Coal-fired power generation held a consistent profitability advantage over natural gas generation across the MISO region in the first four months of 2026, according to new data from the U.S. Energy Information Administration. Measured by dark and spark spreads — standard indicators of how much revenue generators earn above their fuel costs — coal outpaced natural gas every month through April.
Coal holds profitability edge over natural gas in MISO through April 2026
EIA data show that coal’s dark spread averaged $28/MWh during the first four months of 2026 in the MISO region. That figure is 39% above the same period in 2025. The spark spread for natural gas, over that same stretch, averaged $9/MWh — a 15% year-over-year increase, but still well below coal’s margin.
Both spreads measure the difference between wholesale electricity prices and the cost of fuel used to generate that electricity. A higher spread means a generator earns more above its fuel costs. Coal has held a clear and growing advantage by that measure.
The pattern is not new. According to EIA, the dark spread in MISO began consistently exceeding the spark spread in late 2024. Early 2026 brought a change in scale rather than direction — the gap widened sharply during a January winter storm.
Diverging fuel price trends explain the widening gap between coal and gas economics
Coal’s profitability advantage has roots in 2024 and 2025, when electricity and fuel prices moved in very different directions depending on the fuel type.
Average electricity prices in MISO rose 44% from 2024 to 2025. For coal generators, that was largely a windfall: coal prices increased only 3% over the same period. The dark spread grew from $11/MWh in 2024 to $23/MWh in 2025 — a 111% year-over-year increase.
Natural gas generators faced a harder road. Gas prices rose 63% between 2024 and 2025, nearly canceling out the benefit of higher electricity prices. The spark spread grew by just $2/MWh, moving from $12/MWh to $14/MWh — 18% growth, against coal’s 111%.
That asymmetry set the stage for 2026. Coal entered the year with a stronger profitability baseline; natural gas entered it far more exposed to any further fuel cost volatility.
Winter Storm Fern pushed the spread difference to $530/MWh for six consecutive days in January
Winter Storm Fern, which struck in late January 2026, turned a structural advantage into a dramatic one.
Daily average power prices in MISO exceeded $260/MWh from January 26 to January 28. Electricity demand during those six days actually ran 11% below pre-storm weekday levels — meaning the price spikes were not driven by surging consumption. They reflected surging natural gas prices instead.
Heating demand during the storm sent natural gas spot prices sharply higher, moving from $25/MWh on January 20 to $549/MWh by January 27 — a more than twentyfold increase in one week. Coal prices barely moved. At the storm’s peak, the difference between dark and spark spreads reached $530/MWh, capturing just how exposed gas generators were to that fuel cost spike.
Structural market differences between coal and natural gas underpin price stability
Why coal prices held steady during Winter Storm Fern comes down to how each fuel physically reaches a power plant.
Most natural gas-fired generators connect directly to pipeline infrastructure, which means spot-market purchases can be delivered almost immediately. Prices respond in near real time to demand changes — including sudden surges from heating loads during extreme cold. Coal works on an entirely different timeline. Spot coal purchases require roughly one month of lead time because the fuel must be physically transported to the plant after purchase. When heating demand spiked during Fern, coal prices had no mechanism to follow.
This delivery lag has historically insulated coal from short-term demand swings during extreme weather. EIA also noted that MISO’s trends differ from those observed in the PJM market, which was the subject of a separate dark and spark spread analysis.
Key takeaways
The core finding is straightforward. Coal-fired generation in MISO has been more profitable than natural gas generation by a widening margin since late 2024 — a gap shaped by two forces: coal fuel costs rising far more slowly than electricity prices, and natural gas fuel costs rising fast enough to erode most of the electricity price gains for gas generators.
Winter Storm Fern amplified that gap to an extreme degree, with a $530/MWh spread difference driven by a natural gas price spike that coal’s delivery structure made it immune to. Through April 2026, coal’s dark spread remained 39% above its year-earlier level, while the spark spread lagged at just 15% growth.
Carlos is an engineer with strong expertise in technical and industrial topics. He previously worked at international companies such as Siemens and speaks Spanish, German, English, and Italian.
