Washington County government\'s first major solar installation is nearing completion, and officials say they are pleased with how the project is working out. Despite a projected 16-year payback time for the system, commissioners say the new array atop the county\'s Public Services Building in Hillsboro will serve as a model in the county\'s drive to make its buildings more economical and sustainable. \"There are more public policy issues at work here than purely economics,\" Commissioner Dick Schouten said. \"Then again, it doesn\'t sound as if sound economics are out of the question, either.\" Schouten referred to the manufacturer\'s guarantee that 25 years from now the system will still be putting out at least 80 percent of what it generates at startup. \"That\'s an additional 10 years of continuing to pay benefits,\" he said. \"It\'s still a good decision to make.\" The county is using money it received from the American Recovery and Reinvestment Act of 2009 -- the federal stimulus package -- to pay for the project. The solar system itself cost $375,000. The county spent an additional $424,000 in stimulus money reroofing the building. The latter expenditure was necessary because new solar installations are required to have roofs with 20-year-guaranteed lifetimes, said Candance Paradis, the county\'s facilities manager. The system is designed to generate an average of 67,000 kilowatt hours annually, said Scott King, an owner of Tigard-based Northwest Solar Solutions, which installed the array. By way of comparison, he said, a single kilowatt hour is enough to run a coffee pot or hair dryer for about one hour. King\'s company recently finished installing a similar system on Clackamas County\'s Development Services Building in Oregon City. Other recent installations include projects for Nike, Portland Public Schools and Willamette University in Salem. The 504 individual solar modules that make up Washington County\'s system are each about 20 feet long. They are extremely thin, lying virtually flat across the rooftop. The wiring and additional conduits needed to hook the system into the Public Services Building\'s electrical system should be completed by the first of the year, Paradis said. The final step is installing an educational kiosk in the main lobby containing a meter showing how much energy is being generated at any given moment. That should be finished by mid-February. At peak hours on slow days, the system could produce enough energy to make the meter in the building\'s lobby actually run backward. Such an event would create energy credits, which would then be applied to the county\'s electric bill as soon as the meter once again begins climbing upward.