Through the first four months of 2026, coal-fired power generation has maintained a notable economic advantage over natural gas-fired generation across the Midcontinent Independent System Operator (MISO) territory, according to electricity, fuel, and wholesale market price data.
The key metric driving this assessment is the dark spread — the margin between the wholesale electricity price and the fuel cost required to produce that electricity from coal. When compared against the spark spread, which represents the analogous revenue-minus-fuel-cost calculation for natural gas generators, coal's dark spread has consistently outperformed in the MISO region during this period.
A positive and widening dark spread relative to the spark spread indicates that coal plants are capturing greater net revenue per megawatt-hour than their gas-fired counterparts, reinforcing the short-term economic case for continued coal dispatch. This dynamic is particularly relevant in MISO's central and southern zones, where a significant share of the legacy coal fleet remains operational.
The competitive positioning of coal in this market has broader implications for grid planning and resource adequacy assessments. Utility operators and independent power producers evaluating early retirement decisions for coal assets may find the current price environment an obstacle to accelerated decommissioning timelines. Conversely, renewable developers and storage investors will be watching whether this spread relationship persists or reverses as natural gas infrastructure and carbon policy frameworks evolve.
For MISO as a grid operator, the sustained economic viability of coal complicates long-term transmission and capacity planning, particularly as the region works to integrate growing volumes of wind and solar generation. Market participants will be closely monitoring how fuel price dynamics shift in the coming quarters and whether regulatory signals begin to reshape dispatch economics.
