Posted: June 19, 2026, 1:47 pm

Summer is Here

This weekend marks the official start of summer with the solstice occurring early Sunday morning. At the risk of being a downer, this also marks the point in the calendar where the days start getting shorter, well not really, but less sunlight.

The start of summer, and less sunlight, can be a problem for ISOs as solar becomes more of the generation mix. As we move later into the summer, and even into fall, less and less sunlight is left to power solar generation later in the afternoon when it might be needed. Looking to the Midwest and MISO, last September, Chicago saw 90 degrees on September 29 while Minneapolis saw 92 on September 16. 90 degree days in September are a real problem for grid operators as solar generation comes offline at about the time folks are getting home from work and turning on the AC (high). Doing a little reverse engineering using a calculator or fingers, counting forward and back gets you about the same sunlight on September 20 as March 20, and if you want to get really technical, you could throw in ambient air temps and air quality which are both better for production in March. The bottom line, a solar plant near Chicago is probably going to produce 30% less generation in September than June with the bulk of the decline in the afternoon and morning (less hours), but some loss coming throughout the day because of sun angle in the sky.

While this is sort of a new phenomenon in MISO given the rise of solar, CAISO and ERCOT have been dealing with this for years. In fact, in California, this action was coined the Duck Curve years ago. The Duck Curve is graphing out the ISO load after subtracting the solar generation from the load. The curve gets its name because of its shape shown in the image below, provided by Synetrics Energy.

This image shows that during the middle of the day, there is plenty of solar left to push the net load (load minus solar) down but ramps as load grows while solar generation wanes at the end of the day. While this can be challenging to grid operators with available generation, as we’ve seen in ERCOT the last couple years, it is more likely to show up in electricity prices as higher real time prices are required to get peaking generation to come online. As we’ve covered, over the last couple years we’ve started to see MISO call for conservative operations and capacity advisories during the late fall which was unthinkable five to ten years ago.

While the summer solstice got us thinking about solar generation, EIA’s June STEO included the reminder of what could be coming. Because of a weather forecast showing above average temps for the remainder of the summer, EIA is increasing their June-September cooling degree days by 3%, which in English means warmer temps and more electricity usage. What struck us was they predict solar generation to be up 19% year over year which will offset the 2% decline in coal burn. As seen in the chart below, the 19% sounds like a lot, but in the bigger picture it’s not that much. That said, when we get into those hot September days, if solar is being counted on to replace coal, well we’ve seen this movie before and it might get interesting.

Natural Gas Market Commentary

Speaking of Natural Gas, the EIA chart above is proof enough that natural gas is still king in the US and drives the majority of electric pricing. Diving down into the report, EIA is lowering their rest of year forecast for Henry Hub pricing from January. The revision is being driven by ample storage levels and increased production. Looking at the chart on the right, EIA is increasing their production forecast by 3.3% in 2026, or 3.9 Bcf/d and by 2.5%, or 4.6 Bcf/d in 2027. Again, as we’ve noted, right now the US is maxed out on export capacity so any increase in production stays home for domestic consumption….more supply and equal demand means lower prices.

Happy Father’s Day

This weekend is Father’s Day. We want to recognize all the fathers out there and hope you enjoy the day. Doing a little research, we found that President Lydon Johnson proclaimed the third Sunday in June be recognized as Father’s Day in 1966. Also, according to Hallmark, Father’s Day is number four in holiday card sales, well behind Christmas, Valentine, and Mother’s Day. We also uncovered some interesting facts about the day celebrated in other cultures which got us thinking about our own anecdotal research.

According to us, and our in depth research, we found that father’s around the world want the same. The only cultural difference is the sport on the screen in the picture below. Again, Happy Father’s Day