Transmission-Constrained MUNI Retains Ascend to Develop Integrated Resource Plan Targeting 100% Clean Energy

Glendale Water & Power (GWP), a not-for-profit municipal utility with a peak load of 350 MW nine miles northeast of downtown Los Angeles, selected Ascend Analytics to develop an integrated resource plan (IRP). GWP aimed to efficiently establish an investment plan that would realize 100% clean energy for an electrically isolated community with material reliability concerns. Amid tight resource constraints and dependency on an unreliable transmission feed, GWP needed a plan that would allow the City to decarbonize their energy supply portfolio, maintain system reliability, and ensure the timely inclusion of local stakeholder input into the IRP process.

Maintaining Reliability and Decarbonizing Amid Tight Resource Constraints

The City Council of Glendale adopted a goal of 100% clean energy by 2035. GWP's current power supply contains approximately 65% zero-carbon energy, including 35% from renewable sources. GWP will serve more than 50% of load from renewable sources in 2025.  

Because of its location on the edge of a dense urban area buttressed by mountains, GWP faces severe transmission constraints that pose a supply resource contingency that’s proven vulnerable during peak demand periods. With limited land available for local resource development, GWP must maximize the effective use of existing transmission resources and build a system to insure reliability.  

Creating Multiple Resource Planning Scenarios, Engaging with Local Stakeholders

Leveraging its proprietary PowerSIMM software suite, the Ascend Analytics team performed a security constrained generation dispatch to determine least cost pathways to reliably serve load under a large variety of meteorological conditions. By searching over a broad set of potential resource options, Ascend developed multiple energy supply scenarios that provided clean pathways for GWP to meet their decarbonization goals while maintaining system reliability.  

GWP engaged Ascend team members to facilitate public meetings with local residents, as well as to participate in six meetings with a Strategic Technical Advisory Group (STAG).  Community members were polled at three town halls to understand their preferences regarding energy resources and clean energy timelines. This feedback was included in the subsequent development of resource planning models for GWP. Throughout the stakeholder process, Ascend worked with GWP to balance the diverse views on the priorities of Glendale’s electric plan.  

Developing a Road Map to 100% Clean Energy

Ascend Analytics modelled six scenarios for GWP and presented them to the STAG and City Council. Three scenarios were proposed by GWP and three were proposed by the STAG. These scenarios were based on a comprehensive, localized set of market fundamentals and forecasts that included energy demand, future costs, mix of energy resources (rooftop solar, wind, natural gas, etc.), transmission limits, and energy efficiency adoption – analyzed across various timetables.  Specifically, the Ascend team:

• Modelled electricity demand using forecasts from the CEC and Glendale-specific information to arrive at a final forecast that incorporated both total energy demand and peak demand (1-in-10-year events).
• Forecasted future resource costs, potential gains in energy efficiency, demand response expectation, and future customer growth.
• Applied PowerSIMM to model the Glendale power system to show how resources serve customer load and the carbon output (and reduction relative to long-term targets).
• Assessed system reliability with loss-of-load probability analysis with operating reserves to cover contingency events (N-1 and N-1-1).
• Provided planning scenarios that included feasibility assessments related to cost, resource type, and technical capacity, all within the context of renewable energy mandates, community interests, and reliability.

The results, summarized in Figure 1, detailed the total cost over 20 years and the carbon emission reductions by 2035 for the six scenarios. The chart groups scenarios by the timeline for eliminating carbon emissions. The first two scenarios meet the current California policy of serving retail load with clean energy by 2045. The next two scenarios achieve 100% clean energy by 2040 and 2042 respectively. The last two scenarios both meet the clean energy target by 2035.  

Ascend presented comparisons of the scenarios to the community and City Council in an unbiased format to allow the Council to select their preferred scenario. With all the necessary information to make an informed decision, the City Council approved the last scenario in Figure 1 to accomplish the clean energy goals by 2035 with a strong focus on local and distributed resources.

At the end of the intensive seven-month process, Ascend Analytics created alignment on an Integrated Resource Plan to serve as a road map for meeting total energy demand over the next 20 years, while accounting for peak demand (1-in-10-year events) and putting GWP on a path toward most efficiently realizing its 100% clean energy goal by 2035.  

Interested in Learning More?

The PowerSIMM™ energy analytics platform offers portfolio management, resource planning, reliability analysis, and valuation capabilities leveraging Ascend’s high-definition production cost model (HD-PCM) and Market Intelligence forecasts of future energy, emissions, and REC prices. Contact us to learn more.