Determinants of the wholesale prices of energy and ancillary services in the U.S. Midcontinent electricity market

Abstract

This paper examines wholesale price behavior of energy and ancillary services (AS) in the day-ahead market (DAM) and real-time market (RTM) of the Midcontinent Independent System Operator (MISO), the second largest regional transmission organization in the U.S. Using hourly data for the period of 12/19/2013 to 12/30/2017, it estimates a system of 16 electricity price regressions that recognizes the interdependence of MISO’s electricity products. Its key findings are: (1) MISO’s regional DAM energy prices increase with the day-ahead forecasts of natural gas price and MISO’s regional loads, PJM’s DAM energy price at its MISO interface, and MISO’s DAM AS requirements; (2) MISO’s regional DAM energy prices decline with DAM schedules for nuclear and wind generation; (3) MISO’s regional RTM energy prices increase with, but diverge from, MISO’s regional DAM energy prices; (4) MISO’s system-average DAM AS prices increase with MISO’s system-average DAM energy price and procured amounts of AS; and (5) MISO’s system-average RTM AS prices increase with MISO’s system-average RTM energy price and system-average DAM AS prices. These findings imply that MISO can reduce its DAM and RTM prices for energy and AS by accelerating wind generation development, expanding demand-side-management, and easing inter-regional transmission congestion.