Installing a Solar Energy System
Publicado: noviembre 2010
Committed to reducing his carbon footprint and participating in the fight to mitigate global climate change, Rainforest Alliance climate initiative manager Jeff Hayward and his wife decided to explore the feasibility of powering their Washington, D.C. row house using solar energy. Here is an account of their journey through the process of installing the system -- from getting a government grant to subsidize the project to installing the equipment.
"We didn't know much about the process, but could see that our home -- like many in our Bloomingdale neighborhood -- was ideally positioned to capture solar energy. Still, few of our neighbors had adopted the technology.
The Washington D.C. government was offering grants -- covering up to 50 percent of all installation costs -- for projects demonstrating renewable energy in practice. Our decision to explore solar energy came about a month before the application deadline.
We turned to the specialists at Switch Energy, LLC, who agreed to help us with the technical details of the grant application as well as the actual installation. Here, a Switch Energy professional evaluates our roof to determine the ideal placement (orientation to the sun) for a small solar system.
In less than one month, we produced a 25-page grant application highlighting the environmental values, the costs and benefits of the system, and outlining the installation process. Here, a page from the application pinpoints the proposed location of the solar energy system.
Success! We got the government grant. Next we obtained electrical permits and we were ready to begin installation. In this photo, an electrician prepares to install conduits on the outside of the house to protect and carry wire from the rooftop to the electrical power panel inside our house.
Moving 300 pounds of expensive solar gear onto our roof proved a bit of a challenge. Bringing it up with a ladder seemed too risky, so technicians set up a mechanical lift to hoist up the panels and other equipment.
We worked with engineers to determine the optimal arrangement for racking the solar panels to the roof -- we needed a system that would remain secure in the face of powerful winds and that wouldn't compromise the stability of our roof. Ultimately, we decided to bolt steel I-beams to the brick walls of our house (raised about 2 feet above the roof). Switch Energy has since developed a more innovative and less expensive system using structural timber.
Panels were positioned to capture the maximum amount of solar energy year round.
We installed a total of six panels, which together can produce between 1,100 and 1,300 kilowatt hours (kWh) of alternating current a year. On long, sunny days these panels generate around 6 kWh of electricity and on shorter days, they average about 4 kWh. The amount of energy we buy from the grid is now about 75 kWh per month. All the rest we generate by the sun -- and what we don't use, we sell back to PEPCO, our local utility company.
Each panel was independently wired and all connected to a lead wire. If, in the future, we'd like to generate more solar energy, we have the option of installing additional panels.
We were concerned that installing the system could mean unsightly wires and other hardware coming from the solar array on our roof. We were pleased to learn that the conduit could be strung along a back corner through a narrow tube, so that it wouldn't interfere with the aesthetics of our 100 year-old Victorian home.
The process of turning sunlight into energy is still mysterious to me. Fundamental to the conversion is the inverter, which takes the direct current (DC) from the sun and turns it into alternating current (AC). The AC is sent to our power panel, and allows us to run any -- and all -- of our appliances when the sun is shining. Pictured here is the small closet in our basement where the inverter is housed.
Today, we have a fully functioning solar energy system, expected to last 30 years. We estimate it will cover 30 to 50 percent of our annual household electric usage, reducing our carbon dioxide emissions by 1,100 to 2,600 pounds annually. The only negative environmental impact of the system stems from its initial production, fabrication and transport. Our system -- including labor, materials and installation -- cost roughly $11,300. A comparable system would likely be cheaper today, thanks to new innovations and declining prices in solar energy design and equipment.