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Tech Allows Stable Integration of Wind In the Power Grid 235

Posted by timothy
from the giant-whooshing-sound dept.
diegocgteleline.es writes "One of the most frequently raised arguments against renewable power sources is that they can only supply a low percentage of the total power because their unpredictability can destabilize the grid. Spain seems to have disproved this assertion. In the last three days, the wind power generation records with respect to the total demand were beaten twice (in special conditions: a very windy weekend, at night): 45% on November 5 and almost 54% last night (Google translation; Spanish original). There was no instability. These milestones were accomplished with the help of a control center that processes meteorologic data from the whole country and predicts, with high certainty, the wind and solar power that will be generated, allowing a stable integration of all the renewable power. You can see a graphic of the record here."
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Tech Allows Stable Integration of Wind In the Power Grid

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  • by Rising Ape (1620461) on Sunday November 08, 2009 @03:48PM (#30024960)

    Wind generally changes slowly enough that it doesn't cause massive instability providing you have sufficient backup. However, there are other problems.

    Getting the percentage that high occasionally isn't amazing, especially during a time of low demand such as night. The hard part is generating an average of 50% wind overall (e.g. over a year).

    Say the baseload demand is 20 GW, then you can have 20 GW of wind power installed without worrying about what to do if too much is produced. So you could even get nearly 100% wind power occasionally. The problem is for the rest of the time when demand is higher or it isn't windy. The capacity factor of wind is about 30%, and baseload is typically about 50% of average load, so that means on average you're only generating 15% of your total electricity by wind power.

    • by zmooc (33175) <zmooc&zmooc,net> on Sunday November 08, 2009 @04:34PM (#30025328) Homepage

      Well. Just look at the graph linked in the article.

      https://demanda.ree.es/generacion_acumulada.html [demanda.ree.es]

      Note that the bottom drops below the zero line every now and then. Just before and after that the net hydroelectric power output drops to zero. I figure that's pumped-storage hydroectric plants filling their storage. Spain has at least 3 gigawatt worth of such plants. It doesn't solve the entire problem at this time, but it will sure help raise your baseline-example of 20GW quite a bit.

      http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity [wikipedia.org]

      • by grimJester (890090) on Sunday November 08, 2009 @05:26PM (#30025754)
        In addition, conventional hydroelectric dams can save up water and release it when necessary.

        I assume Spain simply builds up as much pumped-storage hydro as needed. They seem to have [wikipedia.org] around as much pumped-storage as they have (wind capacity * load factor).

        Anyway, I doubt many countries will face the problem of having too much wind power in the near future. Denmark currently has around 20% wind and sells off any excess to Norway, which in turn has huge amounts of hydro. Note that there is currently no other country that has more than the 15% figure quoted by GP. The US has room for building out 10 x the current capacity without worrying about storage.
    • Re: (Score:2, Informative)

      If combined with a massively redundant combination of solar (ie, almost every building has em), hydro and nuclear, we're talking business. Left over power can be spent on hydrolysis plants to produce hydrogen fuel, and we have almost zero emissions.
    • There was a paper published a couple years ago by dutch researchers that proposed to give discounts for refrigerated warehouses. They would lower their thermostats a couple degrees, but would be given a signal to stop their refrigeration units when the load gets too high. The couple degrees would be enough of a buffer to last a few hours. They calculated it would be enough to handle wind up to 30% of the total power generation.

      This kind of thing is already done, by the way, but on a limited scale. Large ind

      • Re: (Score:2, Insightful)

        by QuoteMstr (55051)

        Not this conservation crap again. Simple mathematics shows that conservation is not a "solution" to our energy crisis. It's not even close.

        Population increases exponentially, and power demands must therefore increase exponentially as well. If we add in quality-of-life improvements, power demand will increase even faster than population growth.

        Now, on the other hand, all conservation can do is shave a constant factor off our current per-capita energy costs. It won't do anything for the asymptotic increases.

        A

    • by dbIII (701233)

      Wind generally changes slowly enough that it doesn't cause massive instability

      I'll add a bit more. Since around the 1960s things that change no more rapidly that a large mining dragline scooping out another shovelful shouldn't cause instability. Also consider that entire large coal fired units drop out without warning at times but the lights stay on. Control systems can handle fairly large and sudden changes.

  • by imsabbel (611519) on Sunday November 08, 2009 @03:54PM (#30025014)

    Nothing is ever a complete solution, for anything.

    But every single Joule helps.

    • by maharb (1534501)

      I think that is well known. The issue is how many different renewable sources need to be put in place to achieve one joule of energy consistently with no possible variation. What you have is an issue of no meaningful relation between the different renewable sources creating situations where many many different sources of energy could all be producing zero, and other situations where many sources will be producing more than enough. Unfortunately this sort of solution doesn't work because humans demand con

      • by vlm (69642)

        Unfortunately this sort of solution doesn't work because humans demand consistent energy not just a total or average.

        Luckily, many industrial uses do not necessarily require constant energy, and can tolerate "total" or "average over certain intervals" power contracts.

        For "total" or "very long term average" power contracts, we have copper refineries, and electrorefining in general. "Lights out manufacturing" style numerically controlled machine tools can toggle their motors on and off more or less as power is available (but never interrupt the control computers power...). Desalinization plants simply fill water tanks wit

      • Its a FALSE argument to claim alternatives can not work because they can't provide constant power.
        There is a whole world of power storage solutions out there being completely ignored OR people are simply ignorant. It could be come an industry on some level or be a completely private industry where anybody with the tech could buy power and sell it back later for a profit.

        We can leave the market to handle load balancing. Look at flywheel power storage, flow batteries, hydro power storage, or even fuel cells.

  • 45% and 54% for Spain. If you can upgrade the scale, you can bring those 2 numbers very close together.

  • by flaming error (1041742) on Sunday November 08, 2009 @03:57PM (#30025040) Journal

    renewable power sources ... can only supply a low percentage of the total power because their unpredictability can destabilize the grid.

    As much as I'd like to see more renewable energy, this counter-example probably doesn't help. Spain has a somewhat modern and well maintained power grid. In this year's "Infrastructure Report Card", The American Society of Civil Engineers rated the USA's power grid "D+". (Unfortunately their website is down; here's google's cache [74.125.155.132]. Talk about failing infrastructure...)

    • by amorsen (7485) <benny+slashdot@amorsen.dk> on Sunday November 08, 2009 @04:34PM (#30025322)

      In the short term ( 1 minute), modern wind turbines have a stabilizing effect on the grid. There's quite a bit of inertial energy stored in the wings when the turbines are running which helps handling unexpected faults (e.g. a power line failure). Also, the electronics can supply as much reactive effect as the peak effect of the wind turbines even when the turbines are completely stopped.

      Anyway, in the medium term many countries will have to move towards HVDC lines to help the grid. A completely AC synchronized grid like what is common today is too vulnerable to faults spreading, because each power line can only switch on and off. With HVDC you can say "transport 500MW" and it will transport that amount, and if the consumer end tries to sink 1GW, the line will just keep providing 500MW. With AC the line will be forced to provide 1GW or shut down entirely. To make an AC grid work you need a strong central authority who can tell everyone how much to produce and when, and this is incompatible with both a free market for electricity and a large amount of power producers.

      • by jeffstar (134407)

        Also, the electronics can supply as much reactive effect as the peak effect of the wind turbines even when the turbines are completely stopped.

        can you expand on this? Is it a synchronous machine inside a wind turbine? They can be used as a synchronous condenser to supply reactive power when the turbine is stopped?

        What electronics can do this?

        • Re: (Score:2, Informative)

          by Anonymous Coward

          can you expand on this? Is it a synchronous machine inside a wind turbine? They can be used as a synchronous condenser to supply reactive power when the turbine is stopped?

          What electronics can do this?

          It's typically induction or permanent magnet generator inside the wind power plant. As far as I know synchronous machines are not used because wind cannot rotate the blades at a constant speed. The power is supplied to grid with frequency is converter. Frequency converter can supply the grid with reactive power during the disturbances.

          see:
          http://en.wikipedia.org/wiki/Low_voltage_ride_through

      • Re: (Score:3, Informative)

        by angel'o'sphere (80593)


        With HVDC you can say "transport 500MW" and it will transport that amount, and if the consumer end tries to sink 1GW, the line will just keep providing 500MW.

        That is wrong. If you attach more consumers to the line the line will break down (voltage and with voltage current will break down).


        To make an AC grid work you need a strong central authority who can tell everyone how much to produce and when, and this is incompatible with both a free market for electricity and a large amount of power producers.

        As soon

        • by amorsen (7485)

          That is wrong. If you attach more consumers to the line the line will break down (voltage and with voltage current will break down).

          With HVDC you have power electronics at each end. Those can limit the power drawn to whichever amount you want, to protect the producer end.

          The rest of your article is about all the management an AC grid needs -- which is why it works better when supplemented with HVDC lines.

  • by faragon (789704) on Sunday November 08, 2009 @04:09PM (#30025122) Homepage
    Disclaimer: I'm a Spanish citizen, living in Spain.

    First of all, I want to remark the great work of the REE company ("Red Eléctrica Española" stands for "Spanish Electric Power Network", the monopoly for electric power distribution), they not only do a great work routing and adapting the production to the user energy demand, but also provide a lot of useful information about power consumption, production/consumption balance, etc.

    The dark side of the problem is that although there is a huge amount of "green energy" being generated in Spain (wind and solar), that is, paradoxically, a problem. The problem is because current "green electricity production" is above 20% of total energy production, which sounds great, yes, the problem comes from nuclear power being dismantled from past 20 years, so the electric bill goes up because of the more expensive production (the solar energy production is specially expensive, which has been subsidized ad nauseam). Now the country faces near 19% unemployment rates (almost twice the U.S. figures), paying a huge price for energy, with the country in the middle of its worse recession since the post-war era (40's).
    • by turing_m (1030530) on Sunday November 08, 2009 @04:57PM (#30025536)

      Sooner or later everyone on earth is going to have to bite that same bullet. Unfortunately, virtually every society in the world has chosen to squander their energy resources on building convenient, cheaper, but generally and often highly energy inefficient infrastructure. Reconfiguring everything now that it is built is going to be difficult, expensive, and a kludge to boot. That's what we collectively get for being morons who often don't think beyond the next quarter let alone several generations ahead.

    • Most of the subsidies have been cut (which is why the install rate of solar power stations has plummetted), and the money paid is not all a subsidy (to start with, the government doesn't pays it and the taxpayers money is not touched). In spain solar and wind power is 0 in the "power market", and the power distribution companies have to pay solar and wind energy at a prices the government has set. If there was a free market there wouldn't be any price set by the government, but the owners of solar and wind

    • wait, "red" translates to "power network"?

      • by faragon (789704)
        "Red" translates for "network", but the meaning of "eléctrica" in a non-literal translation fits better into "electric power", in that context.
  • by meerling (1487879) on Sunday November 08, 2009 @04:21PM (#30025226)
    My understanding is that the destabilization talk isn't about overloading a circuit breaker on one day, it's about massive fluxuation in available power over the entire generation time.

    Just think of this. You've now made something like 80% of your grid powered by wind. (They all have problems, but let's just look at wind.) You have a doldrum for a day or two, now you've gone for that time period with only 20% of your normal power, that's destabilizing.
    What if your windfarms are spead out over vast distances so they tend to have different local conditions. (Something like if you have them all over the USA.) In some ways that will help since no location is expected to be the same as the other, so there is an averaging effect going on. However, that averaging effect is limited by long distance power transmission issues. The grid isn't just a pull & dump system. It uses power to send power, and it needs to maintain what you could think of as electrical pressure, (V.W.A. formulas.) which is why you have all those transformers and sub-stations all over the place, they are one part of that system. So even in the distributed scenario, what if you get a situation like high-wind on the east coast, and calm conditions mid-continent, and dead west coast. Funny thing, the need for power didn't decrease anywhere, but only the east coast is generating enough for their area, some of the mid will be ok, others in brown-outs or black-outs, and the west coast would be mostly black-out conditions, except near the few remaining alternate power sources, assuming the grid demand didn't leach it out completely and blow the circuits. (The entire east coast USA was blacked out by a cascade grid failure, and it might happen again.)
    Of course having multiple sources of power helps offset this kind of issue. For instance, solar. But that would only help during the hours of light, and again, it needs to be within a reasonable distance of it's market/users.

    All this stuff is why intelligent power managers advocate a number of different generation schemes distributed over the area with clustering (when possible) near high draw locations (like big cities). And no power manager can rationally turn a blind eye to those methods that run 24 hours on demand.

    I agree that we need to expand our renewable resources type power generation, as well as move away from fossil fuels, but it's a tricky balancing act with huge penalties for dropping the ball, so don't trivialize it.
  • Regarding the grid.... Getting energy from there to here seems a problem. Isn't the problem with hydrogen fuel cells the fact that you have to have hydrogen in the first place (which takes energy?) I don't know the efficiencies lost via conversion (which would include the economics of transportation), but if solar or wind power was used to generate hydrogen, couldn't the hydrogen then be delivered to where it is needed, for use when wanted?
  • Ten years ago wasn't there talk about using renewable power to pump water up to higher ground and then release the water to generate electricity at a known rate with a known duration, etc. Turns unreliable power into highly reliable power with a little waste added into the process....

    • Re: (Score:3, Interesting)

      by JaredOfEuropa (526365)
      The plans are much older than that, in the Netherlands I remember a plan from the 80's called the "Lievense Plan" which consisted of a huge water reservoir into which water was pumped, and then used to generate hydro power. The original plan was to fill the reservoir with any surplus power, wind as well as nuclear (which was looked upon favourably at the time), the idea being to keep less power plants running at capacity 24/7, instead of building more power plants to handle peak hours.

      Recently scientist
    • what you are describing is known as pumped storage and it has been around for a long time but it isn't cheap and suffers from the same issue as regular dam based hydro (indeed it's usually done in combination with it) which is that there are relatively few sites that are both techincally good and politically acceptable.

  • There is a solution (Score:5, Interesting)

    by MikShapi (681808) on Sunday November 08, 2009 @05:22PM (#30025730) Journal

    As Danish Oil and Natural Gas (DONG) utilities clearly figured out - put a REALLY big (distributed) battery [betterplace.com] on the grid to soak up the power when it's available and re-feed it into the grid when it's scarce. Not only can they produce more of the baseline power generation from renewable sources, they don't have to PAY the Germans to TAKE their excess power at night when they can't consume it. They can store it instead, use it at peak hour when kilowatt price is insane and drastically flatten the curve. Problem. Solution.

    As an OT side-benefit, we get electric cars wrapped around said batteries. For what we already got used to paying for car's fuel, there's enough margin in the operator's plan to subsidize new cars for consumers (think free iPhone on a three-year-plan), we'll get a parallel 1-minute-battery-swap-station infrastructure to petrol stations to enable real (non-golfcart) electric cars to go as far as the stations reach (range limitation is station reach, not battery capacity/petrol tank) without hour-long-charges along the way, remove an entire country's addiction to oil, fix the environment by running every single car in the fleet off renewable, and actually allow everyone in town to plug their car in at 8AM without having the lights in office buildings go down (The 'Everyone owns a Chevy Volt' scenario), while not having to spend tens to hundreds of billions on new power plants to cater to the spike. (But hey, that's just a side benefit ;))

  • don't get me wrong i think making efficent use of wind energy is great. but to suggest this has solved the limitations of wind, is the kind of junk science that prevents alternatives to coal fired stations being be taken seriously.

    sure it won't be a common occurance that the wind slows down in multuple locations... but thats HOW disasters happen, all the unlikely scenarios line up and you get that perfect storm. and when your talking about the power grid it's an unacceptable risk.

  • One word: (Score:2, Funny)

    by robinesque (977170)
    Flywheels.
  • how much energy (Score:3, Insightful)

    by Ralph Spoilsport (673134) on Sunday November 08, 2009 @11:28PM (#30028740) Journal
    does that wind prediction system use? Including the manufacture and maintenance of the satellites? Take that value and subtract it from the total energy output.

    Wind has a high Energy Return On Energy Invested (EROEI) but it's not as high as many people think. Similar to nuclear. Sure: X kilos of U generate gobs of power, but building, maintaining, decommissioning, and dismantling the plant and its waste is very energy intensive.

    RS

  • by hyc (241590) on Monday November 09, 2009 @02:15AM (#30029652) Homepage Journal

    this weekend large portions of Spain suffered extended blackouts as a number of the electric company's network routers were overwhelmed by an unexpected surge of traffic. This was apparently the result of an article about Spain's wind-based electrical program being published on slashdot.org, and the ensuing traffic overload from attempts to access the power generation graphs on the public site...

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