Why your bill is changing
Why using less energy doesn't always lower your bill
You cut your usage, but the bill barely moved. It feels unfair — but it isn't a trick. It's the difference between a utility's fixed and variable costs, and how bills recover each.
The short answer: a large share of what it costs to run a utility is fixed — the poles, wires, substations, and capacity are built and paid for whether or not you flip a switch. Only the variable part (mostly fuel) rises and falls with usage. Because your bill has to recover a lot of fixed cost, using less energy shrinks the energy charge but not the fixed part — so the bill drops less than you'd expect.
Fixed vs. variable, in plain terms
Fixed costs
Incurred to have the system available: distribution poles and wires, substations, transformers, meters and billing, and much of the generating capacity to meet peak. Roughly the same month to month, no matter how much you use.
Variable costs
Rise and fall with how much electricity is actually produced and delivered — chiefly fuel and purchased power. These are what your per-kilowatt-hour energy charge recovers.
How the bill recovers each
A bill's customer charge (and, for larger customers, its demand charge) is designed to recover fixed costs — you pay it regardless of usage. The energy charge recovers variable costs, so it falls when you use less. The problem: since so much of a utility's real cost is fixed, but historically most of the bill is collected through the volumetric energy charge, the pieces don't line up. Cutting usage cuts the energy charge but leaves the fixed costs to be recovered anyway.
The rate-design tension
This is one of the hardest trade-offs in rate design. Recovering fixed costs through a higher fixed charge makes rates more stable and more cost-reflective — but it blunts the reward for conservation and weighs on low-usage customers. Recovering more through the energy charge rewards conservation — but can leave fixed costs under-recovered when sales fall, which pressures the utility to raise rates on everyone. There is no single right answer; a good rate design balances cost recovery, fairness, conservation goals, and bill stability for a utility's specific customers.
Frequently asked questions
Why did my bill barely drop when I cut my usage?
Because a large part of your bill recovers fixed costs — the poles, wires, substations, meters, and much of the generating capacity that exist whether or not you use electricity. Cutting kilowatt-hours lowers the energy portion of the bill, but not the fixed portion. So a big drop in usage often produces a smaller drop in the bill.
What counts as a fixed cost for a utility?
Fixed costs are those the utility incurs to have the system available: distribution poles and wires, substations and transformers, metering and billing, and much of the capacity needed to meet peak demand. They are largely the same from month to month regardless of how much energy any customer uses.
What counts as a variable cost?
Variable costs rise and fall with how much electricity is actually produced and delivered — chiefly fuel and purchased power. These are the costs an energy charge (per kilowatt-hour) is designed to recover, so they do go down when you use less.
Is a high fixed monthly charge fair?
It is a genuine trade-off, and reasonable people disagree. A higher fixed customer charge makes rates more stable and more closely tied to actual cost, but it weakens the reward for conservation and hits low-usage customers harder. A more volumetric design rewards conservation but can under-recover fixed costs if sales fall. Rate design is where a utility balances these goals for its own customers.
Keep reading
How your electric bill is built
See the fixed and variable pieces add up interactively.
What is rate design?
How utilities weigh cost recovery against conservation and fairness.
Rate360 helps utilities see their fixed and variable cost split clearly and design rates around it. See the methodology