Austin Energy staff reports 67% carbon-free load share, outlines transmission and battery expansions toward 2035 goal

Lisa Martin, Austin Energy's chief operating officer, told commissioners July 20 that the utility's fiscal-year-to-date carbon-free percentage of customer load stood at 67% and that the utility remains committed to a 2035 target of 100% carbon-free generation as a percentage of load.

Martin said the figure measures how much of customers' consumed energy is offset by carbon-free generation, not the share of total generation. "FY year to date, we're at 67%," she said, noting that Q1 and Q2 tend to show higher renewable percentages. She cautioned that load growth, congestion and curtailment remain operational challenges.

In a slide presentation and answers to commissioners' questions, staff highlighted progress across several implementation tracks. Martin said Austin Energy had 199 megawatts of local solar installed as of Q2 FY26 and roughly 16 megawatts of local batteries operating, with 140 megawatts in development and slated to come online by the end of 2027.

On utility-scale batteries, Pat Sweeney, interim vice president for energy market operations, described a planned centralized 200-megawatt, two-hour (400 MWh) resource and told commissioners the project will be dispatched by Austin Energy and is comparable in total energy to a previously proposed OCI battery that used two-hour duration.

Staff also described a battery demand-response pilot and a separate Base Power aggregation that gives Austin Energy dispatch rights for up to 40 megawatts of aggregated customer-sited batteries.

Transmission capacity was another focus. Martin said Austin Energy is advancing regulatory steps for a new 138-kilovolt line to increase import capacity by about 200 megawatts and is aiming for commercial operation in the 2029 timeframe; she added that later phases could upgrade additional lines to still higher voltages. "These types of projects help reliability, affordability, and clean energy objectives," she said.

Commissioners asked about the timeline for regulatory rules affecting capacity valuation (the 12 CP proposal), the potential for thermal energy storage, and how batteries and peaker plants interact. Staff said rulemaking is months away with an anticipated adoption in December and noted that batteries and peakers serve different operational roles; batteries can be dispatched across more hours and used for demand response, but peaker units provide capacity for particular grid conditions.

Richard Genesee, vice president for customer energy solutions, said Austin Energy is evaluating programs to reach medically vulnerable and low-income customers, including models similar to prior Solar for All efforts that paired federal grant funding with free installations. He said staff is analyzing options to expand access for customers who may not otherwise adopt battery or solar products.

The staff briefing concluded with commissioners requesting follow-up briefings: additional detail on thermal storage opportunities, more data about interconnection improvements for solar and batteries, and longer-term planning material to show how large capital investments play out over multi-decade horizons. Martin and other staff agreed to provide additional reporting to the commission.