Despite sustained drought in the Pacific Northwest and relatively shallow reservoir levels in California, the state?s hydro resources have managed to hold up so far this summer thanks to lower temperatures. Even so, as with the region?s susceptibility to fire, potential September and October heat could still play havoc with grid reliability. ?We?ve been very fortunate, weather-wise,? said Jim McIntosh, California Independent System Operator director of grid operations. As an example, he cited the Sacramento area, which is enjoying its most temperate summer since 1983. California has thus been able to effectively manage its watersheds and the flow of hydropower. McIntosh pointed out, however, that the state?s total electric demand has been higher?notwithstanding cooler days. CAISO has hit new load records five times this summer, though temperatures are on average six to seven degrees lower than in previous years. Regional load growth, usually figured at an annual rate of 3 percent, has jumped as high as 18 percent in areas such as Roseville, he said. Construction trends in the residential home market aren?t helping keep a lid on demand. ?They?re building large houses, and they don?t put in one air conditioning unit?they put in two,? he said. ?Those are things we weren?t planning for, and we have some catching up to do.? Though California hydro supplies have remained stable, the state?s other resources could be on uncertain ground in coming weeks. McIntosh noted that approximately 7,000 MW of resources could go on the blink right when high temperatures might be poised to resurface. Nuclear units?as yet unspecified?are headed for scheduled refuelings in mid-September, and the DC Intertie, which can move electricity into Southern California and is rated at about 4,000 MW of capacity, will go out of service for the rest of the year beginning October 1. The Sylmar substation, where the DC terminates in California, will be upgraded during that time. ?We?re not out of the woods yet,? McIntosh said. The state would not be able to call on the Northwest for excess hydropower should the need arise. Not only is that region in drought conditions, it is trying to set aside hydro to use during peak hours in winter. As a result, the practice of sending hydropower to California, or ?net schedule interchange,? has dropped off, McIntosh said. According to information provided by the on-line California Data Exchange Center maintained by the Department of Water Resources, few of the state?s reservoirs are near capacity. The biggest?Shasta Lake, able to hold 4.5 million acre-feet of water?contains 2.76 million acre-feet, only 61 percent of total capacity. Feather Lake, at 2.2 million acre-feet of a possible 3.5 million, is 64 percent full. (Figures are current as of August 1, 2004, and have likely decreased since.) The numbers improve somewhat when compared with actual averages. For example, Trinity Lake now holds 1,873 acre-feet and, on average, stores 1,993 acre-feet?meaning that it currently stands at 94 percent of its average water level. But the lake can contain a total of 2.4 million acre-feet, making for a 77 percent capacity figure. The state water department did not return calls before press time regarding the potential outlook for reservoir levels. According to CAISO spokesperson Gregg Fishman, if California were graced with unusually high rainfall this winter, watersheds would still need a little more help. ?Even if we have a good hydro year, we?re still behind the curve,? he said. ?It?s going to take a very good hydro year or a couple of good ones to get us where we want to be.?