With near triple-digit temperatures blanketing most of the state and coastal areas, California neared all-time peak loads for electricity heading up toward 50,000 MW on Thursday, meaning that natural gas sendouts were approaching summer records, too. Wind power was running low (973 MW), requiring more gas-fired generation to make up the load.
Electric loads were forecast by the California Independent System Operator (CAISO) to be near 48,000 MW on Wednesday but topped out at 46,257 MW. On Thursday they were edging toward that forecast, threatening to exceed the high for the year (47,196 MW), which occurred on Aug. 28 during an earlier heat spell.
CAISO said it has plenty of excess power supplies and it doesn't expect to hit the all-time peak load of 50,270 MW registered July 24, 2006 in the middle of what was then a regional heat storm (see Daily GPI, Aug. 25, 2006).
Last Sunday gas generated 315 GWh on the CAISO grid, a 30% increase from last Friday’s levels attributed to wind power sources falling to their lowest output in 151 days, according to a commentary by Genscape, a Louisville, KY-based provider of real-time commodity and energy market data and analysis.
CAISO’s own fall-off in wind generation matched a similar drop in wind power from the Bonneville Power Authority area from which CAISO imports.
"Gas’ increased share of the stack should be sustained [this] week as warmer temperatures are expected along with the potential for below-normal wind generation," the analysis said.
Sempra Energy's Southern California Gas Co. (SoCalGas) did not have complete sendout numbers for Wednesday, and it only has winter-summer peaks back to 2011. Its winter peak since then reached 5.1 Bcf on Jan. 14, 2013, and its summer peak was reached a year earlier when it hit 3.48 Bcf on Aug. 13, 2012. (In 2006, SoCalGas reported an all-time summer peak of 3.72 Bcf.)
In the north, Pacific Gas and Electric Co. (PG&E) expected a gas sendout of 3.2 Bcf Wednesday followed by 3.3 Bcf on Thursday as temperature were forecast to be as hot or hotter. PG&E's all-time record sendout was nearly 5 Bcf (4.975 Bcf) on a particularly cold day in December 2013, a spokesperson said.
PG&E's Pipe Ranger website (www.pge.com/pipeline/index.page) showed incoming supply capacity from all over western North American to far exceed any peak sendout the combination utility has ever experienced. For Wednesday and Thursday, the website was showing in excess of 6 Bcf/d of supply capacity from a combination of sources in western Canada, the Rockies, U.S. Southwest and Baja California in Mexico.
Even with the prolonged heat, which is expected to continue statewide until easing on Saturday, CAISO does not expect to call for voluntary electricity conservation, although it has issued a restricted maintenance alert to power plants through Friday, a spokesperson for the grid operator told NGI in Wednesday. "This ensures that we will have all operational [generation] facilities available [mostly natural gas-fired plants] to use or call upon if needed," he said.
The spokesperson said no fires are threatening parts of the high voltage grid, but wildfires remain "very worrisome." He added that there are no transmission or generation outages that could threaten overall grid reliability in the midst of a heat spell like the current one.
According to Genscape, in California wind power declines are typical this time of year. “Since 2011, wind generation in September has averaged 24% lower than August. Hydro output typically declines 17%; imports fall 8%; and solar output falls 2%. Load also declines 4% -- or an average of 32 GWh/d -- but the decline in generation from non-gas sources has historically been sufficient enough to enable total output from gas to increase 2% (or 4 GWh/d).”