Thursday, May 22, 2008

California wind fails again

David Walters has past on to me "2008 Summer Loads and Resources Operations Preparedness Assessment", an interesting summery of the operation of the California electrical grid system by the California Independent System Operator (CAISO).

The Report paints a damning picture of the unreliability of wind generated electricity:

Wind generating facilities are the fastest renewable resource to install and interconnect to the power grid. Wind generation presents enormous benefits as well as significant operational challenges. Wind generation energy production is extremely variable, and in California, it often produces its highest energy output when the demand for power is at a low point. During some periods of the year, wind generation is hard to forecast because it does not follow a predictable day-to-day production pattern.

Typically, during the summer, wind generation peaks when the total system load is low and is at
its lowest production levels when the total system load is high

Furthermore the reports shows that monthly average capacity factor of wind during periods of peak demand will reaches its maximum in January at 25%. The average monthly peak demand capacity factor for the other 11 month is under 20%. The the monthly peek demand capacity factor for wind
is under 10% four months a year and is only 2% for 2 of those 4 months. Despite its truly terrible performance California investors plan to add more than 4,000 MW of new name plate wind generation facilities, despite the worthlessness of such facilities to meet peek electrical demand, The only reason why investors put money into such facilities is because electricity produced by them is subsidized by the US Government. Because California needs reliable electricity all of the wind generators must be backed up fossil fuel burning generations plants, that must be constantly kept online burning fossil fuels in case the wind would drop. As a method of fighting global warming building more windmills in California is about as useful as licensing rickshaws in Los Angeles would be.

Update: David has a post on this subject at Daily Kos. He even quotes my post!


Mike V said...

The variability of wind can be dealt with (in California at least) due to the large amount hydro and combined cycle power plants. See the California Energy Commission report

"Intermittency Analysis Project" (

As for the fact that the wind does not blow consistently year-round, the same can be said of hydro. Some years are wet and some years are very dry, but they still use hydropower when they can. A kilowatt hour from wind is 2 kWh of natural gas saved. You do have a point that the true costs of wind is somewhat higher since combined cycle plants, hydro, and pump storage are needed to follow the electrical load. Concentrating solar with thermal storage could also help balance the load.

Charles Barton said...

Mike, there is a big difference between wind and hydro. Hydro is dispatchable, wind is not. Because water supplies are limited, hydro is reserved fro periods of peek demand. It is then used when it is most useful. Not only is wind not dispatchable, data shows that it is consistently not generating when it is most needed. If concentrated solar thermal with storage will produce power when it is needed, why would you spend your money on wind generation that won't. You are simply adding to the cost of the electrical generating system by building a redundant electrical generating system that wont generate electricity when you need it. Of course if the people of California want to waste their money on wind generation, more power too them.

Anonymous said...

Mike> Actually you cannot use combined cycle natgas burners to balance wind: they have too much of thermal momenta. You need to use single cycle plants for that, which further decreases efficiency.

DW said...

Well, my point is just the opposite, in fact you can use GTs, both the peaker type and the combined cycle type. The issue is that you HAVE TO use these fossil burning plants.

My plant is to use nuclear in my state for all base load power, or about 21,000 MWs and let all other forms, in the mean time, take up the over-baseload through peak power, which could include any source, EXCEPT wind because the capacity rating, *in California* is so low that it doesn't make it worth it to build withough huge subsidies. plan eliminates wind (but not CSP solar) but would eventually, by 2050, replace all power sources except hydro and geothermal, with LFTRs, which can be build smaller, safer and can load follow.


Mike V said...

Before I read the CEC report, I would've guessed that a combined cycle plant had a limited operating range. Say from 90% to 100% of the rated capacity. I was surprised to learn that this is not the case. In appendix B. of the CEC report it is mentioned that combined cycle plants have a power range down to 50% of the rated power. Moreover, it is claimed that new CC units can cycle down to 30%. Since appendix B. was prepared by GE Energy Consulting, I would assume that they knew what they were talking about.


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