California summer reserve climbs with new solar

OREANDA-NEWS. Additional solar generation and increased power imports should help California meet summer electric demand despite the lowest projected hydro generation in a decade.

The California Independent System Operator (ISO) projects summer demand will peak at 47,188MW, up by 5pc from the 2014's mild-weather peak of 44,703MW, but well below the state's all-time 2006 peak of 50,270MW, which occurred during extreme heat and stronger economic conditions.

"It is always a challenge to operate the grid under the high loads produced by sweltering summer temperatures, but our analysis shows we have the resources available to meet California's need this year," ISO president Steve Berberich said.

The ISO said the region's 2015 operating reserve margin, which includes generation outages and reduced hydro capacity, will be 25.3pc under normal weather conditions, up from 23.8pc last summer and well above a state regulatory requirement of 15pc. That is the highest margin since 2009.

Even under extreme weather, operating reserves should exceed 11pc, the ISO said, above the 3pc threshold when the grid operator must shed firm load.

The rising solar capacity is affecting power markets in southern California more than in the north, which in prior years depended more on hydro generation. NP-15 peak summer 2015 assessments are at a 16pc discount to the year-earlier prescheduled dailies. That discount is 24pc for the SP-15 hub.

California power demand has recovered slowly since the 2008 financial crisis. Growth has been further hindered by increasing rooftop solar installations, which at present amounts to about 3,000MW.

California's generating capacity from all resources totals 65,288MW, including 15,843MW, or nearly 25pc, from renewable resources. Two-thirds of the renewable total is about evenly split between wind and utility solar resources, followed by nearly 10pc geothermal and 8pc small hydro.

The grid has added 2,328MW of new generation over the last year, with solar resources accounting for 96pc.

California has 6,700MW of solar connected to the grid and 6,100MW of wind. The amounts should almost double in the next decade.

The ongoing statewide drought will limit hydro generation over the summer peak to the lowest in 10 years, at 7,428MW in August.

The 2015 hydro derate is 1,511MW in the ISO's base case and 2,733MW under current snow pack and precipitation conditions. Water storage at California's major reservoirs in mid-April was 48pc of capacity, 60pc of average and 96pc year-earlier levels.

The ISO said 1,840MW of demand response and interruptible load will be available this summer to reduce demand peaks, if necessary.

California relies on summer power imports to meet peak demand and more imports may be needed to offset unfavorable hydro output. Imports are projected to vary from 8,300MW to 10,100MW.

Unusually dry conditions put the state at a higher risk of wildfires that can knock out major transmission lines. The ISO identified Orange, Riverside, San Bernardino and Los Angeles counties as being at risk of localized customer outages due to wildfires.

"We will keep a close watch on the system, particularly in southern California where fires, high demand and transmission congestion can cause concerns," Berberich said.