Plugging the Sun into the Grid

About the Author: Bill Clugston joined EPA’s Administrative Systems Division in 1991. Later, in 1994 he moved to the Region 10 Seattle office as a Computer Specialist in the Information Resources Unit. He develops software for Region 10 and occasionally develops an EPA national application.

Before joining EPA, I resolved to do my part on climate change by reducing my production of greenhouse gases. My family made all of the obvious changes – changing from incandescent lights to compact fluorescent lights, better weatherproofing, and changing to newer Energy Star appliances, but could we do more? I was familiar with photovoltaic power generation on my backyard observatory and my recreational vehicle, but neither of those systems reduced our household CO2 footprint. At this point, I investigated a grid-tie solar power system.

man on roof working on electrical fixturesmen raising solar panel to roofWhile experienced with electrical circuitry, I am not a certified electrician and I am definitely not qualified to connect power-generating devices into the power grid! Therefore, I went in search of a qualified solar installer. Fortunately, the time of my decision, coincided with the Solar Homes Tour making it convenient to ask other solar power system owners their recommendation for a solar installer. After selecting a solar contractor, he came by to do a site assessment to determine the location for the panels and to discuss my requirements. We decided on a 2-kilowatt power system composed of ten 200-watt panels and ten micro-inverters. The micro-inverters are a recent innovation in the solar power industry. The micro-inverters convert the direct current from the panels to 230-volt alternating current at each panel instead of tying all of the panels together into a single inverter. The one inverter per panel allows enhanced production when parts of the array are shaded and reduces the wire size required to carry power from the array to the power grid. System decisions completed, we paid the installer 80% down to order the system.

image of solar panels on roofBefore ordering the system, I removed one potential obstacle, our homeowners association. Our HOA turned out to be no obstacle at all! In fact, they were supportive of the project. The lesson learned here was send detailed information to your homeowners association. In the meantime, the system finally arrived in Washington State after surviving snowstorms on the way from California. System installation required two days and after a sign-off by the electrical inspector, the system was on the power grid. In case the readers of this post question how practical solar is in rainy Seattle, since system installation in late January 2009 total production is 25kwh of electricity and 42 pounds of carbon offset — not bad power production for a city known more for its mildew than its sunshine!