TX SB2021

Defines "distributed energy resource" as electricity sources connected at less than 60 kilovolts, including energy storage, distributed generation, natural gas generation, and electric vehicles that provide power to the distribution system

Defines "aggregated distributed energy resource" as a group of distributed energy resources operated together as a single unit, with each individual resource producing no more than 1.5 megawatts (adjustable by commission rule)

Requires the Public Utility Commission to establish rules for ERCOT covering dispatchability and reliability requirements, customer protections, interconnection guidelines, and a methodology for allocating and recovering transmission and distribution utility costs for interconnections

Allows distributed energy resource owners who are part of aggregated resources to sell surplus electricity only to their serving retail electric provider at a mutually agreed value, potentially based on market clearing prices

Protects distribution service providers from being obligated to interconnect resources of 10 megawatts or greater, and shields interconnecting utilities from liability for reliability violations caused by distributed energy resources that violate interconnection agreements