What Each Half Actually Pays For
Supply — also called generation or energy charge — is the electricity itself: fuel, power plant operation, and the generator's margin. In deregulated states you can buy this from a competing supplier instead of your utility. In regulated states (Florida, Georgia, Alabama and others) the utility handles it and typically passes the cost through without markup.
Delivery — distribution, transmission, or the TDU charge in Texas — is everything that moves the electricity to your outlet: poles, wires, substations, the meter, and the crews who fix outages. Your local utility owns all of it. No supplier switch changes this line, because the same wires carry the power regardless of who generated it.
Why Delivery Now Exceeds Supply on Many Bills
This surprises people, and it's become common in the Northeast and California. Shipping the electricity genuinely costs more than making it in some territories.
The reason is that delivery is where utility capital spending lands — aging infrastructure replacement, storm and wildfire hardening, grid modernisation for EVs and electrification — and utilities recover that through rate cases. Requests reached a record ~$31 billion nationally across 2025, more than double the prior year. Supply, by contrast, is often a straight pass-through carrying no utility profit.
One Connecticut breakdown puts a typical Eversource residential bill at roughly 30% supply, 42% delivery and 28% taxes and public benefit charges. On a bill shaped like that, supplier shopping addresses under a third of the total.
When Switching Is Worth It — and When It Isn't
Worth considering if: you're in a deregulated state, your usage is high (savings scale with kWh), you're currently on a default or variable rate you never chose, and you can find a fixed-rate offer meaningfully below your current supply rate after fees.
Probably not worth it if: you're in a regulated state (there's nothing to shop), your usage is low enough that a few cents per kWh is trivial against a monthly fee, or the offer is a teaser that resets in three months to something worse than your default rate.
Three traps worth naming, because supplier-run comparison sites rarely lead with them:
- Teaser rates. 8¢ for three months, then 18¢. Read the contract term, not the headline.
- Monthly fees. A rate 1¢ lower with a $10 monthly fee is worse than your default rate below 1,000 kWh.
- Early termination charges. If the rate jumps after the promo period, leaving may cost you.
Also worth knowing: switching suppliers does not affect reliability. Your utility still maintains the wires and restores outages regardless of who supplies your power. That's a persistent myth.
The Half You Can't Shop
If delivery is what rose on your bill, supplier shopping won't help. Two things still do:
Use fewer kilowatt-hours. Delivery charges are mostly billed per kWh, not as a flat fee, so conservation reduces them — this is the part people miss when they conclude "delivery is fixed, so saving energy is pointless."
Use the programs your surcharges fund. A line item on your bill pays for state efficiency programs — free home energy audits, discounted insulation, heat pump and appliance rebates. You're funding those whether or not you claim them.
Fixed customer charges are the genuine dead weight: they don't fall with usage at all, and they hit low-usage households hardest in percentage terms. Nothing you do at home changes them.
Working Out What Changed on Your Own Bill
If your bill rose and you're not sure which half caused it, the fastest way to find out is to compare two bills a year apart and split the change into usage, supply rate, delivery rate and fixed charges. Our bill increase breakdown calculator does that attribution, and our article on why bills rise even when usage falls walks through a worked example.
For what's pushing rates up nationally — rate cases, capacity auction prices, and the contested role of data centre demand — see why electric bills are rising.