Non-Wires Alternatives to Building a New Substation in Washington, D.C. – Key Takeaways for Other Jurisdictions


Washington D.C. is experiencing rapid development of new residential and office buildings in and around the Mt. Vernon Triangle area. In response, the local utility has proposed building a new substation to serve the expected load growth at a cost of approximately $150 million. The utility reviewed and incorporated some energy efficiency and other distributed energy resources (DER) in its load forecast, but concluded that such non-wires solutions (NWAs) do not provide enough capacity to resolve the expected distribution constraints. However, Synapse Energy Economics’ analysis revealed that the utility’s plan did not adequately account for the potential impacts of cost-effective targeted DER solutions or future building codes.

Synapse conducted a comprehensive assessment of the utility’s load forecast and the feasibility of NWAs. We quantified cost-effective NWAs sufficient for deferring the need for the substation. This presentation highlights the key issues, assumptions, methodologies, and results from our analysis. Further, we present how our findings can be applied to other regions facing similar situations. Specifically, this presentation covers: (a) peak load forecasting methodologies; (b) peak load assumptions for existing buildings and new construction; (c) solar PV projections; and (d) achievable energy efficiency and demand response potential for the Mt. Vernon area. Synapse used building load data, existing end-use level potential studies, and program performance from leading programs to estimate energy efficiency and demand response potential. The presenter will also highlight studies and leading programs Synapse referenced to develop key assumptions on energy savings, costs, and participation rates.