On December 24, 2001, about 1810 Pacific standard time, a Cessna T210M, N1309M, collided with power lines and landed in a vineyard about 1 mile south of Sonoma County Airport (STS), Santa Rosa, California, during a forced landing following a loss of engine power. The owner was operating the airplane under the provisions of 14 CFR Part 91. The private pilot, the sole occupant, was not injured; the airplane sustained substantial damage. The personal cross-country flight departed Lampson Field (1O2), Lakeport, California, about 1745, en route to Petaluma (O69), California. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot stated that he based the airplane at Petaluma, and flew his daughter to Lampson Field in the afternoon. During the preflight before departing Petaluma, he noted about 20 gallons of fuels in the left tank, and 15 gallons in the right tank. The pilot was cruising at 5,500 feet on the return leg and began a descent when he was abeam Santa Rosa. He was well past Santa Rosa when the engine began to run rough; the right fuel gauge indicated 5 to 7 gallons. He switched from the right tank to the left tank, which now indicated 10 to 15 gallons, and the engine ran smoother. He continued toward Petaluma at an altitude of 3,000 feet, but could not visually acquire the airport's rotating beacon. He tried to activate the pilot controlled runway lights, but still could not visually identify the airport. He decided to fly back to Sonoma County Airport. He could see the runway lights for runway 32 at Santa Rosa. The engine began to run rough and stopped, but he switched tanks and restarted it. He was in contact with the Sonoma County Air Traffic Control Tower (ATCT) and apprising them of his situation. He lost and regained power five times as he headed to Sonoma County Airport. As he approached the airfield, he advised the ATCT that he was not going to make the field. They advised him that a vineyard was south of the airport. The pilot could not see the landing area because of the darkness, but headed toward the dark field. He saw power lines immediately prior to touchdown and could not avoid them. He contacted the power lines, but successfully landed in the vineyard and stopped after about 30 feet of ground contact. The airplane sustained substantial damage to the fuselage. The recovery agent did not observe any fuel in either tank, and no fuel drained out of the fuel lines when they were disconnected during disassembly for transport.