June split cleanly down the middle across much of the country, and that divide anchors our latest Monthly Renewables Report, The Two Halves of June, now available as part of our Subscription Professional Plan. Warm early-month temperatures gave way to a cool back half from CAISO through the Midwest, with the weather flipping around the middle of the month before heat returned right at the very end. Load told different stories by region. CAISO, ERCOT, and SPP all came in above last June, while MISO and PJM landed below a year ago even with the early warmth. The bigger story sits with the renewable fleet, which kept growing fast enough to reshape each market. 

In CAISO, solar oversupply reached new extremes. Output peaked at 24.8 GW, and nearly half of all June solar generation showed up while real-time prices at SP15 were negative. That share eased from a remarkable 85% in May but still ran well above either of the past two Junes. Curtailments totaled 541 GWh, more than double June 2025, and the gap to last year keeps widening. Batteries continue to scale, with average peak evening dispatch finally topping 10 GW, yet storage still cannot keep pace with how quickly solar is climbing. Figure 1.4 captures the dynamic, with the 2026 panel showing far more negative pricing and heavier curtailment than a year earlier, driven by a heavy clustering of negative hourly net load values on the left of the figure compared to June of 2026.

Figure 1 | Previous Month CAISO System Solar vs. Net Load (Color Shows LMP, Point Size Shows Solar Curtailment)

ERCOT, meanwhile, leaned on wind. Generation reached a three-year June high of 28.7 GW and averaged 15.6 GW, pushing wind's market share to 24% and driving net load to some of its lowest levels late in the month. All that wind sent the West Hub real-time price to its lowest average monthly June mark in three years even as the other hubs hit three-year highs. As Figure 2.4 shows, the setup is already reversing in early July as wind output falls back toward the teens and heat builds, sending net load sharply higher.

Figure 2 | ERCOT Net Load

Those renewable gains showed up in prices well beyond the two lead markets, with real-time LMPs and implied heat rates falling year over year in SPP, MISO, and PJM as clean supply outpaced modest load growth. The full report breaks it all down region by region, covering solar, wind, behind-the-meter solar, batteries, and hydro alongside the weather, load, and net-load stories that tied June together.

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