California ISO forecasts record power use

The California Independent System Operator is forecasting a electricity demand will hit a record 46,245 Mw today, breaking the previous record of 45,884 Mw set July 12 last year. Southern California Edison spokesman Tom Boyd said the utility interrupted 2,400 Mw Monday, the maximum available in its portfolio of customers who receive discounts in exchange for having their power reduced during peak demand.


The California Independent System Operator is forecasting a electricity demand will hit a record 46,245 Mw today, breaking the previous record of 45,884 Mw set July 12 last year.

With reserves falling below 5% Monday, the ISO declared a Stage 2 power emergency and ordered the state's utilities to curtailing interruptible load customers. The agency directed Southern California Edison (SCE)to reduce its electrical load by 1,870 Mw�enough power to serve approximately 1.5 million homes.

Tuesday, SCE spokesman Tom Boyd said the utility actually interrupted 2,400 Mw, the maximum available in its portfolio of customers who receive discounts in exchange for having their power reduced during peak demand. Trouble on a transmission line Monday constrained power flow for most of the day, but Boyd said the problem was "looking pretty good" Tuesday.

However, he said, with record loads being forecast Tuesday, this could be the day that tests the system. Barring a change in the weather which has soared to triple digits, most observers expect the ISO to call for interruptions again today.

The California ISO has already declared Tuesday a power watch day because of continuing hot weather throughout the West. A stubborn high-pressure system, sitting over the western states for the fourth consecutive day, is expected to keep things hot for several more days.

The residual heat build up is increasing, causing air conditioning systems to work longer and harder to cool businesses and homes, according to SCE. At the same time, the supply of electricity is limited in the West because the record hot temperatures are pervasive across the region.

Should the situation worsen for any reason, and power reserves drop below 1.5%, the ISO will declare a Stage 3 emergency, the most critical status. The California ISO would direct utilities to "drop load," necessitating involuntary rolling, or rotating, outages for blocks of customers across their service areas until sufficient reserve levels are achieved.

Boyd said SCE has such a plan in place but it has never been used.

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