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The High Voltage Debate: Why the RTRP can’t afford more delays

As Riverside grapples with the future of its electric grid, the Riverside Transmission Reliability Project faces critical decisions that will impact the city’s energy security for decades.

The Riverside Transmission Reliability Project (RTRP) is designed to provide the city of Riverside a second point of connection to the statewide electric grid, which delivers electricity generated from a variety of sources throughout the Western United States and even Western Canada. In California, the grid is operated by a state entity called the Independent System Operator. Riverside has been connected to the grid for decades by several (currently six) 69,000 Volt (69 kV) transmission lines, all originating at Southern California Edison’s Vista Substation. The Vista Substation is located in Colton on the top of the bluff you pass over if you are going north on the I-215 Freeway toward San Bernardino.

There are two problems with this arrangement. First, the capacity of Vista Substation and the six 69kV transmission lines is significantly less than the peak demand Riverside Public Utilities sees during the summer. More importantly, if anything happens to Vista Substation or the connecting transmission lines, which follow largely the same path until they diverge within our city, Riverside could lose its connection to the statewide grid. leaving us with significantly less electricity capacity than our city needs which would result in blackouts. This has happened in the past and will almost inevitably happen without a second connection to the grid. Our greatest risk for prolonged loss of connection is damage to Vista Substation, which sits almost on top of the San Jacinto Fault – a large active fault capable of producing a major earthquake.

The RTRP is designed to connect Riverside to a different power source fed from the Mira Loma Substation in Ontario. The new connection would be at a higher voltage, 230kV. This larger line would be capable of delivering all the electrical demand of the city even with future growth. Riverside would be much less likely to experience a citywide blackout with both connection points in service.

After a five-year-long process with many hearings, filings, and arguments, The California Public Utilities Commission approved the RTRP in March 2020.

Transmission Line Route and Design

The RTRP line would begin in the City of Eastvale and traverse the cities of Jurupa Valley, Norco, and Riverside to a new substation to be built near Van Buren Boulevard, where it crosses the Santa Ana River. Most of the line would be built using lattice steel towers over 100 feet tall. Portions of the line in Jurupa Valley would be built underground. The route crosses commercial and residential properties, a golf course, and open space along the Santa Ana River in Norco and Riverside. The new substation would be in a commercial area adjacent to the city’s sewer treatment plant. As proposed, Southern California Edison will build the RTRP, and the over $500 Million cost will be spread across all Edison customers.

The Issue

There is renewed pressure to underground the portion of the line through Norco and Riverside to reduce visual impact and the perceived danger of an overhead line causing fires. However, underground is much more expensive than overhead construction, and who would pay the increased cost is a concern.

The Riverside City Council delayed moving the project forward while additional undergrounding was explored. A group of residents have worked with local, state, and federal officials to identify potential funding sources, particularly at the federal level. They believe they have identified sources of money, but it cannot be secured until next fiscal year and must go through a process to be awarded.

There is no doubt that undergrounding the line would reduce the visual impacts of tall steel towers. Realistically, undergrounding the line would have little effect on reducing fire danger. The lattice steel towers are very strong, and the wires are placed a minimum of 40 feet from the ground and much farther apart than on lower-voltage power lines. This type of electric line rarely fails or comes into contact with trees, the primary way lower voltage overhead lines built on wood poles start fires. Lower voltage wires may be only 20 feet from the ground, and the wood poles they are strung on can be damaged in various ways, like being hit by a vehicle or burning in a fire. Because the wires carrying the electricity are so far apart on the new transmission line, it is almost impossible for flying debris like a palm frond or mylar balloons to cause a spark between the wires, as can happen with lower voltage lines where the wires are much closer together.

The bigger problem is that the project's environmental review considered undergrounding more or even all of the line and concluded that undergrounding the line adjacent to the Santa Ana River in Norco and Riverside would have a greater overall negative impact than overhead construction. This primarily impacts plant and animal species because undergrounding requires a trench, while overhead disturbs a smaller area at each tower location. Both underground and overhead construction will require an unpaved access road, which would be similar for either construction method. Undergrounding also has a greater potential impact on archaeological and paleontological resources with a trench rather than overhead towers. It is known that Native American people lived along the river, and there are also sites with significant fossils along the river.

Changing from overhead to underground construction would require redoing the environmental review and securing a revised Public Utilities Commission approval, which would delay the project by a minimum of two years and possibly four to five years like the initial approval. There is no evidence that a new environmental review would reach a conclusion different than the existing review, which rejected undergrounding in Norco and Riverside, so the permitting agency could reject additional undergrounding on an environmental basis.

So Now What?

The environmental review of the RTRP considered multiple routes and not building the project at all. The environmental report and the California Public Commission concluded that the approved route and design had the least negative impact and that the project was necessary.

There is no question that building a major electric transmission line will have significant impacts along its route. No one can blame people living and working near the route for wanting it to be somewhere else, or at least not as visible. Everyone has their view on the project and how it should be built. It is time for Riverside to decide whether further delay and a possible change from overhead to underground construction are worth the risk and the ever-increasing construction cost. I urge everyone to let the Mayor and Council know your view and urge them to make a definitive decision as expeditiously as possible. We have waited too long already.