ORIGINAL REPORTING: On the duck's 10th birthday, scientists still resist New Energy over-generation

On the duck's 10th birthday, here's how to keep it from eating the power system; In 2008, the Duck Curve revealed the high solar penetration threat; has it been met?

Herman K. Trabish, March 22, 2018 (Utility Dive)

Editor’s note: New Energy over-generation has increased since this story ran but work to make the grid more flexible in managing it have also accelerated.

A fat, slow-moving, 10-year-old duck threatens the U.S. power grid, despite the many engineering minds that have been and are still hunting it. Ten years ago, researchers began thinking about the impact of rising renewables penetrations on the power system. They noticed solar creates a unique challenge because it can take over for less variable generation during the day but fades just when demand peaks in the evening. Where solar photovoltaic (PV) penetrations rose fastest, power system operators and researchers saw increasing reason for concern. It led them to discover new levels of grid flexibility that are still taking shape. Graphs were derived by National Renewable Energy Laboratory (NREL) researchers in February 2008. Their paper's simulations revealed how supply and demand curves would be affected by a then purely theoretical high solar growth. By 2013, California was working toward its 33% renewables by 2020 mandate and California Independent System Operator (CAISO) engineers had done more detailed studies. They named the resulting graph the "Duck Curve" because the deep dip in midday demand for system power looked like a duck's belly when followed by a sharp evening demand spike that looked like a duck's neck and bill. ..

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On Feb. 18, California's duck had its fattest belly ever when minimum demand dropped to a record-setting 7,149 MW midday low. On March 4, the duck held its head higher than ever with a record-setting three-hour evening ramp of 14,777 MW. This is crucial because CAISO had projected no more than a 13,000 MW ramp and no less than a 12,000 MW minimum demand by 2020. The new numbers show the over-generation has gotten greater and the ramp has gotten steeper at much faster rates than the CAISO anticipated. This doesn't mean the duck will eat the power system. Forward thinking engineers are successfully devising ways to control its appetite by discovering new power system possibilities. The next solutions will come when demand response and flexible loads like electric vehicles and storage are more fully deployed to draw on consumer market forces to smooth the exaggerated midday rise in solar and evening drop-off…click here for more

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