Energy Storage

Storage with solar not yet economic, Austin Energy finds

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The value of battery storage combined with solar does not outweigh its costs in the Austin Energy service area, at least not yet, according to Austin Energy.

The finding is based on a preliminary analysis of the Austin Sustainable and Holistic Integration of Energy Storage and Solar Photovoltaics, or Austin SHINES, project, which is funded by the U.S. Department of Energy, the Texas Commission on Environmental Quality and Austin Energy.

The roughly $11.5 million project includes two 1.5 megawatt/3 megawatt-hours lithium-ion battery systems, multiple storage systems at residential and commercial properties, rooftop solar, a vehicle-to-grid component, advanced communications and a software optimization platform.

The four-year project is looking at best practices for integrating renewable energy and energy storage onto the grid at utility, commercial and residential scales, according to the public power utility.

Currently, adding solar and storage raises costs, according to the report. “This is not unexpected, as energy prices are relatively low and energy storage and local solar prices still relatively high,” Austin Energy said.

Electric Reliability Council of Texas nascent energy storage rules prevent systems of more than 1 MW from being used to calculate load reduction. This prevents utility-scale storage from being rewarded for its highest potential valued use, peak load reduction, according to the report.

Although only a few DER applications provide meaningful value at the present time, there is enough merit in the concept to continue developing and refining use cases and modeling values under current and future market scenarios, the utility said.

“Economic modeling results show that Austin Energy would be better suited to engage in ‘readying’ activities such as streamlining control system architecture, developing integrations for additional DER types, and developing tools to monitor key trigger points rather than engaging in wider-scale deployment of DERs at the current time,” the utility said.

Austin Energy found that voltage issues occur when DER penetration levels on the studied distribution feeders hit 40 percent, but the utility noted the maximum penetration level on the studied feeders is 6 percent.

“Until solar penetration reaches higher levels, there are areas that should be focused on other than solar reliability impacts to the bulk grid,” Austin Energy said. “To minimize financial risk and ultimately meet affordability goals, hosting capacity for individual resources and their locational impact and defining the value of reliability are proper areas for immediate work, rather than investment in assets to mitigate the impacts of high levels of solar.”

Looking ahead, there are several potential economic, technical and policy “tipping points” that could make major DER investments worthwhile, according to the report.

“Regardless of which tipping point(s) eventually sway the equation into the favor of DER deployment, it is up to Austin Energy staff to continue to research and understand the developments impacting their viability, and to position the utility for success in whatever scenario ultimately unfolds,” the report said.

The final SHINES reports will be more detailed, but its conclusions will likely match the preliminary report, according to Austin Energy.

Based on the SHINES project, the utility expects to continue to classify DER integration as a strategic initiative and intends to develop a roadmap for DER research, deployment and integration, according to the report.

Austin Energy said it intends to limit locally distributed battery energy storage deployments to research projects for the next two years unless a tipping point appears imminent.

The report recommends steering near-term DER investment into activities and equipment that are not prone to obsolescence because of evolving standards, rules, markets or technologies.

It also expects to rely on requests for proposals to gauge market readiness for large-scale energy storage.

DEED project

Meanwhile, a project funded by the American Public Power Association’s Demonstration of Energy & Efficiency Development program analyzed the ability of an Energy Storage System (ESS) placed at Austin Energy’s Kingsbery substation, near the La Loma Community Solar Project, to respond correctly and reliably to charge/discharge signals from a fleet-level controller.

Findings from the study completed by a DEED intern could help further develop the Distributed Energy Resource Management System (DERMS) used to optimize deployment of ESS assets, as part of the Austin SHINES project. The DEED intern involved in the project was Cydnie Golson, a mechanical engineering student at the University of Virginia.

“Through understanding particular errors in control system communications, this report will help public power utilities prepare for potential challenges and resulting solution discovery in deployment of an enterprise DERMS,” a final report related to the project noted.

“This internship successfully identified select barriers to the control system–ESS communications loop, effectively establishing areas for focused improvements. Furthermore, the analysis demonstrates to other utilities potential challenges to adoption and deployment of increasingly common (and necessary) enterprise DERMS,” the project’s final report said.

DEED members can read the full report in the DEED project database here.

To learn more about DEED membership Email [email protected].