The Megawatt Wall: How the Utility Bill, Not the Truck, Decides Whether Electric Freight Beats Diesel
Electric trucks are supposed to be cheaper to run than diesel. But whether that's true at a given charging site depends less on the truck and more on which utility it plugs into — and across the country, that changes everything. Pricing 241 U.S. commercial electricity tariffs on the rate a megawatt truck charger actually pays, this study finds that the same fee that haunts passenger fast charging — the demand charge — can make electric freight cost more per mile than diesel, before the truck even moves.
Key findings
- At the near-empty utilization of a brand-new megawatt corridor site (a 3% load factor), the typical territory's electricity works out to 101 cents per mile — more than diesel's 89 cents — and beats diesel on fuel in only a minority of places. Electric loses in 59% of territories, before any margin. The truck's energy would undercut diesel easily at an average price; the demand charge, spread over a nearly empty connection, is what flips it.
- The result doesn't hinge on today's fuel price. Diesel would have to reach $6.06 a gallon — above even today's near-record $5.31 — before the typical early-corridor site beats it on fuel. Anchoring on a high diesel price is deliberately conservative; a cheaper, more normal price only widens the gap.
- The fix isn't a cheaper truck — it's control over the peak. A depot that spreads charging across the overnight window beats diesel in 99% of territories (about 31 cents per mile). The same physics that makes the corridor wall steep makes depot load-management hugely valuable.
- Subsidies barely move a corridor site, because the binding cost is the recurring demand charge, not the hardware. Permanent demand-relief and no-demand commercial EV rates do far more, dollar for dollar.
- A battery or power cap can climb the wall — but only by deploying multi-megawatt-hour capital, or slowing an 8-minute charge to 30 minutes, purely to dodge a billing artifact. That capital fighting the tariff is the rate-design failure this paper identifies.
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The Megawatt Wall: Utility Demand Charges and the Cost of Electric Freight Relative to Diesel Across United States Utility Territories
A demand-aware pricing analysis of 241 U.S. commercial electricity tariffs — the actual rates a megawatt truck-charging site is billed on — measuring, in cents per mile, when electric freight beats diesel and when the demand charge flips it.
Reproducibility
Code and a public data sample (39 encoded rate schedules) are openly available and reproduce the paper's results. The same repository and engine serve both this paper and its passenger companion, The Rate Wall:
GitHub: rightsitera-arch/rate-wall-reproducibility
Archived at Zenodo (DOI: 10.5281/zenodo.21667465) — activates on release
License: code MIT; data sample CC BY 4.0
How to cite
Lightfoot, J. (2026). The Megawatt Wall: Utility Demand Charges and the Cost of Electric Freight Relative to Diesel Across United States Utility Territories (RightSite Working Paper). https://github.com/rightsitera-arch/rate-wall-reproducibility
Transparency
The author operates RightSite, which uses the tariff library and pricing method described here; this competing interest is disclosed in full in the paper. The full 241-schedule library is proprietary, but every underlying tariff is a public utility document, and the released engine plus sample let anyone reproduce the method.