Tough Summer for the Power Grid. But the Microgrids are Working
Severe heat and storms across the US this summer have strained the electric grid and caused extensive power outages. But the microgrids are working.
Consider what happened on July 20 in northeast and north central Wisconsin when a thunderstorm knocked out power to 240,000 customers, leaving 50,000 with no power for two to three days.
The outage was more than an inconvenience; it occurred as visitors from around the world descended on the area for the 2019 EAA AirVenture Show in Oshkosh.
“The economic impact of the power outages was significant. Businesses without power were not able to fully take advantage of this tourism spike, and many restaurants and grocery stores were also faced with lost inventory from having to dispose of temperature-controlled products,” said Renee Torzala, community relations manager for Wisconsin-based Faith Technologies.
But the Gordon Bubolz Nature Preserve, a 700-acre sanctuary and environmental center in Appleton, dodged the outage because it had installed a microgrid a year earlier.
Is the wedding on?
When the grid outage occurred, the Bubolz microgrid performed as designed, said Don Wingate, vice president, utility & microgrid solutions for Schneider Electric, which built the microgrid with Faith Technologies.
Good thing, too, for the two weddings booked at its lodge that weekend.
“Both Schneider Electric and our alliance partner Faith Technologies are thrilled the weddings were made possible and continued as planned with the support of distributed and sustainable energy,” Wingate said.
The Bubolz microgrid islanded from the central grid within seconds of losing utility power around 11:35 am. It then operated autonomously for about two and a half days — until around 11:40 pm on July 22 when grid power was restored, according to Caramy Biederman, electrical engineering team leader at Faith Technologies.
Nearly three million customers — six million people — in 16 states lost power, according to PowerOutage.US
The microgrid uses on-site solar, a hydrogen fuel cell, battery storage, microturbine and natural gas generator. The solar panels and battery did most of the work.
“The microgrid’s battery and solar solutions powered the site until the battery reached the lower limits of the state of charge. The microturbine then picked up the balance of site loads (around 1 pm), supplemented by the solar available,” Biederman said. “The majority of the outage operated on solar and battery. The excess solar production charged the battery and created hydrogen. The microturbine, battery and fuel cell provided power to the facility when solar was unavailable.”
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Home Depot stays in business during power outages
Meanwhile, Bloom Energy is reporting that its microgrids allowed Home Depot stores in New York to keep serving customers, as a heat wave knocked out power in July, even at one point darkening Times Square.
The Bloom Energy microgrids, which employ fuel cells, serve Home Depot stores in Brooklyn, Halfmoon, Saratoga Springs and Amsterdam.
Electric grids don’t like extreme heat for a few reasons. For one, thunderstorms commonly accompany the heat and lightning strikes can cause accidental outages. Hot weather spikes air conditioning use, creating extra demand for electricity. If the strain becomes too much, utilities may purposely shut off power to certain areas to protect the system.
And finally, hot electrical equipment is prone to failure.
“When you use more energy there is more current, more amps that go through the wires from the power plants all the way through to your home. When you have more amps, things get warmer — transformers, the wires, the splices,” said Chris Evanich, manager of microgrids at S&C Electric.
Utilities have methods to cool equipment – fans and water. But from July 19-23, the heat and thunderstorms were too severe. Nearly three million customers — six million people — in 16 states lost power, according to PowerOutage.US. Michigan, New Jersey, Wisconsin and Pennsylvania were hardest hit.
“I don’t remember a situation where we had 16 states have power outages from excessive heat,” Evanich said.
Averting power outages with utility microgrids
He noted that utilities can avoid outages using microgrids pre-emptively.
For example in Illinois, Ameren has a microgrid with the capability to go into what’s called “storm mode.”
When the utility anticipates extreme demand ahead, it can intentionally separate some of its customers from the grid, and instead serve them with its microgrid. In storm mode, the microgrid — an S&C project — activates, ramps up its generation capacity and charges its battery. By serving a swath of customers, the microgrid takes pressure off the central grid.
When new electric peaks cause outages, utilities often respond by investing in new infrastructure to avoid a repeat of the problem. This can be expensive for ratepayers. But some now turn instead to microgrids and other non-wires alternatives — pinpointed, less expensive ways to ensure electric reliability. In addition to microgrids, other non-wires alternatives include demand response, energy efficiency, load management, distributed generators and battery storage.
“The grid is designed to handle the peak. So if we exceed the peak, or have too many peaks, or the peak is too long, that’s when equipment fails. That’s why non-wires alternatives are a good tool in the toolbox for utilities to use,” Evanich said.
Oh boy. And then there’s winter
It’s not just hot weather that pains the grid. Extreme cold weather also can cause peak demand as homes and businesses turn up their thermostats. That too can lead to outages.
Evanich noted that the South escaped the sweep of heat-related outages in July, but it may not have the same luck this winter if it’s cold. The South tends to experience peak electric demand in the winter because so many buildings use electric heat. The peak usually occurs in the morning as people get ready for work.
“We saw the extreme highs up North. What happens this winter if we see an extreme of temperatures going low?” he said.
Such worries haunt grid operators with a US economy that is now Internet-based, and a future that looks increasingly electric as buildings and vehicles swap out fossil fuels for electricity.
“People are becoming more dependent on electricity, whether it’s North or South. So these are real issues,” Evanich said.
Do you have a story about a microgrid that kept the power flowing during this summer’s heat spells? Please post below or on our LinkedIn Group, Microgrid Knowledge.
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