As part of a new model of electric transmission ownership and operation, TransWest Express LLC has submitted an application to the California Independent System Operator (ISO) under which the ISO would operate the TransWest Express Transmission Project as part of its long-distance, high-voltage transmission system network.
The California ISO is the largest of the 38 balancing authorities within the Western Interconnection and is responsible for matching generation with load and maintaining consistent electric frequency of the grid. The ISO manages the flow of electricity for approximately 80% of California and a small part of Nevada, delivering wholesale electricity to local utilities for distribution.
The TWE Project is a 732-mile high-voltage interregional transmission system with HVDC and HVAC segments that will connect to the existing grid in Wyoming and Utah as well as directly to the ISO Controlled Grid in southern Nevada. The TWE Project will deliver wind energy from Wyoming to California and other western renewable energy markets.
TransWest has been granted negotiated rate authority by the Federal Energy Regulatory Commission and has subscribed long-term firm point-to-point transmission service in the north-to-south direction on the TWE Project through an open solicitation process approved by FERC.
Under a proposed contractual arrangement, TransWest would become the ISO’s first Subscriber Participating Transmission Owner, or SPTO. TransWest would continue to derive revenues for long-term firm transmission service from its subscribers and for other transmission services under a separate wheeling charge. In the proposed SPTO model, the TWE Project will become part of the ISO network without increasing the ISO’s transmission access charge.
Joining a balancing authority is another step forward in integrating the TWE Project into the Western Interconnection’s bulk power system.
“It makes both technical and commercial sense for the operation of the TWE Project to be handled by the California ISO,” says Roxane Perruso, TransWest’s COO. “The SPTO model is an example of a simple solution addressing some of the complex challenges associated with transmission.”
