Data Centers Added 9.7 Percent to PJM Wholesale Power Costs in the First Half of 2026
- Analysis Capacity & Wholesale Markets Policy & Markets
Marin Holt
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- 8 minutes read
- Data center share of wholesale cost, first half: 9.7 percent
- Data center adder, first half: 11.11 per MWh
- Total wholesale cost, first half 2026: 114.50 per MWh
- Increase over first half 2025: 50.3 percent
- Capacity cost increase: 207.1 percent
PJM’s independent market monitor put a number on data center load. Monitoring Analytics found that data center load raised wholesale power costs by $11.11/MWh in the first six months of 2026. That is 9.7 percent. The finding sits in its 2026 Quarterly State of the Market Report for PJM. The report covers January through June and came out on August 13, 2026. Total wholesale cost across the PJM footprint reached $114.50/MWh for the half, up from $76.16/MWh a year earlier. That is a 50.3 percent increase in twelve months.
Where the increase actually came from
The monitor broke the rise into parts, and the parts are not equal. Capacity costs rose 207.1 percent. Energy costs rose 47.7 percent. Transmission costs rose 5.6 percent. The real-time load-weighted average LMP went from $51.75/MWh to $72.54/MWh, a 40.2 percent increase.
Capacity is the outlier by a wide margin. It is also the market where the monitor has tied data center growth most directly to price. Across PJM’s last four capacity auctions, existing and forecast data center load raised capacity market revenues by a combined $29.4 billion. That figure is not new, and it is the clearest arithmetic link between load forecasts and customer bills that PJM has produced.
Two windows, two numbers
The published report covers January through June. The monitor also carried the analysis forward to July for PJM’s Members Committee in late August. Over seven months the data center adder came to $10.48/MWh, or 9 percent. Total wholesale cost across that window was $116.53/MWh, or $56.7 billion. The comparable 2025 period was $79.57/MWh, or $38 billion. That is a 46 percent gap.
Read the two windows together and the share edged down while the total kept climbing. Data centers accounted for 9.7 percent over six months and 9 percent over seven. The per-MWh adder fell from $11.11 to $10.48. Neither movement means data center load is receding. It means one additional month of higher non-data-center cost diluted the share. Anyone quoting a single percentage should say which window it came from.
The Gap
The 9.7 percent figure is narrower than it looks. The monitor attributes it to the capacity market. It does not fold in data center effects on energy prices or on transmission, which the monitor tracks separately. The real total is therefore higher than 9.7 percent, and nobody has published what it is.
Congestion is the piece most often skipped. Total congestion rose 179.9 percent, from $1.26 billion to $3.54 billion. Customers recovered only 55.7 percent of that through existing mechanisms. The remaining 44.3 percent stayed with load. Congestion is where new large loads and delayed transmission show up first, and it sits outside the 9.7 percent headline entirely.
Why It Matters
State regulators across PJM are writing large-load tariffs right now, and they need a defensible cost-causation number. The monitor has given them one, with a stated scope. Utilities arguing that data centers pay their own way will meet the $11.11/MWh figure in testimony. Consumer advocates will point out that it excludes energy, transmission and congestion.
The practical guidance is narrow. Cite the window and cite the scope. A 9.7 percent capacity-only share over six months is not the same claim as a 9 percent share over seven. Neither is the full cost of serving data centers in PJM. That last number remains unpublished. The 207.1 percent capacity increase suggests it is the one worth chasing.
Critical Perspective
The 9.7 percent figure is a capacity-market number wearing a total-cost label, and the monitor says so plainly. Congestion rose 179.9 percent to $3.54 billion over the same period, customers recovered only 55.7 percent of it, and none of that sits inside the 9.7 percent. Neither does any effect on energy prices. The honest reading is that 9.7 percent is a floor rather than an estimate, and nobody has published the ceiling. That matters because the number is already moving into large-load rate cases as though it were the full cost of serving data centers. If the monitor can attribute $11.11/MWh inside the capacity market, why has no one produced the matching figure for congestion, where costs nearly tripled and load absorbed 44.3 percent of the increase?
Sources
- Monitoring Analytics, 2026 Quarterly State of the Market Report for PJM: January through June
- Monitoring Analytics, PJM State of the Market report index 2026
- Monitoring Analytics press release, Market monitor finds PJM wholesale electricity markets competitive
- Utility Dive, Data center load made up 9% of PJM wholesale costs so far in 2026
- Utility Dive, Clear warning signs as PJM wholesale power costs jump
