THE RELATIONSHIP BETWEEN ELECTRIC POWER SYSTEM REGULATORY STRUCTURE AND RENEWABLE ENERGY GROWTH IN THE UNITED STATES FROM 2010 TO 2020

Abstract

The regulatory structure of the electric power system in the U.S. follows two basic models. Historically, vertically integrated public utilities, operating as monopolies, have controlled electricity generation, transmission, and distribution. This regulated structure has been retained by 23 states. The other 27 states have restructured, or deregulated, their electricity market such that Regional Transmission Organizations balance system load and operate bid-based wholesale electricity markets. This restructuring, intended to make price competition central to transmission system access, has opened the market to non-utility generators. The aim of the present study was to determine which of these two systems has been more conducive to renewable energy growth within the last decade. Recent cost declines have made wind and solar power costcompetitive, suggesting that a deregulated market structure may facilitate their growth. Annual wind and solar photovoltaic capacity additions, expressed as a percentage of total capacity addition, were analyzed. Deregulated states displayed greater wind capacity growth between 2010 and 2020 than regulated states. Much of this dominance was explained by a more favorable wind resource quality; however, deregulation had significant additional predictive power. Regulated states, in contrast, displayed significantly greater solar capacity growth, with steep acceleration even prior to solar power becoming broadly cost-competitive. A more favorable solar resource quality explained much of this difference, especially in later years when CapEx had declined. State Renewable Portfolio Standards (RPS) predicted solar capacity growth only among deregulated states, which average more ambitious RPS targets than regulated states. Regulatory status per se accounted for a small additional fraction of between-state variance in solar capacity growth. In summary, deregulation appears to have facilitated wind capacity deployment but may have slowed solar capacity growth. A regulated system may have been more conducive to solar capacity growth early on, when this technology was only marginally cost-competitive.