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Renewables Illusion

August 2, 2011

No matter the political spin, renewables are far more expensive methods for generating electricity than are coal, natural gas and nuclear.

Now, however, there is an effort to combine renewables, wind or solar, with traditional methods, such as coal or natural gas. It is thought that this will accelerate the adoption of renewables. A trial at Xcel Energy’s coal-fired Cameo Station in southern Colorado is an example.

Combining a solar plant with a natural gas plant, or wind power with a coal plant, or some other combination of renewable with coal or natural gas, will still result in expensive electricity.

When very expensive renewables are combined with inexpensive coal or natural gas, the end result is expensive electricity, it’s just simple arithmetic.

Here are some other facts that demonstrate that obtaining low cost electricity from renewables is an illusion.

The Electric Reliability Council of Texas says that less than 10% of total wind capacity is “available” during peak summer days.

Another regional transmission organization credits wind with a 13% capacity factor during peak periods. (The American Wind Energy Association claims a 30% or greater capacity factor for wind power.)

Solar is also highly variable. Look at a curve showing watts per square meter over the day in the Southwest and it’s easy to see that W/m2 starts at zero at dawn, increases gradually to around 900 W/m2, and then tapers off to zero when the sun sets.

There is also the drop in W/m2 when clouds cover the sky.

The variability of wind and solar means that expensive gas turbines must be kept spinning, ready to go online at a moment’s notice. This burns natural gas and emits CO2.

It’s estimated that 100 MW of gas turbines must be kept in reserve for every 400 MW of installed wind power.

Efforts are now being made to build gas turbines that can be started quickly so as to avoid having to keep gas turbines in spinning reserve. A 10-minute start is now being promoted by GE, Siemens and Mitsubishi, major makers of gas turbines.

While they avoid fuel use, they still require large investments in gas turbines to cover for when the wind stops blowing or the sun stops shining.

Why spend money on expensive electricity when it’s possible to generate cheap electricity using coal or natural gas?

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Additional TSAugust web sites:

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[To find earlier articles, click on the name of the preceding month below the calendar to display a list of articles published in that month. Continue clicking on the name of the preceding month to display articles published in prior months.]

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