On Halloween 2011, 4 inches of wet snow fell in much of Pennsylvania and New Jersey, resulting in downed trees and wires, with a power outage that lasted four days. That was the last straw for our all-electric, well- and septic-dependent household. We decided to pursue energy independence.
We contacted Penn Renewables to help us navigate the array of options available. We thought we would want solar electricity, but were uncertain about a wind-electricity option.
Penn Renewables set up an anemometer to measure wind on our site for a month before we settled on the final design. The wind results were borderline, as we had suspected. Paul Stepanoff, our engineer, suggested that we might want battery backup to seamlessly support critical circuits when we lose utility power. Further, he suggested that a wind turbine could be helpful during times when the sun wasn’t shining to keep the batteries charged. We liked the idea of a backup energy source, but we had a lot of questions about wind power. Is it efficient? Is it noisy? It has a lot of moving parts—is it hard to install and maintain?
Paul showed us the wind turbine buyer’s guide in HP143, where installers rated different wind turbines. For our zoning constraints and planned contribution to our system, the Xzeres 110 (2.5 kW peak rating) was the best balance between power, noise, and cost. This turbine was as quiet as low-rpm, three-bladed turbines can be, with good ratings from installers.
With a large, all-electric house that supports a well pump and geothermal heat pumps, we would need our systems to generate approximately 25,000 kWh per year. We selected Sanyo 220-watt modules, referring to the PV module guide in Home Power. By looking at our required circuits, we decided on four AGM 8A8D batteries for our battery backup, including an eight-position rack for future expansion. Since our backup needs were moderate, the engineer suggested splitting the system to cut costs. Two-thirds of the array is wired to the battery backup Xantrex inverters and the rest goes to the batteryless Power One inverter.
The PV system was commissioned in April 2012. A month later, we had our first 3,200 kWh on the meters! The wind system took a bit longer because we were the first in our township to install a turbine and needed a variance. Our installers were invaluable in helping educate the zoning board and our neighbors on the intended installation. The turbine was installed and operational by mid-September.
On Halloween 2012, a year to the day from our decision to implement this project, Hurricane Sandy ravaged New York, New Jersey, and Pennsylvania. We were without grid power for nearly six days—and without sun, as the nearly 1,000-mile-wide storm passed through our area. But, boy, did we have wind! The wind turbine kept our batteries charged every day of the storm. We only drained our batteries once during the six days, when we left the aquarium equipment on overnight when the wind died down. The solar output was very low during this period and would not have kept the batteries charged.
While our neighbors were adding gasoline to their noisy generators and having to find an open gas station (a challenge when there is no power) to refuel the generator every four or five hours, we had clean, quiet RE that required us to do nothing. The inverters in a battery system do all the switching automatically, so there was seamless startup when the grid power returned.
We learned an important lesson during Hurricane Sandy: System redundancy with various sources of renewable energy is important. Although the wind turbine seemed like a marginal portion of our system, it proved to be worth its weight in gold during this event. We are also looking at other options, like installing additional batteries for flexibility in our usage during outages. Practical experience of having a prolonged power outage taught us about our usage and battery management. Both our turbine and solar-electric array made it through the high winds unscathed.
Rebecca Brewer & Keith Snedeker • Perkasie, Pennsylvania