SEAS Events

Title: Economic and Climate Benefits of EV-system Integration Technologies

Chair: Dr. Parth Vaishnav

Abstract:

Road transportation accounts for 20% of all anthropogenic greenhouse gas (GHG) emissions globally. Electrification coupled with power sector decarbonization has become the center of road transportation decarbonization plans for many major economies. Yet, the convergence of electrification and renewable supply can introduce a systems-integration challenge. Wind and solar power generation can be variable and largely non-dispatchable, while electric vehicles (EV) add substantial load, straining the transmission and distribution network and contributing to demand-supply imbalance. We quantify the potential for EVs to charge and discharge strategically to optimize electricity costs and GHG emissions for households and for the bulk power system, to make it easier to decarbonize the residential and power sectors.

This dissertation advances the realistic representation of the electrified transportation sector and the power sector and their interactions at multiple model scales, assessing both financial and environmental impacts. The overarching goal is to identify opportunities that can lower barriers to decarbonization and generate actionable insights for key stakeholders in transport electrification and grid decarbonization. The dissertation is composed of three studies.

The first two of these focus on households and quantify lifetime costs and GHG impacts of EV-home integration across the contiguous US. The first study assesses charging costs, emissions, and battery degradation for individual EVs, incorporating local driving patterns, climate effects on EV efficiency, regional grid mixes, and household electricity profiles, while accounting for future grid decarbonization. Results show that optimizing charging and using EV batteries to optimally shift electricity purchases for other household loads, a strategy referred to as V2H, substantially reduce costs and emissions, in some regions fully offsetting EV charging costs or associated emissions. While simulated battery degradation impacts remain mild, transparency about battery degradation from driving and other potential EV applications, including V2H, is needed for realistic assessments of the full costs and benefits. Results also highlight the value for utilities, automakers and dealers, collaboratively providing customers with user-friendly tools to estimate controlled charging and V2H benefits.

While the first study uses modeled electricity prices and excludes distributed generation, the second study builds on the first by adopting a modeling strategy that bases EV charging decisions on residential solar photovoltaics (PV), real-world utility rates, and different, evolving PV feed-in tariffs. Controlled charging and V2H increase solar self-consumption, lower charging costs, and buffer households against solar tariff changes. While both controlled charging and V2H reduce emissions, the magnitude is smaller than in the first study, as most utility rates encourage charging overnight when generation is emissions intensive. This demonstrates that EV flexibility strengthens economic resilience of residential solar prosumers under solar tariff policy uncertainty.

The third study estimates the consequential power system emission effects of EV charging considering how EV charging strategies influence long-term renewable capacity expansion in the PJM Interconnection, the largest grid operator in the U.S., serving 65 million customers. Results show that while uncontrolled charging induces little additional renewable build-out, controlled charging and vehicle-to-grid (V2G) materially increase cost-effective wind and solar deployment and reduce system-wide emissions enough to result in net negative EV consequential emissions.

Across these studies, the dissertation provides a holistic techno-economic assessment of EV-system integration. It shows that uncontrolled charging offers limited emissions benefits and can strain the grid, whereas controlled charging, V2H, and V2G deliver substantial emissions reductions, bolster renewable integration, and reduce system costs—offering a clearer path toward a flexible and deeply decarbonized energy system.