On August 21, the first total solar eclipse to darken U.S. skies since 1979 will force utilities from Oregon through South Carolina to rely on contingency plans for an electric grid increasingly powered by the sun, according to a report this week by the Financial Times. Indeed, demand may increae by as much as 6,000 MW, FT said.
The moon’s umbral shadow will move west to east nationwide, starting at 9:06 a.m. in Madras, Oregon – with a total eclipse there at 10:19 a.m., Time Magazine states – and will end near Columbia, South Carolina at 2:44 p.m. local time.
As day turns to night, California’s grid operator, CAL-ISO, on May 1 estimated that demand would soar statewide from solar customer-operators. Demand is predicted to increase by 6,000 MW, enough power for the city of Los Angeles, as solar output nosedives.
The California Independent System Operator said the grid would lose 70 MW a minute as the moon covered the sun, then regain 90 MW a minute. That represents twice to three times the average “ramp rate” the grid handles.
CAL-ISO Manager Amber Motley said that the operator would reserve extra supplies of electricity from sources including gas-fired power p, according to the FT story. She called robust hydroelectric capacity left by heavy snows in the mountains “a blessing.”
Last year nearly 10 per cent of California’s net generation came from solar – up from 0.4 per cent in 2011, according to the Energy Information Administration. The state this year has been wrestling with an electricity glut during the sunniest hours, FT reported – forcing generators to pay utilities to take surplus supply and requiring some solar and wind output to be curtailed.
The North American Electric Reliability Corporation , the regulatory body, said the eclipse was unlikely to disrupt the continent’s bulk power system but urged utilities to study the effects and marshal generating resources.
“We don’t call it a reliability issue, but it’s an impact to the system operations and something operators need to do some planning to prepare for,” John Moura, NERC director of Reliability Assessment and Systems commented.