Plugging the Sun into the Grid
Posted on February 16th, 2009 - 10:30 AMAbout 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.
While 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.
Before 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!
Tags: electric, energy star, Solar Homes Tour
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Question of the Week
February 16th, 2009 at 12:50 pm
I am a graduate student at the University of Miami in an Environmental Health course. I understand that solar panels can function for upwards of 30 years and generate little waste for our planet today. Looking ahead to 2020, 2030, and beyond semiconductor, PV, and other toxic waste products produced by the retiring of older solar panels will increase. What are the EPA solar panel disposal techniques recommended today and is the EPA developing any solar panel disposal initiatives for the future like a recycling program? Thank you.
[Reply]
Bill Clugston reply on February 17, 2009 11:18 pm:
Hi Michael,
The good news about solar panels is most solar panel parts can be recycled. The aluminum frame, the glass in the panel, and the silicon in the solar cells can be re-used with existing technology. There is some lead in the cell traces and connections that would have to be reclaimed properly.
The other good news is we really don’t know the true lifespan of a solar module. The first modules built by Bell Labs are still operating after more than 50 years!
Bill Clugston
[Reply]
February 16th, 2009 at 1:57 pm
Bill, your system sounds great, but some price info would be nice. How much for labor and materials on your 2Kw system and what tax and other incentives did you find in your area? What’s your estimated payoff time and how do you calculate it?
[Reply]
Bill Clugston reply on February 17, 2009 11:31 pm:
Hi David,
The down-side of the blog is we need to keep the articles short, but, to answer your question, a 2kw system in Washington state costs $17,000 after incentives (not counting the Federal tax incentive). Sales tax is waived in Washington state on solar PV systems. Payoff is somewhere around 10 to 15 years depending on electric rates. Truthfully, I didn’t spend a lot of time thinking about the payoff — my goal was to aggressively lower my carbon footprint.
Bill Clugston
[Reply]