If that headline were true then wind would be in use everywhere already without the need for subsidies. A “good” wind farm is not producing energy 70% of the time, as such it cannot meet any of the grid demand criteria. Forget it.

    • Bob_Wallace

      Here’s a hint.  30% capacity does not mean that the wind blows only 30% of the time.

      Here’s another hint.  Latest tech wind turbines are producing 50% of nameplate capacity.  30% is old tech.

      Here’s yet another hint.  Read more and hold off on the posting until you’re up to speed.

  • Ross

    I’d just highlight that wind is free and fossil fuels aren’t. 

    http://en.wikipedia.org/wiki/Energy_conversion_efficiency

    • Ergonef

      Actually, fossil fuels are just as free. You just have to pay for the use of the land and the equipment to procure them and use them. Which is the same with wind.

      • Ross

        Ok you win, substitute abundant and for all practical purposes inexhaustible for free. 

        • Bob_Wallace

          Don’t forget to add in extraction and processing costs.

          Oh, and the external costs of burning fossil fuels.

          Aside from all those many costs fossil fuels are just as free as sunshine and wind.

          Jeeeezzzzzzzzzzzzzeeeeeeeeeeeeeeee………

          • Ross

            LOL. Bob makes a good point. I conceded too easily as fossil fuels aren’t free in the sense I used it for wind as they impose lots of negative external costs on society that aren’t properly accounted for.

  • Ergonef

    This article manages to muddle the issue even more.

    ‘Efficiency’ is a matter of physics: how much of the energy in the source is converted into electrical energy. Coal plants are about 30% efficient, and natural gas plants can be near 60%, which is also where wind turbines are (not 99%, as this article implies).

    ‘Capacity factor’ is how much energy a plant produces in proportion to its maximum power rating. With conventional plants, that is generally a reflection of the time the plant is operating. Plants that are not base load providers (nuclear and large coal) are operated as needed to provide energy as demand fluctuates through the day. In contrast, wind turbine production fluctuates according to the wind, the output varying with the speed of the wind. Thus, although wind turbines are 60% or more efficient, and are available 95% or more of the time, their average production is only 20-40% of their power rating.

    Furthermore, wind turbines generate at or above their average capacity only 40% of the time.

    ‘Efficiency’ in the common understanding, however, is about reliability, ie, when electricity is needed, can the generator provide it? This is reflected in a plant’s ‘capacity value’, which is near 100% for conventional plants. But since wind turbines respond only to the wind, not the actual needs of the grid, it is generally
    given a capacity value of only 5-10%.

    • Bob_Wallace

      Right down to that last sentence, right down to that very last sentence, you were doing well.

      If the grid is designed to accept intermittent supply inputs such as wind, solar, tidal, etc. then “responding only to the wind” is irrelevant.

      If there is dispatchable supply, movable load, or storage available then all the power produced by an intermittent source can be utilized. 

      (BTW, best wind capacity is now over 50%.  24% to 50.6% – http://en.openei.org/apps/TCDB/ )

    •   @Bob_Wallace:disqus  Just what I wanted to reply.

      Storage will develop like crazy in the coming years and that will seal the fate of fossil based generation.

      When storage gets cheap enough (soon), then fossil plants loose all of their advantages. Their fuel bill and other factors (like nuclear safety) will make them inherently infeasible.

      • Bob_Wallace

        I partially agree.  But let’s look at a future in which natural gas stays cheap and no price is put on carbon.  (That is a distinct possibility in the US.)

        Natural gas LCOE is about $0.05/kWh, median.  That’s the price that must be bettered in order to force fossil fuel to go away.

        Wind is about $0.05/kWh, median.  Storage would have to have a negative cost in that environment.

        It’s looking like NG will push coal off the US grid fairly fast.  Partly due to lower fuel costs, part due to EPA pressure on coal plants to reduce emissions of mercury, etc.  It’s fairly unlikely new coal plants will be built because the capex and time to build are much better for NG.

        I think stored wind might eat into NG some.  If cheaper off-peak wind power can be stored at a very attractive cost then turbines will be idled some.  But I’m not sure that we’ll see a huge amount of “curtailable” wind.  NG also eats into the profitability of peak hour prices.  That reduces the rate of wind installation.

        Here’s what I see as our best hope.  Storage falls to very cheap.  Two cents per or less.  Solar falls to a nickle.  That would make stored renewable about six cents.

        At that point people would probably accept a small carbon price which would drive NG to seven cents.  Then NG goes into a very minor role of deep backup.

        The other future – the general public grasps the problem we’re facing and demands action.  A carbon price is set.

        Well, the third.  We bake.

        OK, a fourth and then I’m done.  It turns out that climate scientists were wrong and it was really an invisible fire-breathing dragon who was just messing with us.  Fun over, she stops messing with the world’s temps and hires out for marshmallow roasts. 

        •  🙂

        • David

          Bob – an important point – My utility charges me 12cents Kwh.  If solar can be brought down to 10 cents, with reverse metering – then I am ahead of the game to put panels on my roof.  Some utilities are charging significantly more (especially those using teired rate plans).  So – in your scenarios – do you see the possibility of rapid uptake of distrubuted solar? 

          • Bob_Wallace

            Yes.  

            My comments above were aimed at the wholesale side of the meter.Let me suggest that if you can install solar at 12 cents per kWh then you should.  If you put solar on your roof for the “same monthly” as what you pay the utility company now you will have locked in  your rate at 12 cents from day one until the system is paid for.Others utility bills will be getting more expensive while yours will stay the same.Over a 20 year period with 3% inflation the cost of “12 cents now” will average 15.7 cents.  It’s 15.7 cents you are working against, not 12.Then once your system is paid off you will pay zero per kWh for several more years, perhaps a few decades.At 10 cents per watt, rush to install.–Now, rapid uptake.  Germany, first quarter 2011, was installing solar at $2.44/watt.  No subsidies included in that price.If you lived in a 4.5 solar hour part of the US (some of the poorest for sun) and borrowed the money at 6% for 20 years to install $2.44/W solar the electricity would cost you $0.129/kWh.  Panels are cheaper second quarter this year than first quarter last year.  When we get as efficient as Germany then it will make sense for anyone paying a dime or more to install panels.If the wholesale minimum for electricity is five cents (the price of both wind and natural gas) the utility probably can’t deliver to retail customers for less than a dime.  I can see much more rapid uptake.Here’s another thing.  I suspect there is a psychological barrier that will fall when one can install a complete system for less than $10,000.  A 3kW system at $2.44/watt is $7,320.  Getting below $10k is going to make purchasing a lot less daunting to many.  

          • Ton of excellent points here.

            I’m also curious about social tipping points. There are always leaders, first followers, and then the tipping point. Germany has ~10% of homes on solar now, I think. Wondering if they are approaching a big tipping point. Imagine someone with 30 friends, 3 of them have already gone solar. How long until they and the others jump on board?

        • Some more possibilities:

          1) home solar has to compete with retail electricity. not LCOE. so, a bit more of a drop in home solar could put a lot more solar on roofs, bringing its cost down further as well as that of home energy storage as it ramps up, like it’s starting to in Germany & Japan.

          2) Nat gas prices rise… naturally. I might be wrong, but it seems to be artificially low. And there’s a lot of projection it will rise in price. But one never knows…

          • Bob_Wallace

            1) True.  But there’s another little twist in the the rope.

            Put a lot of owner solar on roofs and peak hour prices drop.  That can hurt wind and NG in the long run.  It might also cause overall retail prices to drop.  (All longer term speculation.)

            2) I haven’t been able to nail that one down.  One guy, a long time oil driller, who has earned my trust says that prices won’t stay down.  He says that the wells are dropping in output faster than some are admitting/factoring into their numbers. 

            He also says that current prices are too low to pay for new drilling.  That’s consistent with numbers I’ve seen on where the drilling rigs are right now.  They’ve been moved to the oil fields.

            Others claim that there is enough byproduct from oil to keep the price down.

            Futures market thinks NG prices will be up 33% two years from now and about double by 2020.

            BTW, all the predictions I’ve seen as to the amount of NG we have are based on 2010 burn rates.  We’re quickly jacking up burn and export rates for NG.  Any non-adjusted estimates might need to be cut by 50%.  

          • Thanks. That’s basically what i’ve read on the wells and prices.

            The last bit on burn rates is an interesting bit i hadn’t thought of or run across. 😀

      • echosyst

        There is no storage technology on the horizon that can handle the amount of energy required to power thousands of homes and buildings. You are dreaming. The cost would be astronomical in any case and make wind even more of a loser.

        • Bob_Wallace

          Pump-up hydro, CAES, sodium-ion batteries, liquid metal batteries, lithium-ion batteries, hydrogen, ammonia, ‘hot rock’ storage, ….

          Yep.  Nothing on the horizon.  Wind is a loser. Yep.  You got it scoped out Ace.  Glad you filled us in.
           

        • @echosyst

          Storage doesn’t need to supply the whole grid alone, it only needs to handle variations.
          If you build an intelligent grid which is capable of connecting huge areas, the variation gets limited. These grids are already under development here in Europe where solar and wind has been developed in large capacities. If Desertec ever gets to get built, these grid capacities will triple.

          It doesn’t matter if storage is expensive since both wind and solar prices are plumeting. In a couple of years, both solar and wind gets WAY below the typical grid prices so it can afford spending on storage.

          Moreover, it doesn’t matter if storage is expensive if a community decides that it wants to stop global warming and environmental pollution. Expensive is a relative term anyway.

          How much does a human life cost which is lost to enviromental pollution?
          How much would you pay to avoid your child getting asthma due to polluting power plants?

          How much does a destroyed planet (by GW) cost?

          How much would humanity pay if we knew that Earth becomes certainly unlivable due to GW?

          Believe me, expensive may be VERY-VERY cheap when you compare it to the real costs and not the costs which have 2/3 externalized and hidden from you.

          You may say that solar PV systems for homes are expensive. Yet, if I calculate the levelized cost of electricity with realistic input, it comes way below current end-user prices here in Hungary. Given the trend, it will be a no-brainer in a couple of years.

          • I keep forgetting you’re in Hungary. Man, you’ve got some GW deniers there, don’t you?

            It might be the norm here in Poland. Is very sad.

          • We have our fair share of them, no question about it.

            However, we have some positive influence from neighbours as well. Austria is extremely ahead of utilizing solar thermal (a lot of houses with solar collectors) and recently we had a big Iberdola wind farm built in the western part of the country. We also have some positive effects of the German solar boom. We don’t have anything similar in regards of installers and ease of projects but at least we can source panels cost effectively from the German market.

          • Nice to hear. 😀

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