Lexington, KY - When the Locust Trace officially opens its 80-acre campus along Leestown Road, it will be home to Fayette County Public Schools' first net-zero energy school. Net-zero energy means that the building operations will generate, over the course of a year, enough renewable energy to pay back the energy it takes from the utility company, thanks to the facility's solar photovoltaic panels.
"It's taxpayers' money we spend on these schools," said Susan Hill, lead architect on the project and a principal with the firm Tate-Hill-Jacobs. "Fayette County is very cognizant about wanting to be very wise about how they use taxpayer money. Life cycle costs are considered on any kind of change that they make in products and materials, and the photovoltaics, until just the last year and a half, really did not quite meet that test. But it absolutely does now."
Hill explained that in recent years with photovoltaic panels, which have a 40- to 50-year life-span, it would take 90 to 100 years to recoup the cost. Hill said that such an investment didn't make financial sense for the district. Things have changed. Now, Hill said, payback time on photovoltaics has shrunk to 18 to 20 years.
"With the life of the product at 40 years," said Hill, "then obviously it's a no-brainer that it has finally become a fiscally reasonable thing to do."
"Kentucky Utilities initially did not have a system set up to buy back energy," said Hill. "Just within the last year, they have established such a system. Whenever the meter is running backwards, renewable energy will be fed back to KU to be distributed to other customers."
The school will be payed back with credit, which Hill said will greatly accumulate during the summer months. Because energy costs fluctuate, Hill doesn't know if it will balance out as net-zero cost, "but certainly (it will balance out) as net-zero energy use," she said. She also noted that the cost of photovoltaic panels has dropped. Things will only get better for the future of solar energy, she said.
To put into perspective the Locust Trace campus energy profile, Isaacc Fedyniak, the project's engineer, who is with CMTA Engineering, explained that the average U.S. school building consumes 72 KTbUs per square foot per year. The Athens-Chilesburg Elementary School in Lexington was the first Energy Star school building in Lexington, and it consumes about 42 KTbUs per square foot a year. The Locust Trace complex is designed to consume 16 to 18 KTbUs.
Approximately 600 Sunpower 305 photovoltaic panels will be mounted on two buildings.
"We are using the solar thermal not only for domestic hot water, but for heating the academic building and the greenhouse," said Fedyniak. "Thin tube radiators will dissipate heat into the classrooms and the lab areas."
Hill said the project has been in planning for about 15 months and is now under construction. A committee of district school leaders, educators and students along with the design team and involvement of advisory councils set goals and strategies for the project. They looked to principles and standards of the U.S. Green Building Council LEED program (www.usgbc.org), the Living Building Challenge (www.ilbi.org), Kentucky Green and Healthy Schools (www.green schools.ky.gov) and the American Society of Landscape Architects (www.asla.org).
"It's not that we are meeting all of those standards," said Hill. "We wanted to pull in all cutting edge ideas that are viable in today's marketplace."
Fayette County will not seek any certifications of the building but will engage ongoing evaluation and refinement of operational efficiencies and environmental impacts.
There will be a geothermal water loop HVAC system in place, but much of the facility will rely more on the movement of air by natural ventilation and large fans than on air conditioning to create comfort, said Hill. She said natural ventilation was an important factor in the building orientation on the land and the placement of operable windows. Sunlight exposure for natural daylighting and solar energy determined building orientation.
"Many of these sustainable ideas are not newfangled, strange ideas," said Hill. "They're really pretty ancient ways of doing buildings. We'd just forgotten some of them."
She also observed that technology has distanced us from the natural world and living with the elements. Rain gardens and permeable walkways and driveways will help return stormwater to the ground and water table. Waste management for operations that include hay fields, horses and livestock will direct different waste streams into composting, fertilizer, wetlands and possibly bio-fuels. A recycling program in partnership with Kentucky Pride (www.kypride.org) will work with Lexington's recycling center. The only water being brought in from the water company supplies the fire suppression water sprinkler system. Well water on the property meets all potable water standards and will be tested regularly.
Hill said there's a huge learning curve for end-users. Even with its automated, computer-controlled system shutting off lights and electrical circuits when not in use and switching things back on for a new day, success in attaining net-zero also depends on occupants being aware and cutting waste. In
the academic building entrance area, a 52-inch touchscreen monitor will give students access to real-time data on all of the building systems. It will show lighting loads, HVAC loads, plug receptacle loads per room, lighting levels and power consumption per room and more. The quantity of power generated by the PV panels as well as heat energy from the solar thermal will be shown. The display will include a weather station, monitoring sun, precipitation and wind conditions. Laptop computers that will be carted to different classrooms will also give students access to that data.
"I do think that the grassroots consumer is becoming much more sophisticated in asking questions and asking for these products and approaches, and I think that will drive the marketplace," said Hill.
She said she's seen sustainable developments on the West Coast that are selling well.
"It's reached a point where there's profitability in it," she said. "It's a marketplace issue. There are contractors in our community who are really stepping up to the plate with green practices for residential construction."