Although the state was not plagued by high temperatures and new wildfires this week, fires impacted air quality and one of the state\u2019s largest nuclear power plants. Late on Sunday August 14, a fire at Pacific Gas & Electric\u2019s Diablo nuclear plant in San Luis Obispo temporarily shut down Unit 2. A transformer, said to be the size of a small house, caught fire around midnight but was reported to be under control a couple of hours later. The incident was reported to the Nuclear Regulatory Commission as an 8-hour \u201cnon-emergency event.\u201d The fire \u201coccurred during a low load and we carry sufficient reserves to manage this kind of event,\u201d said Gregg Fishman, California Independent System Operator spokesperson. The San Luis Obispo Mothers for Peace warned that the incident could have harmed workers at the nuclear plant. \u201cCounty emergency planners and the public need to know the cause of this fire and how a repeat might be prevented, as well as what consequences to expect should another transformer blow up when workers are present,\u201d the group stated August 19. They expect to monitor the investigation According to Dave Lochbaum, nuclear safety engineer for the Union of Concerned Scientists, transformer fires can undermine the connection between the plant and grid. Lochbaum noted that earlier this year, a problem at a substation in Florida lead to a minor electrical grid fluctuation, causing both Turkey Point reactors to trip offline. \u201cThe increasing frequency of nuclear plant transformer fires will continue unabated until (a) workers are killed by a transformer explosion, or (b) the news media covers the story.\u201d In February 2006, the NRC issued a generic letter to plant owners regarding their concerns about factors reducing grid reliability. \u201cThe NRC\u2019s reaction cannot be discerned from that of a mannequin,\u201d Lochbaum added. Continued wildfires are not threatening the grid but are impacting human health. In the northwestern part of the state fires have created \u201cvery unhealthy\u201d air qualify, reported the California Air Resources Board August 18. \u201cParts of eastern Humboldt County and Trinity County have experienced unusually persistent smoky days this week.\u201d Particulate monitors are located in Orleans, Big Bar, Junction City, Ruth, Hayfork, Weaverville, Ft. Jones, Somes Bar, and Willow Creek. The highest energy use on the CAISO grid occurred August 18, when load rose to 38,100 thousand MW, well below summer time highs. Los Angeles Department of Water & Power highest peak between August 14-20 was 5,223 MW. The high demand occurred August 14. Loads for the upcoming week are expected to be normal for this time of year, according to the department. The energy peak for the Sacramento Municipal Utility District was 2,875 MW, when the temperature hit 103 degrees. The peak load, occurring August 15, was significantly below the 3,299 MW all time high in July 2006. Temperatures and load are expected to be lower next week.