Microgrids Hold The Key To Keeping Power Flowing After Disasters, UT Officials Say

Wednesday, September 19, 2018 - by UT

Hurricanes cause problems, injuries, and even deaths in a number of ways, not the least of which is failure of the power grid.

In the case of Hurricane Maria, for example, the amount of time it took to restore power in the US territory of Puerto Rico became an international story. It was seven months before most power had been restored.

Power loss can be life-threatening in many ways—from hospitals and shelters losing the ability to run critical care devices to failed pumping stations exacerbating flooding to fires sparked by people trying to cook or provide heat.

But it doesn’t have to be that way.

Microgrid technology now being refined will make it less likely for power to go off and, if it does, allow it to be restored much quicker.

Researchers at UT and Oak Ridge National Laboratory have spent much of the past decade improving microgrid technology, helping make the systems more efficient, dependable, autonomous, and cost-effective.

“They are smaller, more localized, and much easier to control and repair if needed,” said Leon Tolbert, Min H. Kao Professor in UT’s Min H. Kao Department of Electrical Engineering and Computer Science. “If there is a loss of power we can get it restored in hours rather than weeks or months.”

Think of microgrids as backup generators for the full power grid. They unite to distribute power across a region, but if something threatens the system they can operate independently. So when a storm strikes a power plant, the grid goes into “island mode.” Each microgrid switches to focusing just on its own area so one plant going down doesn’t affect the operation of the rest.

Professor Tolbert points out that the benefit of microgrids means critical emergency services like hospitals, first responders, and emergency shelters can continue to operate without disruption.

“Microgrid stations aren’t just connected to the grid but also have back-up power sources for when the rest of the grid goes down,” he said. “It varies, but they can have solar panels, fuel cells, diesel, even batteries—whatever it takes to keep them running in their particular environment.”

Fueled by the outcry over the length of time it took to restore power after Hurricane Sandy, the Associated Press studied how long it typically took to restore power to customers.

They found that, on average, swaths of coverage areas remained without a functioning power grid two to three weeks after major hurricanes.

And these weren’t in rural areas but major global centers like New York, Miami, New Orleans, and Houston.

Professor Tolbert, along with joint UT-ORNL Governor’s Chair for Power Electronics Yilu Liu and joint UT-ORNL Professor Fred Wang, is helping change that.

“The big thing in the past has been the cost, but the price of materials has come down and solar panels, fuel cells, and batteries are becoming cheaper all the time,” Professor Tolbert said. “They are now practical. They just have to be implemented.”



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