What Drives Electricity Price Volatility in Ohio
The short answer
Ohio business electricity prices move for five main reasons: natural gas prices, which largely set PJM's wholesale energy price; PJM capacity auctions, which reset once a year; weather, which drives demand spikes and winter gas competition; utility delivery rates and riders, which change through PUCO cases; and data-center load growth, which is tightening supply. How much of that movement reaches you depends on your product: a fixed all-in contract absorbs most of it, while index pricing passes nearly all of it through.
This page explains where the volatility comes from. For the tools that manage it, see hedging strategies. For choosing between fixed and variable products, see fixed vs variable rates. For putting limits and approvals in writing, see writing an energy risk policy.
Driver 1: Natural gas and the wholesale energy price
Ohio is in PJM, where the wholesale energy price in each hour is set by the cost of the last generator needed to meet demand. Gas-fired plants are frequently that marginal unit, so electricity prices track gas prices closely.
The 2025 numbers show how much this matters. PJM's independent market monitor reported that the load-weighted average real-time price rose from $33.74/MWh in 2024 to $50.73/MWh in 2025, up 50.4%, and that 58.5% of the increase came from the fuel and consumables components of price. For more on gas specifically, see natural gas price volatility and Ohio electric bills.
Who feels it: index and variable-price customers immediately; fixed-price customers at renewal, when suppliers price new contracts off forward gas and power prices.
Driver 2: PJM capacity auctions
Capacity is the price of keeping enough generation available for peak demand. It's set in annual auctions for delivery years that run June 1–May 31:
| Delivery year | RTO capacity price ($/MW-day) | Approx. cost per kW of tag per year |
|---|---|---|
| 2024/25 | $28.92 | ~$10.56 |
| 2025/26 | $269.92 | ~$98.52 |
| 2026/27 | $329.17 (cap) | ~$120.15 |
| 2027/28 | $333.44 (cap) | ~$121.71 |
| 2028/29 | $325.00 (cap) | ~$118.63 |
Capacity isn't volatile hour to hour. It moves in large annual steps that are known well in advance: the 2028/29 price was set in July 2026. A price collar of roughly $175–$325+ per MW-day applies through 2029/30. The last two auctions cleared short of PJM's reliability requirement (by 6,623 MW for 2027/28 and 6,831 MW for 2028/29), which is why prices hit the cap. For auction details, see PJM capacity auction results.
Who feels it: everyone, eventually. Default-service customers see it in the June 1 price reset; contract customers see it either at renewal or immediately if capacity is a pass-through.
Driver 3: Weather
- Summer heat raises PJM demand and real-time prices on hot weekday afternoons. Those same hours set next year's capacity tags.
- Winter cold raises demand for gas for heating at the same time gas plants need it to generate power, which can push both gas and power prices up sharply for days.
Who feels it: index customers during the event; everyone through capacity tags the following June. See how weather drives Ohio business electricity use and, for index exposure in cold snaps, extreme weather preparedness.
Driver 4: Delivery rates, riders and transmission
The utility's share of the bill doesn't change with the market, but it does change:
- Base distribution rates change through rate cases. HB 15 requires every Ohio utility to file by the end of 2029 and every three years after, with a 360-day decision clock.
- Riders — for transmission, grid investment and other approved costs — can be updated more often.
- Some changes have lowered bills: HB 15 ended the OVEC legacy-generation rider on August 14, 2025.
Who feels it: everyone on the utility's system, regardless of supplier. These charges can't be locked through a supply contract.
Driver 5: Data-center load
Data-center growth is now the main reason PJM's capacity market is tight. The market monitor found that including existing and forecast data-center load in the 2026/27 auction's peak load forecast raised capacity market revenues by about $7.27 billion, or 82.1%. Nationally, Lawrence Berkeley National Laboratory estimated data centers used about 176 TWh in 2023 (4.4% of U.S. electricity) and could use 325–580 TWh by 2028.
In Ohio, PUCO approved an AEP Ohio data-center tariff in July 2025 that requires new data-center loads over 25 MW to pay minimum demand charges of up to 85% of contracted capacity for up to 12 years. That tariff protects other AEP Ohio customers from some stranded-cost risk, but it doesn't change PJM-wide capacity prices. See data-center growth and Ohio energy prices.
Your exposure by product type
| Product | Energy price moves | Capacity moves | Delivery moves |
|---|---|---|---|
| Default service (SSO) | Reset each June 1 through utility auctions | Included in the June 1 reset | Yes |
| Fixed all-in contract | Fixed for the term | Fixed for the term (unless a change-in-law clause applies) | Yes |
| Fixed energy, capacity and transmission passed through | Fixed | Changes each June 1 | Yes |
| Block-and-index | Blocks fixed; remainder floats hourly | Depends on contract | Yes |
| Index or variable | Floats with the market | Usually passed through | Yes |
| Expired contract on a supplier variable rate | Supplier sets monthly | Usually included | Yes |
Read your contract for pass-through, change-in-law and material-change clauses. They decide whether a "fixed" price can change mid-term.
Three checks to run now
- List which components are fixed and which float for every account, using the table above.
- Map contract expirations against June 1. A renewal that starts just after a capacity step-up prices it in; one that starts just before may not, depending on pass-through terms.
- Find your capacity tag. It's the one cost you can influence directly before next summer — see capacity tags explained.
FAQ
Why are Ohio business electricity prices so volatile?
Wholesale energy prices follow natural gas, capacity prices reset in large annual steps, weather drives demand spikes, and delivery rates change through PUCO cases. Your contract determines how much of that reaches your bill.
Are PJM capacity prices going to stay high?
The 2026/27, 2027/28 and 2028/29 auctions all cleared at or near the price cap, and a collar applies through 2029/30. Prices after that depend on future auctions and rule changes.
Does a fixed-price contract remove all volatility?
No. It fixes the supply price for the term, but delivery charges still change, and pass-through or change-in-law clauses can move part of the price.
Does the AEP Ohio data-center tariff lower my capacity costs?
Not directly. It sets minimum charges for large new data-center loads in AEP Ohio's territory; capacity prices are set PJM-wide.
Sources
- Monitoring Analytics, 2025 State of the Market Report for PJM, Vol. 1: https://www.monitoringanalytics.com/reports/PJM_State_of_the_Market/2025/2025-som-pjm-vol1.pdf
- PJM capacity auction results: https://www.pjm.com/markets-and-operations/rpm
- LBNL, 2024 United States Data Center Energy Usage Report: https://eta.lbl.gov/publications/2024-lbnl-data-center-energy-usage-report
- PUCO Case 24-508-EL-ATA (AEP Ohio data-center tariff): https://puco.ohio.gov/