Schools have more zero net energy (ZNE) buildings than any other sector, except ZNE homes. As described in my recent article, Solar Schools 2024, there are almost 9,000 K-12 solar schools in the US. ZNE buildings go beyond solar.
In one year, a ZNE building generates with its own renewable energy the equivalent energy it consumes in that year. Typically, during some months a ZNE building is generating excess electricity that is supplied to the grid, other months a ZNE building is using electricity from the grid.
ZNE school buildings use 65% to 80% less energy than conventionally constructed school buildings, reports the U.S. Department of Energy (DOE). Remaining energy required is from renewables. In addition, zero energy schools can become community centers that educate a new generation of students with the science, technology, engineering, and mathematics (STEM) skills critical to our nation’s future.
Currently, children miss 14 million school days due to asthma and lung diseases. In ZNE buildings, reports the Rocky Mountain Institute, children are absent less and learn more due to better lighting, natural daylighting, and use of healthier materials.
For the Arlington County district in Virginia, architecture firm VMDO suggested a zero-energy school building, stating that it could be done within the existing budget. The school board approved a design for a zero energy building and then bid the renewable energy systems as an alternative. When the bids came in, the ZNE bid was one million dollars less than the original budget.
The resulting Discovery Elementary school is zero net energy, generating all of its energy consumption needs with 496 kW solar PV, solar thermal hot water, and geothermal heat exchange instead of traditional HVAC. The building is energy efficient thanks to exterior walls using insulated concrete forms with high R-value, high thermal mass, and good air sealing.
The school’s net-zero design is part of the school’s STEM interactive curriculum. Each fifth-grade student is required to complete a research project on a specific design aspect of the school. At the end of the year, the students are able to lead tours of the building for school visitors.
The Energy Lab at Hawaii Preparatory Academy is ZNE and the first K–12 school facility to achieve a “Living” certification through the Living Building Challenge (LBC) by harvesting at least as much energy and water as it uses over the course of a year, using low-impact building materials, and producing zero waste. The lab is great for learning, with strong use of natural lighting and ventilation. The science building houses classroom and meeting spaces for a school curriculum focused on renewable energy, and includes rainwater harvesting, onsite wastewater treatment, and a 26 kW photovoltaic array.
Learn more about ZNE school buildings, case studies, and resources at Better Buildings DOE. For ZNE school and all other building types, check out this New Building Institute (NBI) Database.
Locust Trace AgriScience Farm is a ZNE-certified technical high school near Lexington, Kentucky. In addition to preparing students with English, science, math, all the needed core courses, Locust Trace provides hands-on training in agriculture in spacious classrooms with adjoining labs, 6.5 acres for gardening, a state-of-the-art greenhouse with an aquaculture area for raising fish, an equine barn and arena, and an on-site veterinary clinic, all appropriate for the home of the Kentucky Derby. Roofs are graced with 175 kW of solar. Three separate zones are heated and cooled only as needed, using a dual-stage water source heat pump and an energy-recovery outside air unit. Since the building has much higher heating loads than cooling loads, a solar thermal radiant heating system is used and produces an average of 40,000 Btus a day.
When my grandfather grew up in Kentucky, it was a coal state. Now coal jobs are at their lowest in 120 years, with 5,000 working in coal mining. Yet there are 72,000 construction workers in Kentucky; high-performance building jobs are far greater than coal jobs. Kentucky is one of the few US states that still depends on coal for most of its electricity. Thanks to the ZNE leadership in schools, that may not be true in a few years.
For most school districts, it is easier to start with one ZNE building, rather than with an entire campus. It could be a library, environmental center, or district office building. ZNE is easier to accomplish in a new building than in retrofitting. As Arlington County taught us, ZNE may surprisingly cost less than the budget for a conventional building.
Look for government programs that help fund ZNE. For example, the DOE launched the $500 million Renew America’s Schools Program to promote the implementation of clean energy improvements at K-12 public schools across the country.
LED lighting uses only a fraction of the energy of older lights. Add low-cost sensors and controls, and lights are automatically turned-off when no one is present. Design classrooms to make good use of natural light and students learn more, have less behavioral issues, and use even less electricity.
Efficiency brings districts the fastest payoff using everything from LED lighting to better windows and insulation. Add advanced batteries managed with cloud services, and schools are actually making money.
With new buildings use passive design to orient the building for warmth in winter and cooling for hot days; more learning, less energy. HVAC demands are minimal in buildings with well insulated walls, roofs, and windows, and use of natural ventilation. With ground source heat exchange, HVAC can often be eliminated.
There are hundreds of ZNE school buildings today; there will be thousands of ZNE schools tomorrow.
Schools may eventually save billions that can go to better classrooms, more teachers and aides, and better learning. These clean energy advances have not only started with school district energy experts, they have started with city management, parents, and even students. It is time to get started.
