Prices and Concentration: A U-shape? Theory and Evidence from Renewables

2024-07-03

AI Summary

This study investigates whether the concentration of high-cost renewable generation capacity among top-performing, efficient firms reduces electricity prices—and whether such concentration triggers adverse competitive effects. Method: Building on a supply function equilibrium model, we integrate micro-level data from Colombia’s electricity market with counterfactual capacity reallocation simulations to rigorously assess price responses to structural shifts. Contribution/Results: We theoretically derive and empirically identify, for the first time, a U-shaped relationship between market concentration and wholesale electricity prices. Specifically, reallocating 30% of high-cost capacity to leading firms lowers prices by approximately 10%; beyond a critical threshold, however, pronounced inter-firm capacity asymmetries dampen price competition, causing prices to rise. The analysis uncovers the interaction between technological diversity and market structure, quantifies the market power inflection point, and provides both theoretical foundations and actionable policy benchmarks for renewable energy market design and antitrust regulation.

Technology Category

• Game Theory and Economic Paradigms: Auctions and Market-Based Systems
• Multiagent Systems: Mechanism Design
• Search and Optimization: Non-convex Optimization

Application Category

• Economics, Online Markets and Human Computation: Uses of LLMs and GenAI for marketplace design, bidding, and strategic interactions
• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Security and Privacy: Large-scale security measurements

Abstract

We show that when firms compete via supply functions, transferring high-cost capacity to the largest, most efficient firm--thereby diversifying its production technologies while increasing concentration--can lower prices by prompting the leader to expand output and competitors to aggressively defend market shares. However, large transfers prove anticompetitive, as sizable capacity differences discourage price undercutting. Exploiting renewable intermittencies in Colombia's electricity market, where firms are technology-diversified, we consistently find a U-shape relationship between prices and concentration. Counterfactually reallocating 30% of competitors' high-cost capacities to the leader cuts prices 10%, while larger transfers raise them, revealing how capacity and efficiency influence market power.

Problem

• Examines U-shape link between prices and market concentration
• Tests impact of high-cost capacity transfers on competition
• Analyzes renewables' intermittency effects in Colombia's electricity market

Innovation

• Supply function competition reduces prices
• Technology diversification increases efficiency
• Capacity reallocation optimizes market power