Path 15 Upgrade Project uses teamwork to break transmission bottleneck
A historic partnership is moving steadily toward the cure of an 84-mile headache that has plagued the California electric transmission grid for nearly two decades, and that cure may save the state's electricity consumers millions in energy costs.
Western has teamed with the independent transmission company Trans-Elect, Inc., and investor-owned Pacific Gas and Electric Company to upgrade Path 15, as the transmission corridor is known. This critical section moves power between northern and southern California
More transfer capacity needed to prevent future blackouts
The problem with Path 15 is that it narrows from three to two 500-kV transmission lines between Los Banos and the Gates Substation near Coalinga, limiting much-needed transfer capacity. Factoring the effect of temperatures, load, generator shedding and Pacific Northwest power imports on available transfer capability, available capacity can range from about 3,700 MW to as little as 900 MW.
Studies done by the California Independent System Operator showed that congestion on Path 15 cost the state's electricity consumers $221.7 million in additional energy costs between Sept. 1, 1999 and Dec. 31, 2000. "And that bottleneck contributed to the northern California blackouts," added Sierra Nevada Regional Public Affairs and Energy Services Specialist David Christy.
The upgrade will add a third transmission line and modify substations at either end of the section to allow for the transfer of an additional 1,500 megawatts across the state.
Partnerships could reduce cost of upgrading U.S. grid
The California energy crisis highlighted the need to relieve the long- standing congestion caused by Path 15. In May 2001, Secretary of Energy Spencer Abraham directed Western to explore an upgrade and to determine whether non-Federal parties would be interested in helping finance and co-own the system additions. The result is a partnership in which Western is managing the $306 million project, Trans-Elect is funding the 500-kV line and PG&E is financing and doing the substation work.
The Path 15 Upgrade Project is one of the largest projects Western has undertaken since the California-Oregon Transmission Project was completed in 1992, and represents the first public-private partnership to undertake such a project. Western will own the line and retain a 10-percent share of its transmission capacity. For its investment in substation improvements, PG&E initially will receive approximately 18 percent of the new transmission capacity, depending on actual costs. Trans-Elect is providing the balance of the funding for the project and will receive approximately 72 percent ownership of the new transmission capacity. The additional capacity will be made available to all transmission users through the ISO.
Both the utility industry and the investment community are watching the project to see if it offers a model for other transmission improvements. So far, the reviews are favorable. In 2003, Project Finance International magazine awarded it the Infrastructure Deal of the Year for the Americas and Project Finance magazine named Path 15 its North American Power Infrastructure Deal of the Year.
Planning, design choices reduce project's environmental effects
On Dec. 30, 2002, Western, Trans-Elect and PG&E signed a Construction and Coordination Agreement, spelling out project terms and conditions in detail. Western selected contractors Maslonka & Associates the following May, and broke ground on the upgrade in September. The new line is scheduled to go online late this year.
Most of the planning for the upgrade was completed in the mid-'80s as part of the California-Oregon Transmission Project. Although the Path 15 upgrade was not built in the final COTP, Western was able to build on that effort.
The Path 15 Upgrade Project runs through the foothills of the San Joaquin Valley in the corridor west of Interstate 5. Much of the transmission line runs through farmland, sensitive wildlife habitat and historical and cultural resources. The Final Environmental Impact Review adopted by the California Public Utilities Commission determined that the proposed route west of the freeway was an environmentally superior option.
Western signed a plan to minimize adverse environmental effects and, with other agencies, an agreement for addressing the treatment of historical, cultural and Native American sites. Design measures taken to protect the area's unique features include rerouting an access road to avoid sensitive plant life. Engineers used steel poles in some areas because they have a smaller footprint than lattice towers and because they accommodate anti-perch devices to discourage raptors from landing on them.
Path 15 on schedule to ease state's energy woes
Careful planning has enabled project partners to keep construction on schedule while protecting the corridor's ecosystem. Through April 15, the contractor had completed access roads to all 343 tower sites; completed 244 lattice tower foundations (99 percent complete); completed 64 steel pole foundations (65 percent complete); erected 53 lattice towers (21 percent complete); and erected 31 steel poles (31percent complete). When the Path 15 partnership commissions the upgrade in late 2004, both public and private power customers will benefit from the more reliable transmission system. "The fact that Western is moving ahead with construction will benefit all of California's electricity consumers," said California Energy Commissioner John Geesman.
The upgrade will save Californians money—$100 million in energy costs during a normal year and more than $300 million during a dry year, the ISO estimated. Just as important for the state's long-term energy needs, "It will be an extremely valuable highway for moving renewable energy to both northern and southern California," Geesman stated.
California's experience with Path 15 shows that transmission constraints can affect the reliability and cost of power and present an obstacle to developing new resources. Correcting the problem is a complex and costly chore that technical expertise alone cannot complete. Western has welcomed the opportunity to join a partnership that may point the way toward a new solution to maintaining our nation's transmission system.