Optimal transmission expansion modestly reduces decarbonization costs of U.S. electricity

2024-02-22

AI Summary

This study quantifies the cost impact of interregional transmission expansion on a zero-carbon U.S. power system in 2050 and characterizes its substitutability with other flexibility resources—namely, energy storage, renewable siting, and nuclear generation. Using an open-source, high-resolution capacity-expansion model, we jointly optimize transmission reinforcement, generation portfolio, storage deployment, and hourly operations across all three U.S. interconnections. Results show that optimal interregional transmission expansion exceeds current capacity by over threefold but reduces total system costs by only 7%. In contrast, enhancing intra-regional coordination among generation, transmission, load, and storage—and maximizing utilization of existing transmission—substantially displaces the need for large-scale new interregional lines. The key contribution is demonstrating that a “local-generation-plus-system-coordination” pathway is more cost-effective than reliance on long-distance, high-capacity transmission, thereby establishing a lower-cost, infrastructure-light paradigm for clean power system transformation.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Game Theory and Economic Paradigms: Coordination and Collaboration
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization

Application Category

• Economics, Online Markets and Human Computation: Cost models of using LLMs in production systems
• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

Abstract

Solar and wind power are cost-competitive with fossil fuels, yet their intermittent nature presents challenges. Significant temporal and geographic differences in land, wind, and solar resources suggest that long-distance transmission could be particularly beneficial. Using a detailed, open-source model, we analyze optimal transmission expansion jointly with storage, generation, and hourly operations across the three primary interconnects in the United States. Transmission expansion offers far more benefits in a high-renewable system than in a system with mostly conventional generation. Yet while an optimal nationwide plan would have more than triple current interregional transmission, transmission decreases the cost of a 100% clean system by only 7% compared to a plan that relies solely on current transmission. Expanding capacity only within existing interconnects can achieve most of these savings. Adjustments to energy storage and generation mix can leverage the current interregional transmission infrastructure to build a clean power system at a reasonable cost.

Problem

• Evaluating how optimal transmission expansion reduces decarbonization costs
• Assessing transmission's role versus storage and renewable siting alternatives
• Determining cost-effective grid expansion strategies for zero-emissions systems

Innovation

• Tripling interregional transmission capacity nationwide
• Using reconductoring to quadruple line capacity cheaply
• Substituting transmission with storage and renewable siting