Brattle Experts Assess Electrification Impacts on Pepco’s Washington, DC Distribution System
Prepared for Pepco
Brattle experts have authored an assessment of the distribution grid impacts of electrification and the related value of grid flexibility in the District of Columbia. The study was filed with the DC Public Service Commission in response to Order 22313, which directed Pepco to develop a granular assessment on the distribution system costs of full electrification in the District.
The study contains granular modeling of the electric demand impacts of achieving the District’s electrification goals, identifies related constraints on Pepco’s electric distribution system, and estimates the cost of potential grid upgrades needed by 2040. Further, the study illustrates the ability of a portfolio of distributed energy resources, energy efficiency, and demand flexibility technologies – collectively referred to as “grid flexibility” – to mitigate the need for grid upgrades.
The findings of the report include:
- The Pepco DC system currently has significant capacity headroom for load growth, especially in the winter. Most parts of the system can support electrification loads through 2040 without additional upgrades. However, the areas requiring upgrades due to electrification will increase the total investment need relative to recent levels.
- Without grid flexibility, meeting the District’s electrification goals could more than double Pepco’s capacity expansion expenditures by 2040. Pepco’s capacity expansion needs from 2025 to 2040 are estimated to cost $665 million in a scenario with no additional electrification and $1,594 in a scenario with full electrification and no grid flexibility.
- Grid flexibility technologies could be a feasible solution to reduce capacity expansion expenditures. A portfolio of grid flexibility technologies – rooftop solar, batteries, weatherization, cold climate heat pumps, managed electric vehicle (EV) charging, and smart thermostats – could reduce the required capital expenditures (capex) by $58 to $868 million (4% to 54%).
- There is significant value in the targeted deployment of grid flexibility in areas where grid capacity expansion would be particularly expensive. The grid capacity expansion solutions to mitigate overloads have a wide range of costs. Grid flexibility is shown to be particularly valuable to deploy in locations where the most expensive capacity expansion projects may be needed, and where overload conditions are limited in terms of duration, magnitude, and rate of growth.
- Scale is essential to achieve grid flexibility value. The distribution value of grid flexibility is highly dependent on deployment reaching significant scale in the locations where it is needed most; moderate levels of deployment are unlikely to produce meaningful distribution benefits.
- Cold climate heat pumps are a particularly valuable grid flexibility technology. The efficiency-related savings of cold-climate heat pumps (relative to heat pumps with auxiliary resistive heating) tend to be coincident with the winter peak and can be a major contributor to grid flexibility portfolios that defer the need for grid upgrades.
- Batteries provide unique value to the grid flexibility portfolio. Batteries are flexible from both an operational and siting perspective, with the option to take advantage of efficiencies by siting them at the customer’s premise or to attach them to the distribution system where needed most. Batteries can act as the “glue” that enables the rest of the grid flexibility portfolio to provide benefits.
The report, “An Assessment of Electrification Impacts on the Pepco DC Distribution System,” was prepared by Principals Ryan Hledik, Sanem Sergici, and Michael Hagerty; Managing Energy Associate Akhilesh Ramakrishnan; Energy Research Associate Adam Bigelow; Senior Energy Analyst Oliver Grocott; and Energy Analyst Tina Zhang. The full report and technical appendix are available below.
