Moonbeam power no help during heat wave energy ‘snapback’

Aug. 10, 2012

by Wayne Lusvardi

Green Power hasn’t been much help during the current heat wave. Especially bad have been the “snapback” hours from, about 7 to 8 pm daily, when demand exceeds the forecasted supply of power.  Green Power is, at best, a pricey luxury public good.

The state electric grid operator forecasts that California should have a surplus of about 10 percent — or 5,200 megawatts of extra power — to cover the estimated demand of about 47,000 megawatts of electricity needed to meet the heat wave from August 10-12.

But wind and solar power are producing only about 1,300 megawatts — or about 2.8 percent — of peak hour power needs from 3 to 5 p.m. during the heat wave.

And green power can’t be counted on if suddenly the wind should stop blowing or a dust storm should cover solar panels on desert solar energy plants. Despite all the hoopla about Green Power it is a pricey luxury public good ,at best.

Is California’s huge investment in green power — wind and solar energy — making any difference? And when California shifts to 33 percent mandated Green Power in the year 2020, will this pose a threat to the reliability of the power grid during similar heat waves or cold snaps?

Shut Downs and Outages Result in FLEX alert

Contributing to the crisis of the heat wave of the second week in August, 2012, is that the 2,150-megawatt San Onofre Nuclear Power Station is shutdown for repairs and an unidentified 775-megawatt natural gas power plant suddenly went down for unexplained reasons.  The San Onofre nuke plant remains offline with no scheduled restart date.

These two facilities roughly serve about 2.95 million homes.  This resulted in the state electric grid operator calling a “Flex Alert” to conserve electricity consumption on Thursday August 9 through Sunday August 12.  A Flex Alert is meant to prevent having to call a Stage 1 power emergency.

Most of the Flex alert reductions were absorbed by industries reducing their work, closing early, or going to night shifts.  Greenies may detest “smokestack” industries but it is mostly such industries that make it so homes can continue to run air conditioning during heat waves.

Green Power Generation on August 9 

The three stable sources of green power — geothermal, biomass, and hydropower — were producing about 1,500 megawatts on Aug. 9 (see second graph above).

The variable sources of green power — wind and solar power — were producing about 1,900 megawatts when it was least needed at 1 a.m.

At 8 a.m. wind and solar were generating about 600 to 700 megawatts of power.

At 3 p.m. — when peak power was needed most — wind and solar were only about 1,300 megawatts of the 47,000 megawatt peak load or about 2.8 percent.   Solar power production starts to drop fast while consumption is rising towards its peak.   This is not typically fatal to irrigating crops but it could be for other purposes.

Then there is the proverbial “snapback” of power demand about 7 to 8 pm. This is when demand typically exceeds forecasted supply of power as people turn on late night television to go to bed but air conditioners are still turned on.  Solar power at this hour is typically non-existent and wind power is mostly a late night and early morning phenomenon.

2020 crisis

There is a looming crisis for 2020, when the proportion of green power has to be 33 percent of the base load power sources in California by law. Base load power — the lowest level of power needed in a day — is about 25,000 megawatts on at 5 a.m. for August 10.

When air conditioning, then evening lighting, is added we reach a consumption peak. Peak power is defined as the highest demand required at a particular time. On Aug. 10 that should be about 47,000 megawatts of power per hour.

In 2020, thirty three percent of base load power on a day like August 9 would be about 8,250 megawatts (25,000 megawatts x 33 percent = 8,250 MW’s).

During a similar heat wave in the year 2020, the 8,250 megawatts of green power would equate to about 17.5 percent of total peak hour demand.  Today, the state electricity grid operator uses about a 10 percent surplus to meet any unexpected emergency demands on the system.

But what happens in 2020 when highly unreliable Green Power amounts to 17.5 percent of the power mix?  What happens when variable Green Power is greater than the backup power?  Will California have to add more expensive conventional power plants than it should need to just to have a reliable source of power?

Blackouts have increased 350 percent since 2007.

Hopefully, California will have a chance by 2020 to repeal or curtail its Green Power mandate.  But it may take more blackouts such as occurred in San Diego in November 2011 before the proverbial light turns on in the liberal mind of most Californians.


Write a comment
  1. Rob McMillin
    Rob McMillin 10 August, 2012, 09:46

    an unidentified 775-watt natural gas power plant suddenly went down for unexplained reasons

    Please tell me they don’t make them that small.

    Reply this comment
  2. Tax Target
    Tax Target 10 August, 2012, 10:38

    Yup, I admit it I turned my Honda generator off. I’m sorry that little thing caused a flex alert….

    Reply this comment
  3. Wayne Lusvardi
    Wayne Lusvardi 10 August, 2012, 10:59

    Readers should be aware “watt” should be “megawatt.” I will ask editor to correct. Thank you for catching this

    Reply this comment
  4. Wayne Lusvardi
    Wayne Lusvardi 10 August, 2012, 11:00


    This is great —- and the timing is PERFECT as everyone sweats and worries about the whole thing collapsing —- and FOR WHAT? For reduced productivity, increased expense (that we can’t afford), fears of unreliability, and having to obsess about something that shouldn’t even be a thought that crosses our minds in the course of a day, that we should be able to completely take for granted in the year 2012 in the United States of America, for crying out loud??
    What strikes me most about what you’ve written here is that like everything else these people do, their huge effort and obsession with wind and solar that consumes all our money and attention — and will only get worse — is like spitting in the ocean compared to the huge engine that ACTUALLY make things run. I mean, what solar and wind produces (at the wrong times) is a drop in the ocean OF THE SURPLUS CUSHION ALONE! – never mind 47,000 MW of expected demand.
    We simply CAN’T CONTINUE with these “green power” mandates. The numbers for their pittance of power are laughable. And by the way last time I checked hydropower isn’t even considered “green.”
    Excellent point for the ‘corporate haters’ – amongst many:
    Greenies may detest “smokestack” industries but it is mostly such industries that make it so homes can continue to run air conditioning during heat waves.

    Reply this comment
  5. Bob
    Bob 10 August, 2012, 13:05

    Here in Colliefornia if you put up solar panels and generate more electricity than you use can you sell the excess back to the utility?

    I’ve heard that PG&E won’t let you do this. You’d think that since we pay some of the highest rates in the country and our rulers want us to use “green” energy they’d do everything they could to encourage people to generate and sell excess capacity to the utilities.

    Reply this comment
  6. Rex The Wonder Dog!
    Rex The Wonder Dog! 10 August, 2012, 16:47

    Where I live you can sell unused solar power back to the utility-don’t know what the formula is or if it is viable.

    Reply this comment
  7. Bob
    Bob 10 August, 2012, 21:52

    Mr. Wonder Dog, who is your utility? Is it PG&E?

    Reply this comment
  8. EastBayLarry
    EastBayLarry 11 August, 2012, 08:41

    Could you put a legend on that second chart? I can’t really tell what it’s about with just unlabeled colored lines and a “Zero through 24” count on the bottom. Is that time? (0=midnight? 24 also?)

    Reply this comment
  9. Wayne Lusvardi
    Wayne Lusvardi 11 August, 2012, 16:26

    Mr. EastBay

    The horizontal axis of the table shows hours of the day (1 to 24)

    The vertical axis shows megawatts in increments of 100.

    The yellow line is solar power in megawatts per hour.

    The light blue line is wind power in megawatts per hour.

    The brown line near the bottom is constant renewable power from geothermal and biomass power plants — it shows that this type of power is relatively flat and regular.

    The next line up from the bottom is a dark blue line that is also relative constant from hydropower.

    The next line up is gray in color and reflects natural gas power which is also relatively constant.

    The only sources of power that vary greatly per hour are wind (light blue) and solar (yellow).

    The table is from the Independent System Operator – the state grid operator.

    The table stops at hour 16 (4 o’clock in the afternoon on Aug. 9) 

    Reply this comment

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