05 / Tariff modeling / Data center power
GRID / OHIO
What a hypothetical 100 MW data center pays under Ohio Power Company’s (AEP Ohio) 2025 data center tariff, and what a supply contract, a market choice or a flexible load changes.
Live site / the study
01 / The question
What does a data center owe for capacity it does not use?
AEP Ohio’s data center tariff, ordered on July 9, 2025 and effective July 23, 2025, ties the bill to contracted demand, not to what a site draws. Minimum ramp commitments of 50%, 65%, 80% and 90% over four years, eight post-ramp years, exit charges and financial assurance mean a developer pays for a commitment even when load falls short.
02 / What the model does
One facility, 8,760 matched hours, five questions.
A Python cost-to-serve model prices a 100 MW facility hour by hour across 2025, then the site recomputes the tariff and stress cases in the browser.
| Section | What it does |
|---|---|
| Tariff lab | Rebuilds the primary-service bill at $6.33/kW-month and $138.50 a month. Contract demand above the actual peak adds a charge that does not fall with demand; billed demand is 85 MW for 11 months, then 82.5 MW, assuming a prior 100 MW peak. |
| Contracts | Compares fixed-price, index-plus-adder and block-plus-index supply, with a 70 MW fixed block covering 77.8% of annual energy. |
| Stress tests | Moves gas and capacity prices, and curtails 20% of load in the ten highest system-demand hours. |
| Markets | Prices the same 788,400 MWh at PJM’s AEP-Dayton Hub and MISO’s Indiana Hub. |
| Evidence | A searchable register of 47 assumptions, CSV and JSON downloads, and the model’s own caveats. |
03 / The results
Partial price protection helps. Capacity and location still matter.
| Test | Result |
|---|---|
| Minimum-demand charge, 100 MW contract vs 50 MW peak | +$2.64M a year |
| Gas +30%, PJM, index plus adder | +$3.75M a year |
| Gas +30%, PJM, 70 MW block plus index | +$0.83M a year |
| Capacity price +50%, fixed energy price | +$2.74M a year |
| PJM vs MISO energy price | $45.74 vs $44.36/MWh, $1.09M lower in MISO |
| 20% curtailment in 10 peak hours | $48,112 (PJM), $46,046 (MISO) gross, before operating costs |
The block cuts the gas shock from $3.75M to $0.83M, but it does not touch the capacity charge, and the energy-price gap between hubs is not a ranking of sites. Flexibility’s gross savings are small next to the fixed charges, and the study picks the peak hours with hindsight.
04 / Validation
Checked against the Python model it came from.
The browser model is tested against the original Python model: 54 published sensitivity cases, 108 combinations recomputed from the hourly model, and 350 twelve-month tariff paths. A 10,000-trial Monte Carlo (paired seven-day bootstrap, 15% price sigma, 5% load sigma) is shown as a conditional synthetic result, not a calibrated probability. Fixed and block rates are benchmarks held constant under stress, not supplier quotes.
05 / The recommendation
Proceed to phased due diligence, not a construction commitment.
Obtain quotes for a 70 MW block-plus-index structure and a fixed-price alternative, price the signed ramp and minimum-demand obligations before reserving capacity, and compare confirmed energization dates, connection costs and site-specific prices before choosing a location. Confirm service voltage, the current tariff and dated quotes first.