Finding the Green
Like many K-12 districts, Perkins Local Schools in Sandusky, Ohio, contended with an outdated and inefficient infrastructure. The district’s boiler plant dated back to the 1920s, for instance, and needed an overhaul. Numerous building envelope repairs were required to prevent air loss.
Along with improving the infrastructure, the district wanted to reduce its dependence on traditional energy sources. Perkins turned to energy services provider Honeywell to better understand the renewable landscape.
The company helped the district analyze several options using its Renewable Energy Scorecard, a tool which looks at six proven renewable technologies and provides a simple payback for each. The district could then work from a financial forecast based on tax implications, rebates, subsidies and other incentives for renewables such as solar, wind, biomass and geothermal.
The Scorecard for Perkins showed an abundance of biomass in the surrounding area — more than 141 tons of wood waste per square mile. Wind also appeared favorable, with an average velocity of 5.7 meters per second -- a desirable speed to economically generate electricity. Heating degree days far outweighed cooling, with an average air temperature of 48 degrees Fahrenheit.
Once all these factors were combined with available state financial incentives, the Scorecard ranked biomass thermal with the quickest payback (around six years), followed by wind (around 11 years), and solar thermal and geothermal (just under 20 years each).
However, finances weren’t the only driver for the district.
Blowing in the Wind
The analysis showed biomass-generated heat would provide the greatest savings. But a biomass solution would take longer to implement and require the district to negotiate a long-term contract for fuel. And school officials wanted their first renewable project to be as simple and visible as possible.
As a result, the district turned its focus to wind, which would allow it to take advantage of a micro-climate caused by the winds blowing in from Lake Erie.
Administrators decided to install three 20-kW wind turbines at the high school and middle school complex, with an anticipated output of 144,000 kWh per year. Based on these figures, the turbines would cover more than 11 percent of the electrical load at the complex and reduce annual CO2 emissions by more than 130 tons.
The district combined the turbines with the other conservation measures, creating a $2.1-million program. The improvements were funded through a performance contract with Honeywell that guarantees energy savings of approximately $136,000 per year over the next 15 years. In this way, the work won’t reduce capital budgets or require additional taxpayer dollars.
The project is also expected to generate operational and maintenance savings of around $56,000 per year without a loss of maintenance personnel. And, thanks to a state grant of $150,000, the overall cost of the turbines was cut in half.