PJM batteries have seen revenues sharply increase, the October 2025 regulation market redesign is the structural driver behind the lift. Pre-redesign (April 2024 to September 2025), fleet revenues averaged $20/kW-month. Post-redesign revenues averaged $62/kW-month, peaking at $104.5/kW-month in February.

Energy arbitrage has strengthened too. A mid-month heatwave drove April's TB4 spreads to $383/MW-day, 62% above April 2025.

April’s modeled revenue stack adds up to $72/kW-month. Regulation contributes $56/kW-month of that total, with $11/kW-month from real-time energy arbitrage and $5/kW-month from capacity payments.

Key takeaways

• PJM batteries are earning roughly 3x what they earned last year, with regulation alone driving the lift.
• April's modeled revenue stack hit $72/kW-month, lifted by stronger regulation revenue and wider TB4 spreads.
• April's real-time TB4 spreads averaged $383/MW-day, 62% above April 2025. Baltimore (BGE) led zonally at $658/MW-day, more than double last April.
• The wider spreads came from a mid-month heatwave (April 15-16), evening clearing prices roughly 70% above April 2025, and continued midday solar growth pulling daytime troughs lower.

The October regulation redesign lifted fleet revenue to 3x the pre-redesign baseline

PJM’s October 2025 regulation market redesign replaced the separate Reg A (slow, thermal) and Reg D (fast, battery) signals with a single unified signal. Q1 2026 actuals quantify the impact.

The 18 months of pre-redesign data put fleet revenues in a $13-$37/kW-month range, with regulation contributing an average of $15/kW-month. Since the redesign, revenues have averaged $62/kW-month, with regulation alone averaging $55/kW-month.

Ancillary service clearing prices drive this increase. The minimum monthly regulation clearing price post-redesign ($62/MWh) is higher than any monthly price since January 2023.

Synchronized and primary reserves remained low as they were unaffected by the redesign.

Morning and evening ramp hours have continued to produce sharp price spikes since October. Additionally, the baseline during non-ramp hours has also moved up. Batteries are earning from both the ramp spikes and the higher baseline.

TB4 spreads widened on a mid-April heatwave and increased solar generation

April’s real-time TB4 spreads averaged $383/MW-day, up from $358/MW-day in March and 62% above April 2025’s $237/MW-day. Day-ahead spreads ran $247/MW-day, also above March and 51% above last April.

The zonal picture was familiar. Baltimore (BGE), Washington DC (PEPCO), and Virginia (DOM) led at $658, $605, and $601/MW-day respectively. Baltimore and DC more than doubled year-over-year (+108% and +112%).

Every PJM zone saw real-time spreads rise YoY, but the Mid-Atlantic moved further. Persistent transmission constraints between eastern load centers and western generation continue to drive price separation during ramp hours.

Day-ahead spreads tell a milder version of the same story. Mid-Atlantic zones still lead, but the geographic gradient is shallower and zone-to-zone differences are narrower than in real-time.

April had no equivalent of March’s Winter Storm Iona, with limited extreme weather fluctuations. The clearest single event was a mid-month heatwave on April 13-17. Mean hourly load reached 101 GW on April 15, the highest of the month versus the typical April baseline of around 85 GW.

Day-ahead markets clearly responded, peaking at $249/MWh, the monthly high. Real-time followed suit, peaking at $353/MWh on the evening of April 15.

Beyond the heatwave, the intraday shape itself shifted year-over-year. Average evening prices in April 2026 ran roughly 70% above April 2025, with the 7-8 PM window averaging near $115/MWh versus $65 last year.

Most days followed a similar hourly shape to 2025, but with a higher evening ramp.

Renewables also widened TB spreads. Solar generation grew 27% YoY in April (mean hourly output rose from 3.3 to 4.2 GW), with more midday output pushing daytime prices lower. Wind grew 16%; gas and nuclear ran flat.

The shifting generation fleet compounds the heatwave-driven peaks and makes TB spreads larger YoY.

Mid-Atlantic projects are best-positioned for the highest spreads in PJM

The same zonal pattern holds at the asset level. Each operating BESS in BGE, PEPCO, and DOM cleared roughly double the cumulative April TB spread of operating batteries in COMED, AEP, or APS. Planned projects in those same Mid-Atlantic zones would clear the highest spreads in the pipeline today.

What does April tell us?

Six months on, the data confirms PJM's October 2025 regulation reform delivered for batteries. Pre-redesign monthly revenues averaged around $20/kW-month. They have since tripled, with regulation accounting for nearly 100% of the increase.

April's energy market dynamics also signal an increasingly lucrative environment. TB4 spreads widened year-over-year, driven up by a mid-month heatwave during planned outage season and continued midday solar growth pulling troughs lower.

Looking forward, Phase 2 of the redesign, due October 2026, will split regulation's bidirectional signal into separate RegUp and RegDown products. Whether that adds further upside or pulls clearing prices back is the open question for late 2026.