Eclipse a Test for Solar Energy

August 21, 2017

eclipsepath

Adjustment will be a pretty simple matter that most people will not notice.

Reuters:

HOUSTON (Reuters) – As Monday’s total solar eclipse sweeps from Oregon to South Carolina, U.S. electric power and grid operators will be glued to their monitoring systems in what for them represents the biggest test of the renewable energy era.

Utilities and grid operators have been planning for the event for years, calculating the timing and drop in output from solar, running simulations of the potential impact on demand, and lining up standby power sources. It promises a critical test of their ability to manage a sizeable swing in renewable power.

Solar energy now accounts for more than 42,600 megawatts (MW), about 5 percent of the U.S.’s peak demand, up from 5 MW in 2000, according to the North American Electric Reliability Council (NERC), a group formed to improve the nation’s power system in the wake of a 1964 blackout. When the next eclipse comes to the United States in 2024, solar will account for 14 percent of the nation’s power, estimates NERC.

For utilities and solar farms, the eclipse represents an opportunity to see how well prepared their systems are to respond to rapid swings in an era where variable energy sources such as solar and wind are climbing in scale and importance.

Power companies view Monday’s event as a “test bed” on how power systems can manage a major change in supply, said John Moura, director of reliability assessment and system analysis at the North American Electric Reliability Corp.

    “It has been tested before, just not at this magnitude,” adds Steven Greenlee, a spokesman for the California Independent System Operator (CISO), which controls routing power in the nation’s most populous state.

CISO estimates that at the peak of the eclipse, the state’s normal solar output of about 8,800 MW will be reduced to 3,100 MW and then surge to more than 9,000 MW when the sun returns.

    CISO’s preparation includes studying how German utilities dealt with a 2015 eclipse in that country. Its review prompted the grid overseer to add an additional 200 MW to its normal 250 MW power reserves.

“We’ve calculated that during the eclipse, that solar will ramp off at about 70 MW per minute,” said Greenlee. “And then we’ll see the solar rolling back at about 90 MW per minute or more.”

Power utilities say the focus will be on managing a rapid drop off and accommodate the solar surge post the eclipse. Utility executives say they do not expect any interruption in service, but are prepared to ask customers to pare usage if a problem arises.”We want to assure our customers that we have secured enough resources to meet their energy needs, even with significantly less solar generation on hand,” said Caroline Winn, chief operating officer at utility San Diego Gas & Electric Co.

In the Eastern United States, utilities will have more time to watch the results of their Western counterparts. PJM Interconnection, which coordinates electricity transmission among 13 states from Michigan to North Carolina, says non-solar sources such as hydro and fossil fuel can easily supplant the 400 MW to 2,500 MW solar loss, depending on the cloud cover.

Bloomberg:

It’s not often that power grid operators, utilities and electricity generators get such precise and advance notice about more than 12,000 megawatts of solar power supplies set to suddenly drop off their systems. And some are looking forward to it — as a means of testing plants, software and markets refined in recent years in anticipation of the day when renewable energy becomes the world’s dominant source of power.

The way David Shepheard, managing director at consultant Accenture Plc, sees it: The eclipse is the “forecastable dress rehearsal” for the grid of the future. It’ll be the perfect test, he says, “for operating the grid when the sun doesn’t shine and the wind doesn’t blow.”

Here’s a closer look at what utilities, power generators and grid operators will be watching as the eclipse plays out:

Perfecting Forecasting

Charlie Gay, director of the U.S. Energy Department’s SunShot Initiative, expects the eclipse to provide instant validation for power forecasting models being developed. The department is working with the National Renewable Energy Laboratory and grid operators to improve software controls that balance supply and demand as the continent goes dark.

“It gives us a test for the models,” he said. Using satellite data and maps of solar plant locations, the group expects to be able to match forecasts with what actually occurs before, during and after the eclipse.

Grid operators including PJM Interconnection LLC and Southwest Power Pool are similarly using the eclipse to measure exactly how much rooftop solar is on their systems and improve their supply models for the next eclipse in 2024.

 

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4 Responses to “Eclipse a Test for Solar Energy”

  1. webej Says:

    Eclipses are more predictable than most disturbances. The effect is highly local, and probably somewhat more predictable than changes in cloud cover, or problems with other grid resources (transformers, sudden loss of a plant, problems with cooling and river water temperature, etcetc.). Solar varies across the day, and of course goes out at night. Nobody would be hyping this so much if we hadn’t already been conditioned so long about solar/wind cannot provide baseline power because they’re variable. Rainstorms could even “cancel” the eclipse “cancelation” of solar power.

  2. Don Osborn Says:

    Gee, surprise, surprise. The CA Power Grid survived the Great Solar Eclipse of 2017.

  3. redskylite Says:

    I seem to remember s similar air of excitement in Germany a couple of years back, and can understand for people working in this relatively new and growing industry, it would be a challenging and exiting time.

    I was pleased to read that free education is being offered for this exciting new industry.

    “Alison Launches Free Online Solar Energy Certificate Course

    The Ireland-based e-learning platform Alison, or Advanced Learning Interactive Systems Online, generally considered the first massive open online course (MOOC) provider, is making it easier for more people to get a basic education in solar energy with its latest launch.”

    https://cleantechnica.com/2017/08/21/alison-launches-free-online-solar-energy-certificate-course/

    • redskylite Says:

      And place a triangle in the middle of the “When The Skies Darken” graphic you nearly depict a great 1973 album cover.

      And all that is now
      And all that is gone
      And all that’s to come
      And everything under the sun is in tune
      But the sun is eclipsed by the moon


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