Battery storage to supplement variable power generation, enhancing flexibility
How United Power deployed eight battery storage installations across their service grid to address variable power generation and reliability.
Project overview
United Power, located in the Denver, CO area, wanted to create a faster and reproducible workflow. This improved workflow helped develop, build, and energize battery systems that would work on the distribution grid to both offset demand during high use periods and provide a cost-effective back up system. Resources interconnected to the transmission system take approximately four years to complete once a purchase power agreement is executed. United Power added eight battery systems totaling 78 MW, which were sited at the cooperative’s substations and online 18 months after contracts were completed. Siting energy storage generation on the distribution system reduced the anticipated project timeline by 2.5 years.
What challenge existed that the utility wanted to address?
The cooperative’s exit from a single generation provider required United Power to source a variety of power sources quickly. The co-op’s goals were to provide cleaner energy, retain high reliability, and build in price stability, while incorporating power sources that were locally produced.
What did the utility do to address the challenge?
United Power contracted for and deployed eight battery systems totaling 78 MW, which were sited at United Power substations. The battery systems allow the co-op to recharge batteries during low cost, low use periods and deploy energy when consumption is highest. It also is a source of back-up storage, providing additional redundancy on the United Power system.
Were alternatives considered? If so, what were they and why was the chosen project preferred?
Transmission interconnected energy storage resources were also considered. The driving factor for the decision to advance energy storage on the distribution system was largely due to risk mitigation. In addition to the timing, cost, and deliverability risks, reliability impacts were considered as well. Small distributed energy resources have less reliability impact when unavailable when compared to large scale generation.
How does the project advance decarbonization?
Energy storage is a key component to advance decarbonization efforts. Siting energy projects on the distribution system enables decarbonization efforts to advance sooner, more reliably, and more efficiently by reducing line loss.
How were communities involved in planning and/or implementation of the project?
Since batteries were sited at eight substations located in Adams, Broomfield, and Weld counties, local city and county officials were engaged throughout the permitting process. Numerous meetings occurred to educate planning board representatives on the value and attributes of energy storage. Additionally, United Power engaged with the local fire departments to consider the safety implications and develop an emergency response plans.
What has the utility learned through the project?
Distributed energy resources are necessary to meet aggressive near-term decarbonization requirements and manage rapid load growth. There is not sufficient transmission in place or planned to manage these challenges. Energy resource enhancements on the distribution system offer cost and reliability advantages for the communities and businesses the cooperative serves.
How was this project funded?
Investment Tax Credit Passthrough
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