Net Zero Cities: Microgrids may keep key services running during inclement weather

Four local electric suppliers believe that using self-contained micro-grids could be one way to hedge fears of power outages from winter storms and wildfires as efforts continue to decarbonize the power grid.

The panel at BizWest’s Net Zero Cities virtual event on Tuesday included Justin Brant, the utility program co-director at the Southwest Energy Efficiency Project; Darren Buck, director of power delivery at the Platte River Power Authority; Milton Geiger, energy resource director at the Poudre Valley Rural Electric Association and André Gouin, a business technology consultant at Xcel Energy of Colorado.

Handling cold snaps

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Electrifying residential and commercial power grids briefly became a flashpoint in the national conversation in February, when a winter storm that brought temperatures near 0 degrees swept across Texas.

Generators in the state weren’t prepared for that level of sustained cold and were forced to institute rolling blackouts, leaving up to 4.5 million homes without continuous power or access to treated water. Approximately 60 people died.

While the manager of Texas’ grid said that renewable sources amounted to only 7% of its power during the winter and the majority of the blackouts were caused by non-winterized carbon-energy sources, proponents of fossil-fuel power sources pointed to pictures of frozen-over solar panels and wind turbines as the cause of the blackouts.

Brant said it doesn’t matter what the power source is in a major outage event, because outages that lead to blackouts are generally an issue of power demand overwhelming supply.

“There was not enough supply of electricity to meet the demand, so by implementing energy efficiency and bringing the demand down over time, it makes it easier to serve that load,” he said.

Micro-grids to the rescue?

One answer to the reliability question is distributed grids, or building power and transmission systems to supply energy to buildings at much smaller ranges compared to long-distance power lines or underground cables from a centralized generation source.

Gouin said Xcel continuously works on emergency preparedness and looks for potential break points within its grid, but there is always the possibility of a large-scale problem that puts the distribution system under duress.

The power provider is currently piloting small-megawatt battery storage systems with the cities of Alamosa, Denver, Arvada and Nederland at buildings that are considered critical infrastructure, along with Denver International Airport.

“99.9% of the time, the battery is there to provide grid services, things like system peak reduction, feeder demand reduction, and energy arbitrage,” he said. “And then that point 1% of the time, if there is a problem on the feeder, and we do lose power, then we transition to micro-grid mode, and power is restored from the battery.”

Geiger said PVREA is helping operate a microgrid to power critical infrastructure at Red Feather Lakes not just because there’s community support for the project and because the town is fairly remote, but because the mountainous region was impacted severely by last year’s wildfire season. Local authorities ordered power outages to protect firefighters trying to contain the summer blazes.

“It can also be we just have to shut down the system per the request as a fire is being addressed and as the firefighters are actively engaging the fire, so there can be outages and there can be extended outages in there,” he said.

While the current costs of building a microgrid for an entire community could be prohibitive with current prices, Geiger said the falling prices of clean energy sources will allow more towns to discuss how much local power sources they want to pay for along with their mix of energy from a power distributor.

EV demand

As electric vehicles become cheaper and more widespread, the power providers are already trying to lay the groundwork to have owners reduce the demand they put on the existing power load when they plug in their cars to charge.

Buck said some EV chargers are taking as much as 50 amps of continuous flow to charge a vehicle, an amount that would place significant strain on the local grid equipment at scale.

“You start adding up those numbers and looking at the transformers that are in the communities and things like that, and our distribution providers are going to have to have some investments to be able to support the entire community going EV,” he said.

Geiger suggested that surge pricing can act as an incentive to keep EV owners from plugging in during peak demand times, but that incentive signal can go only so far when it comes to something as personal as owning and operating a vehicle.

“We’re gonna have to defer to what the consumer preferences are,” he said. “This is transportation; this is something very, almost sacred to folks.”

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