Analyzes options using first-of-its-kind selection tool
Like many K-12 school districts, Perkins Local Schools in Sandusky, Ohio, was contending with an outdated and inefficient infrastructure. Its boiler plant, for instance, dated to the 1920s and was in need of an overhaul. Numerous building-envelope repairs were required to prevent air loss.
Along with improving its infrastructure, the district wanted to reduce its dependence on traditional energy sources and lock in a portion of its spending.
To help the district pinpoint the technology with the most significant environmental and economic drivers, Honeywell analyzed several options using its Renewable Energy Scorecard. The tool looks at six proven renewable technologies, providing a simple payback—derived from calculating tax implications, rebates, subsidies, and other incentives—for each.
Starting with fuel availability, the Scorecard showed an abundance of biomass—more than 141 tons of wood waste per square mile—in the surrounding area. Wind also appeared favorable, with an average velocity of 18.7 fps.
Heating degree-days far outweighed cooling degree-days, with an average air temperature of 48°F. This indicated a higher demand for natural gas for a greater portion of the year, biasing the analysis toward biomass.
Additionally, Honeywell identified state incentives that would help in financing the project.
Once all factors were combined and weighed against conventional energy rates, biomass thermal was shown to have the quickest payback (around six years), followed by wind (around 11 years), and solar thermal and geothermal (just under 20 years each).
Although the analysis showed biomass-generated heat would provide the greatest savings, a biomass solution would take longer to implement and require the district to negotiate a long-term contract for fuel. As a result, the district turned its focus to wind, which would allow it to take advantage of a micro-climate caused by winds from nearby Lake Erie and eliminate any fuel-sourcing issues.
Administrators decided to install three 20-kw wind turbines at the high-school/middle-school complex, with an anticipated output of 144,000 kwh per year. Based on those figures, the turbines would cover more than 11 percent of the electrical load at the complex and reduce annual carbon-dioxide emissions by more than 130 tons.
The district combined the turbines with 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 a year for 15 years. Thus, the work will not impact capital budgets or require additional taxpayer dollars.
The project is expected to generate operational and maintenance savings of around $56,000 a year without a reduction in maintenance personnel. And thanks to a state grant of $150,000, the overall cost of the turbines was cut in half.
Information courtesy of Honeywell.
For Design Solutions author guidelines, call Scott Arnold, executive editor, at 216-931-9980, or write to him at firstname.lastname@example.org.