Amidst the blackouts that came with Hurricane Sandy’s East Coast assault, a few islands of light and heat stood out. From the suburbs of Maryland and bucolic Princeton, N.J. to the hardest-hit sections of downtown Manhattan, microgrids -- building or campus-wide backup power systems that can disconnect, or “island” from the grid -- stood firm during the storm, proving their value in a disaster.
But don’t get too excited about seeing every building hooked up with generators, batteries and high-tech gear to allow it to power itself during everyday blackouts. It turns out that building true microgrids like these takes a ton of planning in advance, as well as ongoing fine-tuning of the system to make sure it’s working for the benefit of the building and the grid alike.
Take the U.S. Food and Drug Administration’s White Oak research facility in Maryland, which rode through two days without grid power on its own 25 megawatts of both natural gas-fired turbine and diesel generator systems. But the core of that generator mix, White Oak's four 4.5-megawatt turbine generators, weren’t turned on as backup, said Tom Glennon, engineering director for Honeywell’s building solutions business, which installed and operates the system. They're on all the time.
That’s because White Oak gets all its heat from its power generators, making them a central part of its all-the-time heating and cooling cogeneration system, he said in an interview last week. The same type of cogeneration system kept New York University’s campus partly running during the hurricane, and Princeton University’s 40-megawatt cogen facility kept 4,000 apartments, 35 high-rise buildings, townhouses, garages, three shopping centers and six schools running for nearly two days.
Not everyone can justify the cost of building a cogeneration plant into their campus, however. In the case of White Oak, the FDA is constantly performing critical experiments that it doesn’t want to see interrupted by even a momentary blip of grid instability, Glennon said. Indeed, constant clean power was one of the requirements written into FDA’s agreement with the U.S. General Services Administration, which runs federal properties, to move to the new facility, he said.
A true microgrid is much more than a backup power system, however, even if it also does that as one of its core functions. It also has to include real-time, on-site controls to match the microgrid’s generation and storage capacity to power use in real time, as well as some way to interact with the grid, Glennon said.
“It’s a highly engineered solution. That’s why you have to look at the project holistically,” he said. And, of course, unless it meets the specific needs of the customer, putting buildings or campuses under their own power is likely too expensive a solution in comparison to cheap and (almost always) reliable grid power.
Even so, the market for microgrids -- or at least, technology that supports some or all of the functions of a microgrid -- is growing rapidly. The military is a big customer, for both remote and in-building applications. But so are university campuses like U.C. San Diego and its groundbreaking microgrid project, as well as utilities like San Diego Gas & Electric that host microgrid projects.
Whether these new building-grid systems come with islanding capability (making them a true microgrid) or without it (making them more of a “virtual power plant” design) will depend on how valuable islanding is for the customer, Glennon noted. Startups including Viridity Energy, REstore, Powerit Solutions, Enbala and others control building energy loads in response to grid signals, not to isolate themselves from the grid but to support it while making money at the task. Energy services giants like Honeywell, Siemens, Johnson Controls, Schneider Electric and others are connecting smart building control systems to the smart grid, while smaller companies and startups like Spirae, Integral Analytics and Power Analytics (formerly EDSA) specialize in managing the self-contained, self-maintained power systems involved in the microgrid process.
At the same time, many buildings are finding they can use existing backup power systems for grid purposes, a specialty of companies from demand response providers EnerNOC to startups like Blue Pillar. Developing nations such as China and India, which have unreliable and unstable power, are seeing new markets for microgrid-type systems emerge out of the larger market for simple, old-fashioned diesel backup generators -- the same type of technology that still runs most backup power systems in the U.S. and Europe as well, by the way.Meanwhile, Japanese companies
such as Panasonic, Fuji, Hitachi, Toshiba and Sony are rolling out combinations of home energy controls, plug-in vehicles, fuel cells, solar panels backed by batteries, and other technologies to help the country deal with its ongoing power crisis. The same technologies are being tested in Europe and the United States as well.Making Microgrids Worth It, All the Time
Microgrids have obvious benefits when the grid has gone down. But where’s the economic benefit when they're up and running? First of all, it’s important to note that the grid goes out a lot more than most people realize. Momentary sags and surges on local distribution feeders is a common cause of breakdown and work stoppage at high-tech facilities like semiconductor fabs, research labs or data centers -- and a microgrid should include local power quality and smoothing features to make sure it’s meeting the customers’ needs.
Automation is also key. While White Oak manually took itself into island mode in advance of Hurricane Sandy, it’s also gone off the grid about a dozen times over the past year or so, Glennon noted. Sometimes that was for a planned outage, but other times it was in automatic response to grid instabilities, or wholesale power outages lie those that came after last summer’s “derecho” storms that knocked out power for regional utilities Pepco and Baltimore Gas & Electric.
Getting a whole campus switched over to on-site power is a tricky issue for microgrids -- though one that White Oak mostly avoids by always having its gas-fired generators up and running. More typical backup power systems rely on batteries, flywheels, fuel cells or other fast-acting power sources to carry critical loads, while local backup generators or microturbines are “spun up” to power larger loads.
At some point, fully functioning microgrids could sell their on-site power back to the grid -- but there’s got to be a compelling reason to get into the game. The FDA hasn’t used White Oak’s generation capacity to meet demand response calls for Mid-Atlantic grid operator PJM or bid its spinning reserve capacity into the regional power market, Glennon said, mainly because that’s not its purpose. But certainly a microgrid-connected campus could cap its own power usage to prevent expensive demand charges, or shift power usage to off-peak hours to avoid high peak power prices.
Nor has the White Oak facility been tied to any of the region’s wind or solar power systems, he said. Using microgrids to smooth out intermittent wind and solar resources could make that on-again, off-again power easier for utilities and grid operators to handle.