January 8, 2019 Read More →

Colorado co-op sees big potential in battery storage

Energy News Network:

Jerry Marizza likes to think the Colorado electric cooperative he works at learned a lesson with solar power. “We had the attitude that it was too expensive — nobody would do it except the rich greenies,” said Marizza, coordinator for United Power Cooperative’s new energy program. “Well, we were dead wrong.”

And so Marizza spoke with a sense of humility but also determination as he led visitors on a tour of the co-op’s new battery storage project about 30 miles north of downtown Denver. The 16 lithium-ion batteries total 4 megawatts and 16 hours of storage, making the project the largest in the state. It will likely remain so until Xcel Energy completes installation of 275 megawatts of battery storage by late 2022.

United Power sees the Tesla PowerPack ESS batteries as the sort of low-risk gamble that it is well-positioned to take and should take. The co-op has 87,000 metered members, from homes in the foothills to fast-growing towns and cities north and east of Denver. The oil and gas industry is responsible for a third of the co-op’s load and most of the growth, a 50 percent increase in eight years.

The electrical distribution cooperative’s embrace of batteries, though, has been stoking tensions with its power supplier, Tri-State Generation and Transmission Association, which adopted a policy last summer capping the amount of battery storage members are allowed to have on their systems.

United, despite its early skepticism, wasn’t caught entirely flat-footed on solar. In 2009, the cooperative launched the first community solar project in the nation, allowing customers to buy solar capacity in lieu of rooftop solar. The co-op plans a similar “community battery” storage, allowing users to purchase a share of the battery system’s output to directly reduce demand charges.

Marizza and United Power began investigating battery storage three years ago, got board approval two years ago, and signed a contract with Tesla in late 2017. Crucial was Tesla’s warranty that the batteries will remain at 100 percent capacity for 10 years. Marizza expects they will decline to 70 percent capacity after 20 years. With savings of $100,000 a month, United expects full payback within eight years on the cost of $7 million to $8 million.

More: Colorado’s biggest battery a ‘gamble’ co-op decided it needed to make


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