Market power monitoring and mitigation in the US wholesale power markets

Under current statutory requirements, the Federal Energy Regulatory Commission (FERC) must ensure that prices in US wholesale power markets are ‘just and reasonable’. This has been interpreted by the agency and the courts as requiring the monitoring and mitigation of undue market power. This paper focuses on generation market power. Prior to electricity sector restructuring, wholesale bilateral power trading took place among vertically integrated monopoly utilities trading at the margin or between small independent producers and the utilities. Under those conditions, the authorization of trading at market prices, called ‘market-based rates’, required only that the generation supplier pass a simple market share screen for market power. As restructuring unfolded, and market conditions changed, there has been a steady evolution in FERC's market power mitigation rules, encompassing (a) changes in the market power assessment required for granting market-based rates and related methods for merger approval, and (b) development and refinement of new techniques for screening and mitigating offers into the organized day-ahead and real-time markets operated by Independent System Operators (ISOs) and Regional Transmission Organizations (RTOs). This paper reviews these changes to date, as FERC continues to clarify its approved rules and procedures. It also examines recent methods for quantitative market power analysis that could augment current procedures or supplant them, as found appropriate.