Guy Marsden and wife Rebekah of Woolwich plan to show others how to use sunlight year-round to power everything from an electric car to a toaster oven by holding an open house at their home as part of the Green Buildings Open House Tour October 13.

The tour, hosted by Massachusetts-based Northeast Sustainable Energy Association (NESEA) and with online tour support from EnergySage (www.energysage.com), will showcase hundreds of properties throughout Maine and the rest of New England. Participants can see first-hand how homeowners have used sustainable building practices and installed energy-saving devices to cut costs over the long term and to minimize impacts on the environment.

Marsden said his Enphase solar array was simple to install with a little help from some friends. The Marsdens launched into the solar project during the summer of 2009 by installing the first 12 of 29 total panels on the roof of the Marsden shop. 

“What's unique about this solar panel array is that each panel is connected to its own micro-inverter,” Marsden said, looking up toward the shed roof covered with rectangular black panels. 

Marsden is chairman of the Midcoast Green Collaborative, a volunteer organization in the Damariscotta area that focuses on supporting a sustainable economy. He testified before the Maine Joint Standing Committee on Energy Utilities and Technology in 2009 to garner support for renewable energy legislation. His testifying, as Marsden tells visitors, led ultimately to an investment in solar.

Marsden's solar array is unlike other solar panel roof systems that are wired together and connected to a large, single inverter that converts the DC voltage to AC power. Marsden said shading on any one panel in such systems, is “like standing on a garden hose” and can shut down an entire array.

Another benefit to Marsden's system is it allows him to monitor how each panel is doing from the comfort of his office, where power generated from the panels is recorded and displayed on his computer. 

In fact, Marsden can see from his home computer how his solar hot water system is working.

Marsden describes, in great detail, how their project began and continues today. The couple chose their home in Woolwich not based on which way their roofs face (they face south-west), but because they liked it for other reasons. 

That's OK, he said. The 32 volt photovoltaic solar panels they installed over time still save them money on their electric bill. Using the space on the roof also meant not having to use up three-quarters of their yard with a giant ground-mounted array. 

Since this system is tied to the electric power grid, the Marsdens lose power during a storm like everyone else; this is an automatic safety feature built into all of the inverters manufactured in the world, designed to protect the line workers. As a backup, the Marsdens use a propane-powered generator. 

He said solar arrays should be sized proportionate to a household's energy usage. While Maine homeowners don't get money back for feeding power into the grid, they can receive credits on future usage. The trick is knowing how much electricity a household uses and determining the number of solar panels needed.

There are a number of reasons for investing in solar power. Marsden said they took advantage of low prices for solar panels and were able to fund their solar project through low mortgage rates. Another incentive is a 30 percent federal tax credit for energy efficient consumer products, such as photovoltaic systems, solar hot water systems, geothermal heat pumps and small wind turbines.

Marsden recommended homeowners first determine how much energy they use and get an energy audit to see where energy savings can be made before investing in solar. 

To learn more about this process, visit www.arttec.net. There are hundreds of homes, businesses and public properties open for viewing during the tour. You can learn more by taking the tour live. Find out where the sites are at www.energysage.com or take the virtual tour online.