We tend to think of colleges, and especially their students, as our future. We’re not only talking about the students themselves, who will become the next generation of leaders, but the actual campuses, and what we can learn from them about our electricity future. While the majority of the U.S. still relies on large-scale centralized electrical generation and long-distance transmission, university campuses are one U.S. sector that has embraced microgrid technology.
Rocky Mountain Institute recently explored why microgrids have been so readily adopted on college campuses. We discovered four underlying factors that many of these institutions have in common: district-scale central thermal plants and distribution, sole ownership, high reliability needs, and a long investment horizon.
Central thermal plants: Over a century of district heating
Surprisingly, universities have been leading the way in microgrid development since the 1890s. Over a century ago many universities heated their campuses with district heating from a local central thermal plant. This approach efficiently heats a cluster of buildings by avoiding the need for individual buildings to install and maintain their own boilers or furnaces. Those central thermal plants provided the launch pad for university microgrids.
As technology improvements permitted, many universities converted their original central thermal plants to combined heat and power (CHP) plants, enabling them to generate electricity as well as provide district heating or cooling. These CHP plants are capable of reliably generating large amounts of power at system efficiencies as high as 80 percent, compared to typical utility power plant efficiencies of about 30 percent. CHP plants are also great base load generators (in industry parlance), making it much easier to build a microgrid. This in part explains why university campuses started building microgrids well before the advent of solar photovoltaics.
This is exactly what happened at Princeton University when it needed to reinvest in its aging boilers during the late 1980s. Princeton’s 150 buildings were heated and cooled by a central steam plant and a chilled water plant. The university opted for CHP as a better option. Its cogeneration plant generates 15 megawatts of electricity, about equal to Princeton’s average daily electricity needs. A few years later it added a thermal energy storage system—a 2.6 million gallon tank of chilled water, which improves the efficiency of the system and offers greater operational flexibility.
Ownership: The benefits of being a large landowner
In most of the U.S., electric utilities hold a franchise for the exclusive provision of electricity in a defined community or service territory. Such laws were originally intended to constrain redundant infrastructure and limit monopoly power of the utility, but they also hinder market access for local distributed generators from selling highly reliable power to nearby users if that power has to cross a street or public right of way where the franchise has domain. Per Rob Thornton, president and CEO of the International District Energy Association, these regulatory policies are a primary roadblock to building or expanding a microgrid.
But on college or university campuses, we find a common owner that operates, maintains, and supplies heating, cooling, and electricity to 100 or more buildings. That aggregated scale is ideal for combined heat and power and a district energy network.
The University of California, San Diego—covering 1,200 acres and with 11 million square feet of buildings—has the size and complexity of a small city. The university’s 30 megawatt microgrid generates over 90 percent of annual electricity demand. UCSD has only one connection to the local utility grid at the transmission level, and it owns the high-voltage substation. The campus also owns and maintains all of its distribution wires and meters.
Harvard’s main campus, in contrast, stretches over 200 acres and comprises hundreds of buildings, many of which are provided electricity, heating, and cooling from the university’s microgrid and district heating system. Being the sole customer for the electricity it generates allows Harvard to maximize its generation potential to meet load based on time of day, day of week, and season of year. This also makes it easier for the university to incorporate renewable energy projects, such as its 590 kW PV array, a priority for the university as it works to meet sustainability goals. However, the university crosses many public rights of way in two cities and counties. It has been wrestling with the franchise issue as it looks to install additional co-generation and expand its microgrid to a greater portion of the campus.
Reliability: The importance of islanding
Much of the technology and many of the medical cures we use today come out of university research labs. For example, researchers at Princeton University are currently improving the production of biodiesel from algae, studying new superconducting and thermoelectric materials, and investigating cancer therapies. But what if these researchers were suddenly without power? For some, they could lose critical work all in a matter of minutes. This is one reason why universities so highly value reliable power, heating, and cooling, leading many campuses to turn to microgrids because of their unparalleled reliability.
When Superstorm Sandy hit the East Coast, much of Princeton’s campus stayed lit while the surrounding city was in the dark. Per Ted Borer, the university’s energy plant manager, it was largely business as usual, though with higher stakes: “The guys in the plant are just trying to do what they always do, keep the lights on and the engines turning. Now you do that with extra personnel, and a heightened sensitivity, because you no longer have a margin for error. But otherwise, it’s the same thing you do everyday.” The university designed the microgrid so the campus electrical system could become its own island in an emergency. “It cost a little more to do that,” Borer told us, “but I’m sure glad we did.”
Long investment horizon: Keeping an eye toward the future
The final advantage that really seems to tip the microgrid scale for universities is their long investment horizon. For most universities, geographical location is part of their identity. As such, facility managers can consider investments with longer payback periods, because they are confident the university will still be operating, in exactly the same location, 30 years down the road.
“Harvard’s older than the country,” says Bob Manning, director of engineering and utilities at the university. “We certainly expect our systems to be here for a long time.” With that kind of confidence, it’s easier for universities to make investments that may take longer than 10 years to pay back.
In the late 1920s, for example, the University of Texas at Austin faced the decision whether to add electricity distribution to its district energy system or allow the local electric utility to provide service to the campus. Carl Eckhardt, superintendent of the power plant at the time, wanted to act in the university’s best long-term interest. He wrote letters to the superintendents of other major universities, asking them about their campus infrastructure. Then, in 1929, the university installed steam turbine generators to provide campus electricity, a critical first step toward the microgrid it has today. Juan Ontiveros, the current executive director of utilities at the university, still has Eckhardt’s original hand-written letters at the plant. “We are the beneficiaries of the core infrastructure [Eckhardt] built,” he says.
Lessons for the rest of us
While universities have certainly taken the lead on microgrids, that doesn’t mean others cannot follow in their footsteps. Recognizing the four factors that makes microgrids attractive for universities helps us identify other facilities that are ripe targets for microgrid investments: large industrial facilities with CHP, established district heating systems that do not yet have CHP, and critical infrastructure such as hospitals and military installations, for example.
To further expand the microgrid market means looking at reducing or eliminating the barriers for actors that do not have the same investment horizons, reliability needs, or property advantage that universities do. This means working with utilities and regulators to revisit franchise laws, and helping technology developers lower the costs of microgrid infrastructure.
In many ways, microgrids present the ultimate challenge to utilities and regulators who have built their cost recovery practices and regulatory structures to support a system of centralized power plants operated by a limited number of actors. Unlocking the full potential for microgrids to support an energy infrastructure that is both more reliable and more sustainable will require innovation and collaboration from all the actors in our energy ecosystem.
A version of this article also appeared on Greenbiz.
Images Courtesy of Shutterstock.com.