Sunday, October 14, 2012

Peeing your pants


I’ve been thinking a lot about wind power the last few days.  Firstly because the damn wind blows worse here in Nebraska than it does in Regina, and that’s going some.  But more importantly because every day I drive past this ridge that has been polluted with windmills.


This morning I happened to notice the old school technology right next door to the “modern” wind turbines and managed to capture both systems in the first photo above.  Clearly the old school technology is working well, judging by the cows gathered around the water trough in the photo below. 


I’m not so sure how well the more “modern” technology is working so this morning I did a little quick internet research and the results confirmed what I had suspected.

In the United States, domestic clean energy production and manufacturing competitiveness work hand-in-hand. The report finds total U.S. wind power capacity grew to 47,000 megawatts by the end of 2011 and has since grown to 50,000 megawatts, enough to power 12 million homes annually -- as many homes as in the entire state of California.

…. so trumpets Energy.Gov.  Sounds good doesn’t it?  Enough power for all the homes in California.  But a little common sense and some further digging reveals that it isn’t quite that rosy a picture. 

Energy production is subject to a variety of measures – capacity, efficiency, intermittency, reliability, dispatchability, availability and no doubt many more.  I’m not going to explain each of those terms – you can Google just as easily as I can.  The three important ones for me are capacity, intermittency and dispatchability. 

Intermittency refers to the times when power isn’t available from your chosen source – the lake goes dry behind the dam, the sun goes behind a cloud or the wind doesn’t blow.  Capacity derives from many of the factors above but in the case of wind a big influencer of capacity is intermittency.  If the wind doesn’t blow then you have zero capacity out of your wind farm.  And it turns out that results in capacity factors for wind in the neighbourhood of 30%.  Compare that with nuclear capacities that may exceed 100% of designed capacity.  And you get similarly high factors for steam (coal or natural gas) plants.  So only 30% of those homes in California will get supplied with power at any one time.  Maybe they’re used to that though – I hear they have become accustomed to rolling blackouts.

There’s another element to wind power though that’s more insidious.  When shills for the so-called green power industry gush about the benefits of their new religion they emphasize how we’re going to move from a world of dirty old coal plants to nice clean wind or solar power.  But are we really going to do that?  The answer is no and its due to the third factor that I said was important – namely dispatchability.

When we lived at Nipawin we were right between two huge hydro-electric plants which I was surprised to learn are controlled from over 200 miles away and are used as “peaking” plants.  That means that they get turned off and on in order to supply power during peak demand times.  When you look at the massive dam spillways and turbines its hard to imagine them starting and stopping but the reality is that they are well suited to that type of service.  If you’ve got a steam fired plant it needs to run 24/7 – it takes time to come up to full production and it takes time to shut it down.  Nuclear is just a steam plant with a different power source so the same rules apply for nuclear, coal and natural gas.  But with a head of water behind a dam and a turbine below the dam all you need to do to turn on the power is open the gates. 

So what has all that got to do with windmills?  I’m glad you asked.  Wind energy (and solar for that matter) isn’t continuous – its intermittent.  When you input that intermittent energy to the grid it may coincide with a period of increased demand in which case its all good.   However if that so-called green energy arrives at a time when the demand on the grid is constant then you need to take some other production offline and it turns out that the power that goes offline is hydro. 

The next time you hear some fool singing the praises of green energy ask them how it is that wind power is greener than hydro.  For me the whole green energy thing is like peeing your pants – it may give you a temporary warm feeling but with a little thought it quickly turns messy.

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