Over 6 million US students now attend one of 8,971 Solar Schools. I recommend this 15-page report – “Brighter Future: A Study of Solar on K-12 Schools, 5th edition.” This article summarizes some of the key findings and goes beyond the report to also include how leading solar schools use intelligent energy storage and energy efficiency.
Schools in the U.S. are spending $8 billion annually on energy, more than on computers and textbooks combined.
Installed solar power has expanded 400 percent in the last ten years in US schools. Almost 2 GW of solar capacity is installed in our schools. One reason for growth is that the capital expenditure (cap ex) barriers has been overcome with various third-party ownership models, including power purchase agreements (PPA), leases, and energy service agreements.
The report states, “As of 2024, 29 states plus Washington, D.C. have state policies that explicitly allow third-party ownership of solar through PPAs. Together, these states have nearly 11 times more solar capacity at K-12 schools than states that prohibit PPAs or have unclear policies. States that allow PPAs make up 92% of the cumulative solar capacity at all K-12 schools…”
California, New Jersey, Arizona, and Massachusetts lead in the number of solar schools. Hawaii leads in having 30% of all of its schools using solar; Connecticut 27%, Washington DC 24%. Minnesota, Maryland and Pennsylvania are coming on strong with innovative state-funded grant programs.
PPAs of 7 to 25 years are the primary financing method for school solar systems, allowing districts to avoid upfront capital expenditure. Hourly PPA rates are typically lower than utility rates, giving schools a strong incentive to install solar. PPA costs can be lowered with IRS Investment Tax Credit for 70 percent of solar projects and 50% for battery storage and ground-source heat pumps. Solar schools have been helped by the Inflation Reduction Act (IRA).
As Amory Lovins taught us decades ago, the best megawatt is a negawatt. Let’s go beyond the Brighter Future report and see how schools get more for less money with energy efficiency and intelligent energy storage.
In 2007, electricity use peaked in the United States. It has also peaked for schools. Smart and efficient buildings are having a big impact. In a typical school building, 30 percent of energy is for lighting. LED lighting uses only a fraction of the energy of older lights. Using the internet of things (IoT), lights are automatically turned-off when no one is detected by a network of low-cost sensors. Design classrooms to make good use of natural light and students learn more, have less behavioral issues, and use less electricity. Studies have documented up to 26 percent test improvements in natural daylight environments.
Heating and cooling demand 35 percent of energy in a typical school. More schools, like Hawai’i Preparatory, use good passive design to orient the building for warmth in winter and cooling for hot days, and make best use of natural ventilation. HVAC demands are minimal in buildings with well insulated walls, roofs, and windows. With ground-source heat pumps, older HVAC can often be eliminated. The IoT can enable greater savings, automatically adjusting temperature based on the presence or absence of people.
The Gordon-Rushville Public School District in Nebraska has a $5.8 million Energy Savings Performance Contract (ESPC) with Ameresco that upgraded energy efficiency at a high school, middle school, and elementary school. Retrofits included ground-source heat pumps, dual-pane windows, LED lighting, and the fixing of roofs and heat leaks.
My niece and nephew are graduates of the Poway Unified School District. The district of 41 schools installed 6.3 MWh of storage in a 10-year agreement with Green Charge, a company Engie acquired. The district was open to new solutions after saving $250,000 annually from new LED lighting, HVAC controls, and 715 kW of solar (contracted with a PPA) installed on modular classrooms in 16 campuses. For utility San Diego Gas and Electric, the energy storage at these two districts represent 13.7 MW that could be dispatched at peak hours as a virtual power plant.
Combining solar with energy storage allows schools to store excess solar power during the day and use it to meet peak demand in the morning and evening. Schools can generate revenue by selling excess solar power to utilities and wholesale markets during peak demand hours. Some states have net metering laws making peak-hour sales attractive for schools.
Add storage with solar, and a school has many ways to make or save money. Let’s follow the sun through the day to see. Many schools have peak energy use in the morning. Classrooms and offices are heated or cooled after being empty all night. Computers and equipment are turned on. Everyone arrives. For these peak hours, batteries are used, being fully charged in the middle of the night, taking advantage of deep off-peak time-of-use (TOU) rates.
In the middle of the day, a school can run on solar. With large-scale batteries, excess solar power can be stored. By late afternoon, energy demand declines at most schools enabling batteries to be fully charged. In many areas, peak utility demand is now the hours of 4 to 9 pm.
Pittsburg Unified School District, California, installed 1.6 MW / 3 MWh of energy storage at 10 schools. The batteries are paired with 2.3 MW of existing solar and could save the school district $2.8M over the 7-year agreement with MCE, a community choice aggregation, that is providing $715,000 to the school district. The school district receives up to $200 a month in MCE bill credits at each project site, a $0.22 per kilowatt hour credit for energy discharged to the grid between the peak hours of 4 to 9 pm.
Schools in many states can sell power to utilities and wholesale markets during these hours at premium rates, or participate in utility demand response programs where energy use is curtailed.
Saving on energy can be the difference between adding teachers or cutting some of their jobs; adding classrooms or closing schools.
Performance contracts and PPAs are types of public-private partnership where the public school avoids the capital investment and the private firm shares in the savings.
Clean energy companies and utilities are helping our nation’s schools move forward with clean energy, even when schools lack funds for capital expenditure, by implementing solar power, energy efficiency, intelligent energy storage, and demand response.
