Living plants rely on solar energy as their primary energy source, so why not a house? In July 2000, my wife Charleen and I set our sights on building a net zero-energy home. Our goal was to demonstrate that you can operate a comfortable, modern home—even in a climate challenged location—without burning anything.
At the start of the project, I was inexperienced in building design. But I had spent much of my career in biophysics immersed in numbers and calculations, working to quantify the exchange of energy and matter between sunlight, the environment, and plants. When I began running energy systems design calculations for our new home, I was amazed by how well my years of seemingly unrelated research had prepared me for the journey ahead. Along the way, we had to overcome some unique regulatory and technical challenges, but, in the end, patience and determination gave way to a carbon-neutral home that derives 100% of its energy from the sun and wind.
The motivation to build our zero-emission home came from the desire to reduce our contribution to global warming and pollution. That meant eliminating our home’s dependency on all conventional fuels. Homes with solar- and wind-electric systems commonly rely on natural gas, propane, heating oil or firewood for cooking, as well as water and space heating. We wanted to prove that it is possible to live in a home that offsets 100% of its energy with renewable, nonpolluting sources.
The first step was to find a location for our new home. Over several months, we came across four suitable properties in our home state of Vermont, but our potential neighbors were opposed to the notion of having a wind turbine in their backyard. Eventually we widened our search to the North Country of New York, where we found a beautiful, affordable property that met our needs—102 acres of forest and pasture, in Ellenburg, just north of Adirondack Park at 44.9° north latitude.
New York state’s net-metering law for residential RE systems allowed excess energy credits to be carried forward to the end of the annual billing cycle and supported property tax exemptions for the systems’ value. In addition, the New York State Energy Research and Development Authority (NYSERDA) offered generous financial incentives for both PV and wind systems. Based on some initial conversations, neighborhood support for wind generators seemed positive. I also learned that the town of Ellenburg has no zoning regulations that prevent erecting a 120-foot tower for the wind genny. Our project’s future looked bright. We closed on the property in October 2003 and were on our way.
Offsetting 100% of our energy needs would be no small feat given the cold, cloudy winters and humid summers in Ellenburg, which sits about six miles from the Canadian border. Key to our plan was a ground-source electric heat pump for space heating and cooling (see “Get Pumped” sidebar). Producing the electricity needed to run our heat pump—an estimated 7,400 kilowatt-hours per year—would require substantial RE generation capacity. And while our heat pump is also designed to assist in domestic water heating, we’d still need to generate about 3,000 KWH annually for our tank-style, backup electric water heater. Even though using energy-efficient appliances and lighting would help keep the remainder of our loads to a minimum, our annual electrical load still came close to 17,000 KWH.