While the solar PV system at Sk'aavgaa naay Elementary School in Skidegate, on Haida Gwaii has only been installed for just over a month, the savings are already accumulating. Environmental equivalents achieved include enough energy to power a TV for 14,706 hours, or to power 16 computers for one year. Total greenhouse gases avoided to date: 507.84 kg. But by necessity, these benefits were not the driving force behind why the school went solar.
"We have a lot of power outages in the winter here," says Steve Goffic, the school's IT Manager and Maintenance Supervisor, who led the solar project. "We have to plug sump pumps into a generator and someone sits there to let them run and checks to make sure the basement doesn't flood."
He wanted to look into a way to solve this inefficient and potentially messy way of dealing with intermittent losses of power, and decided that a solar PV system with battery back-up would be the best answer. With this scenario, the pumps are plugged into the solar PV system's battery bank, where extra power is stored from the collection of sunlight that is converted to electricity through the rooftop modules (panels). Energy produced from solar modules first fills batteries and then satisfies electrical loads within the school. Any excess electricity that the system produces is fed back to the utility grid for credits, through the Net Metering Program. When the sun is unavailable, the utility grid provides power to the school like a grid-tie system. When there is no power from the utility grid, during a power outage, power is provided by the system's battery bank. Once this system was decided upon for the school, Steve and the superintendent for School District 50, then set about applying for subsidy from the UBCM gas tax fund, which provides funding for BC local governments and other eligible recipients for a variety of capital and planning projects.
Steve says he hired Terratek Energy, the company that designed and installed the system, because of their knowledge of the area. "They were from the same coast and understood BC weather conditions," he says. "Once the funding was locked in I consulted with them and the implementation of the system went from there. They were great to work with, and it was a very enjoyable experience."
The final product is two separate systems, one solar grid-tie system and a 20 kWh sealed battery bank, fed by the utility grid, to run two sump pumps and the telephone and communications systems. The reason the battery bank was designed as a separate system came down to the simplest and most economical way of meeting their load requirements during power outages. Although the systems operate separately, the functionality is the same as a typical grid-tie with battery back-up system. And the energy savings from their solar installation can be seen in real time with the Power-One renewable energy monitor the school installed. "Absolutely everyone is addicted to the website and how much power we're producing, even on cloudy days," he says. "It gives the kids something to look at and associate with the panels on the roof, and it's showing the school that we're doing something beneficial here."
He says he's thrilled with the installation, especially after testing it in a mock power failure. "We've shut off the breakers and the pump kicks on, with everything working accordingly."