A series of explosions and fire shut down electricity generation at the world's largest solar power plant near here Wednesday. Thick plumes of black smoke spiraled into the clear desert air when one of four natural gas-fired heaters used to back up the solar heating system exploded. A short time later, a second natural gas heater caught fire and exploded as the first of 75 firefighters and 25 pieces of equipment were arriving at the site, about 140 miles northeast of Los Angeles. "We had a series of explosions, more than two," said Capt. Sharon Sellers of the San Bernardino County Fire Department. "Our first units got on-scene at 9:16 a.m. and a second explosion occurred at that point, then a series of them during the entire incident," Sellers said. "There was a mushroom cloud. The heat was real intense and there were explosions," said an inmate from the Boron Federal Prison Camp who was pressed into service to help fight the fire. He would not identify himself. Sellers said two workers at the plant suffered minor breathing problems and were treated at Barstow Community Hospital. Operated by LUZ International Ltd. of Los Angeles, the $280-million Harper Lake solar plant began generating electricity on Dec. 28 and produces 80 megawatts, enough power to serve 115,000 people. The company operates eight such plants in the California desert. Combined, they generate 274 megawatts, which is sold to Southern California Edison Co. An Edison spokesman said there was no interruption of electric service to its customers. "We had two oil heaters on line and were bringing up the third and fourth oil heaters when this explosion occurred," LUZ International spokeswoman Kathleen Flanagan said in Los Angeles. While no flames were visible 1 1/2 hours after the fire began shortly before 9 a.m., San Bernardino County firefighters had difficulty reaching the blaze deep within the generating equipment. "There is fire up there somewhere still heating that oil," Sellers said. The blaze was contained, but continued to burn late Wednesday. Cause of the fire was unknown, but fire officials ruled out arson and said it probably resulted from an equipment malfunction. While Flanagan said she could not immediately estimate the cost of the blaze, the Fire Department said a single natural gas heater costs $500,000. One was destroyed and a second was heavily damaged. Flanagan said the black smoke from an estimated 15,000 gallons of burning synthetic oil was not any more toxic than smoke from natural crude or refined oil and was not carcinogenic. But that report was disputed by Capt. Clyde Gamma of the California Department of Forestry and Fire Protection. He identified the synthetic oil as Therminol and said it is cancer-causing. Flanagan said the plant could resume generating electricity by Monday. But she said the backup natural gas-fired heaters would not be used. "We will be operating strictly in the solar mode," she said. For solar generation, large curved mirrors are used to concentrate the sun's energy onto synthetic oil, which flows through an insulated steel pipe. The hot oil boils water into steam that drives conventional electrical turbines. Sellers said LUZ International had a fire about two years ago at another solar plant at Daggett and that explosions continued five hours into the incident. Stammer reported from Los Angeles and Harris from Barstow.
At the world's largest solar power plant near Barstow, an explosion occurred Wednesday as third and fourth natural gas-fired oil heaters were being brought on line. One of the heaters, used to back up the solar heating system, exploded as a result of equipment malfunction and set fire to a second, which also exploded. Two plant workers suffered minor breathing problems. Fire and plant officials disagreed on whether smoke from the burning oil was carcinogenic. The Harper Lake plant is operated by LUZ International, which operates 8 such plants in the California desert and had a fire at another solar plant two years ago.