New Electric Transmission Technologies for Renewable Integration Available to Purchase

California has established aggressive Renewables Portfolio Standard (RPS) goals to increase the fraction of electricity generated from renewable energy resources and to decrease greenhouse gas emissions. Legislation AB 32 requires 20% of California’s electricity to come from renewables by 2010. More recently, an executive order has set a goal of 33% by 2020. Most of this new renewable generation will require the electric grid for delivering its electricity to customers. Renewable generators will be integrated into the grid at both transmission and distribution levels, but most of this capacity is expected to connect to the transmission system in locations remote from load centers and existing transmission infrastructure. Consequently, new transmission extensions must be built. But permitting and constructing new transmission are taking considerably longer than they do for the power plants the new transmission will serve, creating a significant challenge for meeting the RPS goals. Once connected to the grid, some of this renewable generation will exhibit properties, such as intermittency, quite different from traditional generation and loads, which pose special challenges for providing timely grid delivery capacity, maintaining reliability, and avoiding economic inefficiencies. Finally, power flow constraints through existing transmission “gateways” into population centers must be relieved before the electricity from renewables can reach customers. Meeting these challenges will require new or expanded capabilities for the grid. At higher RPS levels, the conventional “build” solutions, namely new extension lines, expanding the capacity of existing transmission gateways to load centers, and building conventional power plants for support, will prove inadequate by themselves, either because they are not the most cost effective or can’t be permitted. New transmission technologies offer the prospect of providing a substantial portion of these new or expanded capabilities to supplement these build solutions. This paper provides a technology development survey for achieving an electric transmission infrastructure functionally capable of performing its role in meeting the Renewables Portfolio Standard goals. These new technologies were examined in the context of providing three new or expanded broad capabilities: (1) Provide physical access for each new power plant, (2) Reliably accommodate any unique renewable generator behaviors, and (3) Increase the grid’s power carrying capacity to handle the additional electric power flows. Many of these new capabilities will foster a more intelligent, robust and flexible transmission system as part of the Smart Grid. This intelligence also opens the prospects for an expanded role for distributed renewable generation to help meet the RPS goals and reduce some of the burden on transmission. Finally new physical capabilities must be added to turn the intelligence into actions.