Schools have been one of the biggest institutional adopters of solar energy. Over 7,000 K-12 schools now use solar power, typically in the form of rooftop solar panels, which represents a 139% increase since 2014, according to the Interstate Renewable Energy Council.
Solar has become a good fit for schools for several reasons. Rooftop solar in schools is an educational opportunity to show renewable energy in action. There is also a strong economic incentive. Schools are some of the biggest energy consumers in the building sector. They spend more than $6 billion annually on energy, more than on computers and textbooks combined, according to the federal government’s ENERGY STAR program. Schools also are often dealing with tight budgets, so cutting electric bills is a straightforward and efficient way for schools to save money.
Now, schools should consider the next step as they strive to be leaders in clean energy: adopting battery storage to backup their solar arrays.
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As lithium-ion battery prices have plummeted and efficiency has increased, it has become a more and more common practice for large energy users that have on-site generation, like solar panels, to also have batteries. Some school districts have taken this plunge, particularly in places where distributed energy adoption is already strong, such as in California and Hawaii. But, likely due to a lack of flexible capital and the novelty of the concept, there are relatively few cases of schools adding storage to their solar arrays.
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The schools that take those first steps as early adopters will reap rewards, as shown by research in the Energy Storage Roadmap for Michigan, a project the Institute for Energy Innovation, the research arm of Michigan EIBC, completed for the Michigan Department of Environment, Great Lakes and Energy (EGLE) to examine the opportunities and supportive policies for the deployment of energy storage. Along with other large energy-using facilities like hospitals and hotels, secondary schools can realize strong lifetime savings for a combined solar plus storage project, the modeling for that report suggests. While the report was designed for the state of Michigan, the results are by no means only applicable to Michigan, and storage installations at schools have already begun to emerge in other states.
Peak demand is the biggest reason solar plus storage can save money for schools. Schools are big consumers of electricity, but this usage tends to be concentrated around specific times. As you might expect, with the school clock, through a normal week, energy use in schools goes through big peaks and valleys. From morning to afternoon on weekdays, when all the lights are on, computers are in use, TVs are on, and heating or cooling systems are running, energy use is high, but then in the evenings, nights and weekends, energy use plummets.
When it comes to the electricity bill, those peaks matter much more than the valleys because many schools pay a demand charge based on those peak times. That dynamic makes schools the perfect candidates to add storage. At peak times, the batteries can discharge electricity to reduce the peak demand and cut those demand charges.
A rooftop solar PV system on Lick Wilmerding High School in San Francisco, California. (Courtesy: mjmonty/Flickr) Storage also can help schools further “green” their footprint. Without storage, it’s a “use it or lose it” scenario—energy generated by rooftop solar panels cannot be stored for later use. With storage, however, more of the renewable energy generated on-site is actually consumed on-site. Batteries can use solar energy to charge up, and then discharge at the times when the school needs electricity but the panels are not producing enough by themselves—say, in the middle of a cloudy school day. The school is then running on electricity generated by solar energy, instead of drawing electricity from the grid (which may have been initially generated by fossil fuel-burning sources). The batteries also provide another source of backup power, meaning the school does not need to wholly rely on diesel or gas generators when the local grid fails.
Our energy storage roadmap modeled what the long-term costs and savings would be for a typical school building with a 150-kW solar and 9-kW battery storage system. The school would save $20,000 per year, paying back the capital costs of $157,000 after just seven years.
But even with a quick payback period, installing an energy storage system is an investment that can be costly upfront. How can schools that are interested in energy storage overcome the initial capital cost barrier? Other states, such as New York, have implemented programs in which schools are eligible for cost-sharing grants for storage installations. Such programs should include additional incentives for schools located in low-income communities, in recognition of the additional cost barriers those schools likely face. Utilities can also play a role by establishing incentive programs or “Pay as You Save” programs where schools could pay back the cost of the storage system over time, eventually taking ownership of the batteries.
While most schools still do not have solar panels, more and more schools have been installing them at impressive rates. By adding simple incentive programs, states and utilities can make storage-plus-solar as big of a success in schools as solar alone has been. It’s an opportunity to cut down on electric bills while at the same time showing students renewable energy in action.
