Southern California's electric power system is facing a number of challenges
heading into the summer peak demand season, largely because of the prolonged
outage of the two units at the San Onofre Nuclear Generating Station (SONGS),
which have been offline since January 2012. A combination of recent capacity
additions and electric system upgrades made since June 2012 will help meet peak
electric demand this summer.
The California Independent System Operator (CAISO), the grid operator for
most of the state, noted in its Summer Loads and Resources Assessment that
2,502 megawatts (MW) of capacity (capacity adjusted for planning purposes) have
been added since June 2012, with an additional 891 MW slated to come online by
June 1, 2013. The two off-line SONGS units, in comparison, total 2,246 MW.
This new capacity will help make up for the loss of the generation from
SONGS, but the reliability issue is more complicated than simply providing
replacement generation. Geographically, SONGS is in a localized pocket of
electric power demand near San Diego and Los Angeles. Given the characteristics
of the electric transmission system, the loss of SONGS limits the amount of
power that can be brought into the area over the transmission grid—rather than
generated locally—under some conditions. Much of the new capacity lies outside
of the San Diego-Los Angeles area, meaning that additional transmission upgrades
are needed to supply that area.
Southern California Edison also plans to
reconfigure the existing 220-kilovolt Barre-Ellis transmission line from two
circuits to four by June 15, increasing the amount of electricity that
transmission path can move. However, the region also needs local sources of
reactive power (a portion of generated electricity which is lost in large
quantities when transmitting power over long distances, i.e. importing power
from some of the new generating capacity to Southern California). Capacitors
will be added to several substations (see map above) by June 1, and two natural
gas-fired generators at the Huntington Beach facility will be converted to synchronous condensers by June 28.
Capacitors and synchronous condensers are commonly used to provide voltage
support in the form of reactive power to the transmission grid. All of these
system upgrades are designed to allow the system to bring more power into the
region.
The two units at SONGS have been offline since January 31, 2012 as a result
of mechanical problems currently being evaluated by Southern California Edison
and the Nuclear Regulatory Commission. Replacing the power from a low-cost
source of generation like SONGS already has changed wholesale electricity prices
in the state. Rising natural gas prices are likely to increase that effect in
2013. In its annual report, CAISO noted that 2012
wholesale power prices were higher than prices in the previous three years even
when adjusted for the lower 2012 natural gas prices. In addition, the unusually
large spread in
wholesale electricity prices between the northern and southern portions of
the state indicates system congestion. (DOE)
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