Monday, October 1, 2012

Wind and Water...

I find many people to be woefully underinformed regarding wind power. The thing- THE thing, really- about wind power, is that from an engineering standpoint, the power generation factor of wind is... zero. I'm not saying that it can't help, I'm not saying that it can't work; what I'm saying here is that because of its reliability, it CAN NOT replace a single other source of electrical generation. It has to do with the way our power grid is set up- there is no electrical storage capacity in our grid system. This isn't (really) a knock on the engineers, because there is not really any great NEED for storage capacity. Our generation abilities have almost always been sufficient to the task at hand.

One of the properties of the electrical grid is that electricity tolerates incredible little variation. The direct relationship between volts, amps, and watts means that any variation in the supply system can drastically alter the supply of energy, and cause catastrophic problems if it does not remain in balance. I'll try not to bore you with the formulas, especially since I am not an electrical engineer, and will probably get some of this wrong. The long and short is, Watts (or VA) are equal to Volts multiplied by Amperes. The equation is simple- W=VA (which is why watts are sometimes referred to as VA). Wattage is a measure of how much energy is being used or provided. A 100 watt bulb uses 100 watts of energy. Most household appliances, with the exception of high load items, use 120VAC power (sometimes called 110, 115, 120V, which is due to the tolerance for very SLIGHT variation) the AC portion means Alternating Current, which is extraneous to our discussion at this time. Therefore, by our equation, a 100 watt bulb, at 120 Volts equals .83 amps. If available energy exceeds this, that's all well and good. However, if available current does not meet this number, things begin to shift. As load exceeds supply, voltage begins to drop. As voltage drops, amperage begins to rise. Another way to look at it is when amperage (or wattage) rises, voltage begins to drop. A bulb designed around 100W/120V (iow, .83A), will not be able to withstand the amperage of operating at 100W/80V (1.25A). Other systems are even more sensitive. Any variation in supply will put household appliances (an especially anything with a computer board) outside of their design parameters. Things designed around 120 V power, when supplied with 80V, have a tendency to run poorly or not at all, and can cause breakers to trip, fuses to blow, and wiring to melt (sometimes light on fire!). Variations outside the standard are NOT good for an electrical system.

How does this relate to wind power? Easy- wind power is variable. HIGHLY variable. In fact, generation from a single plant can vary anywhere from its maximum rated output to zero. If the wind dies down, generation drops to zero. Without a viable method of storage, this means its average electrical output, the number used for calculating reliability, is also zero. Wind power, without storage capability, can never be used as a sole source of electricity. In order to supply a full power grid, there will always need to be a secondary power source.

Well, then, Mr. Smartass, do we just abandon green energy and keep burning fossil fuels until we run out? No. I said at the very beginning that I was not contraindicating its usefulness. The difference is twofold. The first, as touched on already, is storage. There aren't enough batteries in the world to operate the United States, at full consumption, for a single hour (probably more like a single second). However, if enough people were to install some sort of consumer scale wind power AND A STORAGE SYSTEM, the average draw of each house on the grid would decrease, and lead to a direct reduction in the amount of electrical generation required. This would allow the power generation to be reduced (or, more accurately, would reduce the need to expand). Its ironic, but the best way to influence power consumption on a national scale is actually to diffuse the generation. As more and more gadgets enter our lives, and we continue to build and expand upon the power grid, an influx in solar and wind generation can reduce the need to build new or larger generation plants. However, without the ability to store energy, all this will be for nought. The gigantic wind farms one sees in many places here in the west represent the lease efficient implementation of wind power that I can think of. They are vanity constructions, federally subsidized generation plants with an average output of zero. Only be decentralizing the grid, and producing power locally, can real energy efficiency be realized, and truly 'green' energy be produced.


  1. Close, both excess and under supply are problems. For example if you're pushing more power than is desired by the system your frequency will go up. Eventually you slip a pole because the generator has become unbalanced. If you don't feel like reading what that means, your generation ability is currently now fucked and it's doing serious damage to itself.

    Something can happen in the opposite where there is a much larger power draw than can be supplied. In this case frequency decreases you will generate considerable excess heat from excess current. There are numerous other things happening within the machine doing damage as well, but that is another rant entirely.

    As for stored energy, we do actually have methods of storing energy with the dams. Most can turn their turbines into pumps. They back fill a reservoir and then use it later when demand is higher and they don't have an excess of energy. Again the problem with wind though becomes inertia.

    Synchronous machines are MASSIVE and they don't change speed instantaneously. The other problem is that any method of storing energy will not be 100% efficient, far from it actually, so the ROI on doing so is little to nill. The damns are actually about as close as you can get due to how efficient they are.

    As for battery storage, it can be done, there is a town in Texas where they have a giant bank specifically to run the town in the event of a loss of service. Now note the bank is massive and the town is not large by any means. But it has been done.

    As for decentralizing the grid, that has other issues with it that are considerably more complicated. Homes supplementing their own energy helps relieve stress on the system, however it create new protection problems at the distribution level.

  2. See, this is what I meant about getting some of it wrong- fortunately, Barron IS and electrical engineer, so he can straighten me out on stuff. I may not like the dystopian future, but I do love having interconnected resources. So yes, there are some storage capacities scattered about- but still, not on a scale to make wind a viable sole generation option. As Barron mentioned, a balanced system is a happy system, an unbalanced system is soon broken. The grid system doesnt tolerate energy sources that are as fickle as the wind... Thanks Barron.

  3. Amps only go up when voltage decreases in an inductive load, like a motor or ballast in a flourescent light, or in a power supply like a computer.

    A purely resistive load like an incandescent light bulb doesn't make the current go up when the voltage decreases.

    Having said that (details ARE important!) you are basically correct.