New studies show that San Diego Gas & Electric’s Sunrise Powerlink transmission line project will cost up to $15 million a year less than other energy plans. Robert Sparks, lead engineer for the California Independent System Operator, presented the findings at a March 27 workshop attended by engineers, consultants, environmentalists, and SDG&E representatives. The project would supply power to San Diego for about $45 million a year, while alternative proposals studied by the grid operator range from $55 million to $60 million a year. Despite the estimated $10 million to $15 million in savings, environmentalists continue to question whether the 150-mile high-voltage line is needed. A variety of emerging renewable energy alternatives could be employed to generate new power in San Diego County, they say. Environmental groups have criticized the utility’s plan because it relies heavily on traditional electric power sources and discounts solar, geothermal, wind, and other renewable energy options. The construction of the power lines also is controversial because the proposed route goes through the Anza-Borrego Desert State Park. The grid operator will continue to study other alternatives to find the most viable plan, said Judy Sanders, CAISO lawyer. The current proposal for the Sunrise project would bring in geothermal and solar energy, but just how much is in dispute. CAISO’s study shows that about 1,600 MW of new geothermal energy from Imperial Valley could be tapped. “I’d say 800 MW would be more realistic,” countered David Hogan, conservation manager for the Center for Biological Diversity. The Sunrise project will mainly reduce reliance on local energy resources. “With the addition of the Sunrise Powerlink, you can reduce the local capacity requirements by 1,000 MW,” Sparks said. CAISO will complete the next phase of studies by the end of this month and present analysis for emerging alternatives to the project, along with more details on the existing proposal, on April 20.