Recently Salt River Project (SRP), a not-for-profit utility that provides water and energy to more than 2 million people in central Arizona, published its first-ever Integrated System Plan (ISP). The ISP was an industry-leading effort to bring together planning groups from across the organization to perform comprehensive electric system planning from now through 2035.
E3 supported SRP through all phases of the ISP, from initial planning in 2020 to completion in 2024. E3 helped SRP identify the objectives for the process and design an analytical framework and stakeholder engagement plan that were used in carrying out the ISP. E3’s analytical support included resource cost forecasting, long-term capacity expansion modeling, financial modeling, and economywide greenhouse gas reduction analysis. In addition, E3 helped SRP translate analysis results into key findings, future system strategies, and action plans and helped SRP communicate these outcomes to stakeholders and SRP’s Board and Council.
This was the first time that SRP performed system-wide modeling through 2035 to understand the affordability, reliability, and sustainability implications of different planning pathways. SRP performed analysis across more than 40 planning cases to understand investment needs, customer participation, and system operations across a diverse range of futures. E3 performed capacity expansion modeling in PLEXOS to develop least-cost resource plans across all planning cases, which fed into transmission planning, financial modeling, and avoided cost analysis. SRP also engaged customers and other stakeholders across more than 30 meetings to ensure that the ISP considered a wide range of perspectives.
Based on key findings from SRP and E3’s analysis and input from stakeholders, SRP developed seven System Strategies to guide planning decisions through 2035, as well as ten near-term ISP Actions that further the System Strategies. Together, these outcomes reflect a significant increase in renewables, storage, and customer programs to drive carbon emissions reductions, as well as investment in firm generation, delivery infrastructure, and other solutions to maintain reliable and affordable power. The SRP District Board of Directors approved the System Strategies last fall, and E3 played an active role in communicating the ISP analysis and outcomes, presenting at stakeholder meetings and SRP’s Board and Council work study sessions.
To illustrate how SRP’s system could evolve through 2035 through implementation of the strategies, SRP also developed a Balanced System Plan (BSP) with E3’s support. The BSP underscores the magnitude of change across all parts of the system between now and 2035, adding more than 11,000 MW of new resources, retiring 1,300 MW of coal capacity, adding 190 miles of transmission, adding 65 new distribution bays, reaching 3,800 GWh of energy efficiency and 300 MW of demand response, and helping facilitate customer adoption of 1,500 MW of rooftop solar and more than half a million electric vehicles. As SRP works to carry out the System Strategies and realize these monumental shifts in the energy system, the ISP will play a key role in guiding SRP’s planning efforts.
