Blame is being assigned at warp speed for the massive power outages on the Texas grid, but the most basic danger isn’t being discussed: Big grids by their nature are prone to big failures.
That’s not to say we should do away with large grids — they offer an efficient way to deliver power to many people over a dispersed geography. But as forward thinkers in energy have warned, big grids have Death Star-like vulnerabilities, so they benefit from the insurance of microgrids and distributed energy resources (DERs), especially as society’s reliance on electric power deepens.
We’ve seen sweeping grid failures before: Puerto Rico following Hurricane Maria and the Northeast after Superstorm Sandy, to name two in the last decade. Earlier, in 2003 swaths of the Northeast, Midwest and eastern Canada lost power in a cascading failure precipitated by a wire coming in contact with a tree.
This week Texas came perilously close to being the poster child for the kind of event grid operators exist to prevent: total collapse of a grid when demand for power exceeds supply, disrupting grid frequency.
If too many power plants fail, a cascade of failure can ensue. “If the frequency goes too low that in itself causes more generators to trip off line,” said Dan Woodfin, senior director of system operations for ERCOT, the grid operator for most of Texas.
ERCOT saw the threat quickly emerging as severe cold caused demand to skyrocket to historic levels and about 185 power plants failed under the extreme conditions.
Had the grid collapsed, the US’ second largest state may have been without electricity for months, according to ERCOT. So the grid operator instituted the rolling blackouts to restore balance. This act, coupled with power outages from storm damage, left millions of Texans without power in freezing conditions, some for days.
So the worst didn’t happen, but it was still pretty bad.
What is the problem with big grids, exactly?
“These systems are vulnerable to cascading failure when one component is challenged, and they are predicated on a narrow band of operating conditions,” said Duncan Campbell, vice president for project analysis at Scale Microgrid Solutions. “For example, the gas supply being taxed by cold weather in Texas has lead to ~25 GWs of generator failures, which caused rolling blackouts, which makes heat (both electric and gas) difficult to maintain, and also taxes water treatment facilities knocking out water and sewage, all while cell towers are down because they didn’t have sufficient diesel backup.”
Kay Aikin, founder and CEO of Dynamic Grid, describes the grid as “brittle.”
Read related story: Texas on the Verge of an Energy Catastrophe: How Microgrids are Helping
Kay Aikin, Dynamic Grid
“There are differences between dynamic systems and static systems. The current grid is very, very stiff, very brittle, and what you really want are systems that are flexible,” said Aikin, who is a full member of the Gridwise Alliance, which advises the US Department of Energy on grid modernization and architecture.
Computers offer an example of a technology that evolved over the years from brittle to distributed and flexible. Early computing relied on large monolithic machines that easily failed. Now computing is undertaken by a federation of small devices. If one fails the others pick up the slack. “The Internet is a prime example of a distributed system,” Aikin said.
She noted that microgrids create flexibility because they can be turned on and off to help balance the power grid.
In fact, microgrids did jump in to help out, but their numbers remain few in Texas, so the flexibility they offered was minimal.
See Microgrid Benefits: Eight Ways a Microgrid Will Improve Your Operation…and the World
So why aren’t there more microgrids?
In truth, microgrids are coming. Research analysts like Guidehouse are forecasting significant growth. But clearly it’s not happening fast enough, partly because of institutional inertia and partly because of the way utilities are compensated for energy improvements.
Matt Nyquist, Concord Engineering
“Utilities have historically been slow to react to vulnerabilities. Energy infrastructure is vast and improvements have a high price tag that ultimately gets pushed to the ratepayer, making them unpopular,” said Matt Nyquist, project manager for Concord Engineering.
Another issue, he said, is that utility decision makers look at the rate of return they will receive from any given capital investment. Often increasing production or services pencils better for them than microgrids. “This could change if weak utility services start disrupting the bottom line,” Nyquist added.
Scale Microgrid’s Campbell foresees energy customers moving ahead on their own to ensure electric reliability.
Duncan Campbell, Scale Microgrid
“If the large society-wide system is failing the challenge of retooling for uncertainty, distributed energy is likely to be an emergent phenomena rather than a planned one. Just like we’ve seen in California. People are taking matters into their own hands. To me, this is the great challenge of DERs: policymakers have the opportunity to harness the power of DERs and use them to deliver great societal benefits (as shown in the recent Vibrant Green Energy study), but if they don’t DERs are still going to happen, they’ll just be deployed in a hyper-atomic manner without regard for the larger system. This is a make-or-break moment for regulators to either embrace DERs or watch them chip away at the system. Everyone should be pushing for the former,” Campbell said.
How many microgrids in Texas?
Isaac Maze-Rothstein, research analyst for Wood Mackenzie, tracks microgrids state by state. He told Microgrid Knowledge that he’s following 269 operational microgrids in Texas, with a total capacity of just over 700 MW. “While most microgrids in Texas support commercial customers, we’ve identified military bases, universities, hospitals, senior living homes, grocery stores, military and critical water infrastructure that all have microgrids,” he said. Microgrids are used during this type of crisis as back up power for their customers who lose power. They also are used as grid resources. A facility may not lose grid power but choose to island from the grid anyway to take strain off the grid when demand is high. The microgrid’s onsite generators supply the facility with power during this period. Maze-Rothstein cited action taken by the Brooke Army Medical Center as an example.
For its part ERCOT said in a news conference this morning that the Texas grid is no longer operating under emergency conditions. Now the post mortem on the storm will begin.
“We’ll begin the process of analyzing and looking at the situation immediately,” said Bill Magness, ERCOT president and CEO. “There are legislative hearings scheduled for next week. We have an ERCOT meeting set next week to delve into this issue and look at what happened and look at what could be better. Texas can’t afford for this to happen again. There are a lot of ideas about how to make that different. We want to participate in the process of considering those ideas. If there are things different that we could do better, we want to hear about it.”
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