​Real-time four-hour top-bottom (TB4) spreads in PJM averaged $473/MW-day in June, down 9% year over year. Day-ahead TB4 spreads went the other way, rising to $345/MW-day, up 24%. Peak demand fell 7% year over year, and the maximum real-time price fell 61%.

However, regulation spiked over June 10 and 11, clearing daily averages above $1,000/MW-day, on top of a baseline already raised by PJM's October 2025 market redesign.

PJM’s intraday shape flattened. Midday rose slightly, with hours 11 to 15 averaging $66/MWh against $59/MWh a year earlier. The evening peak eased in the other direction: HE19 average fell to $121/MWh from $174/MWh.

Key takeaways

• Real-time TB4 spreads averaged $473/MW-day, down 9% year over year from $517/MW-day. Day-ahead TB4 spreads rose across PJM to $345/MW-day, up 24% from $279/MW-day.
• Peak system demand fell 7% year over year, from 161 GW in June 2025 to 150 GW in June 2026. The evening peak hour eased to $121/MWh.
• Real-time regulation spiked to a daily average of $1,185/MW-day on June 11, more than three times June 2025's highest single day. Reserves stayed muted over the same window.
• Coal generation fell 15% year over year to 16 GW, while solar climbed 25% to 4.8 GW and wind rose 23% to 3 GW.
• Spreads stayed concentrated in the mid-Atlantic. Baltimore (BGE) led real-time at $1,026/MW-day, followed by Washington DC (PEPCO) and Virginia (DOM).

Real-time spreads eased 9% while day-ahead spreads widened

Real-time TB4 spreads averaged $473/MW-day in June, down 9% from $517 a year earlier.

Day-ahead spreads moved the opposite way. Four-hour day-ahead spreads rose to $345/MW-day, up 24% from $279 (day-ahead is reconstructed rather than direct; see the data note).

The three mid-Atlantic zones led PJM by a wide margin. Baltimore (BGE) topped the real-time TB4 spread leaderboard at $1,026/MW-day, followed by Washington DC (PEPCO) at $939/MW-day and Virginia (DOM) at $859/MW-day.

The rest of the footprint sat far lower. Allegheny (APS) averaged $516/MW-day and Dayton (DAY) $423/MW-day, while Pennsylvania (PPL), Philadelphia (PECO), and central New Jersey (JCPL) clustered near $290 to $330/MW-day.

Persistent transmission constraints between eastern load centers and western generation widen price separation when the system tightens.

Coal retired, solar rose, and the daily floor firmed in PJM

The generation mix was quite varied compared to June 2025, even as PJM faces a capacity shortage. Coal generation fell 15% year over year to 16 GW average, while solar climbed 25% to 4.8 GW and wind rose 23% to 3 GW.

Gas remained the dominant fuel at an average of 45 GW, down 3% year over year. PJM storage discharged on the evening ramp, cresting near 163 MW at 7 PM.

Two heat events drove the month's volatility across PJM

Two heat events supplied the volatility in an otherwise quiet month. The first was a mid-June East Coast heatwave during June 10 and 11. Real-time prices peaked at $719/MWh on June 11 at 5 PM, far above the $31/MWh median hour, with demand at 145 GW at 5 PM.

Unlike a single-hour spike, June 11 stayed above $200/MWh for eight straight hours, from noon to 8 PM. This represents a sustained heat day rather than one evening ramp and systemwide stress.

The second heatwave closed the month. A widely reported heat dome built over the central and eastern US, pushing PJM demand to its June peak: 144 GW on June 29 and 150 GW on June 30. That 150 GW sat in line with the PJM 2024 summer peak of 151 GW, though below the 166 GW all-time record from 2006.

Regulation spiked over June 10 and 11

Real-time regulation, a second-by-second balancing product distinct from reserves, spiked over two days. Daily averages hit $1,066/MW-day on June 10 and $1,185/MW-day on June 11, against a June 2025 monthly average of $55/MW-day for all of PJM.

Part of that rise is structural, not weather. PJM's regulation market redesign went live on October 1, 2025, merging the RegA and RegD signals into a single regulation product and retiring RegD's mileage premium. Clearing prices have run higher across the market since, so the redesign lifted June 2026's baseline while the mid-June heat drove the two-day spike on top of it.

June 11 alone cleared 3.1 times June 2025's highest single day of $379, set on June 24. It was a sustained event: more than 100 five-minute intervals cleared above $500/MW-day on June 11.

Outlook for summer 2026 in PJM

Real-time spreads eased 9%, demand fell 7%, and the maximum real-time price fell 61% year over year in PJM. Day-ahead spreads widened 24% as the market cleared a firmer daily shape.

For a 100 MW, four-hour battery, the $473/MW-day real-time spread maps $14/kW-month, before round-trip efficiency and cycling losses. Regulation, which clears across PJM, could have rivaled that on the spike days. The June 11 clearing of $1,185/MW-day was 2.5 times the month's average energy spread, so a battery offering regulation would have banked much of its June income in one or two days.

The late-June heat dome pushed demand to its monthly peak on June 30, but the top price that day was only $252/MWh. For most of PJM, June was quiet, with the mid-Atlantic still carrying the spreads.