Tuesday, November 01, 2011

Big Wind and Big Solar: Like Wrecking Balls to Economies and Power Grids

The UK is the latest government to pull the plug on the destructive green jobs boondoggle.

In the US, yet another solar power company has joined Solyndra in bankruptcy. The Obama administration is becoming known as the "bad bet presidency," as a result of all the crony deals the US president has made which have cost taxpayers huge amounts of money which the treasury does not have.

More on the Beacon Power Corp bankruptcy

Power engineers and grid managers agree that big wind and big solar are far more trouble than they are worth, power-wise:
... the disadvantage with [wind and solar] is they are unreliable, infirm sources of power and can cause huge volatility in the grid, especially during the peak period when electricity demand goes up by 15% to 20%. Unless new market instruments like time-of-use pricing are introduced to elicit demand-based response from customers, supplying renewable power to the grid on a large scale might not be feasible.

... the increasing penetration of variable renewable generation required to decarbonise electricity systems is magnifying power system volatility.... _Power-Eng

Big wind and big solar are "feel good" technologies that will kill economies and power grids unless they are dealt with realistically -- and kept limited to an extremely small proportion of a utility's inputs.

Small wind and small solar are a different matter, as long as they are managed by persons who know what they are doing, for users who are able to deal with the unavoidable intermittencies, fluctuations, and unreliability of the resource.
In addition to requiring a large amount of materials, labor and money for each small increment of energy generated, the output from wind-farms is erratic and unpredictable. Unlike a 1000 megawatt nuclear plant, which reliably generates over 900 megawatt-years of energy each year, a 1000 megawatt wind-farm could be expected to generate no more than 200 to 300
megawatt-years, because of the variability of the wind.

The variability of wind speed imposes specific limitations on the electric output of any winddriven generator. Below 7-10 miles per hour (mph), the wind is too slow to generate useful power. Rated speed for most machines is in the range of 25 to 35 mph. At high wind speeds, typically between 45 and 80 mph, most wind-turbines have to shut down to prevent damage.

...So, an electric power grid is a continuous delicate balancing act, having to match up each new demand for more electricity by increasing generation accordingly, and matching each turned-off light switch by correspondingly decreasing output from one of its power stations. The grid accomplishes this balancing by maintaining a good-sized “spinning reserve” of some reliable energy source, such as coal or gas. Of course, this is all done automatically, under the coordinated watchful eye of various human operators. But in that situation, having an energy source, such as a wind-farm, that on its own initiative doubles its output or cuts it in half from time to time, is seen as pure mischief. As evidence of this, note that it usually requires 24 hours or more to restabilize the grid after a blackout. If we had never heard of unpredictable energy sources, and we observed unpredictable surges into and out of the grid, we might reasonably suspect sabotage. It is easier to harm the system by scrambling the demand than by blowing up transmission towers.

Not only is a wind-farm’s output unpredictable, but what pattern there is, is often counterproductive. In much of the U.S., the wind is apt to be higher speed and steadier at night, when the demand is lowest. And the gusts are strongest in the spring and fall, when neither heating nor air-conditioning demand is in full swing. _TedRockwell PDF

More facts about wind energy

Al Fin has always supported off-grid home-scale wind and solar power. And until he learned the facts about big wind and big solar, he assumed that they were a good approach. But no longer. If you think your world would be a better place if big wind and big solar are forced onto utility companies and power grids, perhaps you should learn the facts as well.

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Blogger Ruby said...

Hey Alfin, I'm with you. Small scale solar makes sense, as does wind. But for large facilities, it doesn't appear to be a winner.

Check out my assessment called I Want to Believe

9:30 PM  
Blogger al fin said...

Very interesting article. Thanks for the link.

I'm probably even more pessimistic toward big wind and big solar than you are, on technological grounds. It was a big change for me over the past 5 years or so, and I was sorry to lose my enthusiasm for those big wind turbines and solar arrays.

But I have seen shiny fields of spinning blades turn into rusting fields of junk over a very short period of time. The maintenance on those things is prohibitively expensive, and no one will keep them up without the government subsidies.

Utility managers hate the things, as they start out with capacity factors between 20% and 30% -- but produce most of their power during non-peak hours.

Governments force the utilities to buy the wind power even if they don't need it. Utilities also have to build expensive backup generating plants to make up for the lack of power-on-demand, or dispatchable power, from wind farms.

Wishful thinking is no substitute for economical action. Particularly in a society that is drowning in debt already.

9:04 PM  
Blogger rbl said...

I think Ted Rockwell may have confused some units on his figures for turbine performance. The figures I've seen say the turbines start producing power at 5 mph, hit nameplate power at 16mph, and start to feather the blades and spill wind above that. Protective shutdown starts at 25 mph. The 45 to 80 mph speeds mentioned by Rockwell sound more like blade breakage and pylon knockdown conditions; this is getting into Cat 1 hurricane range.


4:16 AM  

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