Demand Charges: Why Using Less Does Not Help
A demand charge bills you for how fast you drew power, not how much you used. One bad interval can set the majority of your bill. Here is how to read it and what to do about it.
Who this is for
- ■Plant managers whose electric bill runs five figures or more each month
- ■Facility and operations leaders confused by bills that climb while usage falls
- ■Finance leaders forecasting energy costs at manufacturers, hospitals, schools and municipalities
- ■Anyone reviewing a solar, storage or rate proposal that promises demand savings
Do you understand where your demand charge comes from, and do you have any plan to control it?
There are three things on your utility bill. Fixed charges, unavoidable, assessed for being connected to the grid. Energy charges, billed per kilowatt-hour based on total consumption. And demand charges, billed per kilowatt based on the maximum rate at which you drew power at any single point during the billing period.
Most operators understand the energy charge intuitively. You use more, you pay more. Demand charges do not work that way. That is where the confusion lives, and that is why cutting kilowatt-hours does not automatically cut the bill.
Connection fee
Per kilowatt-hour
Per kilowatt
33%of this guide, read. The rest of it is below.
- 02 The mechanism Kilowatt-hours vs. kilowatts, and the interval that sets your month
Energy measures total consumption over time, in kilowatt-hours. Demand measures the rate of consumption at a given moment, in kilowatts. The difference is what an appliance illustrates in one line.
A central air conditioner rated at 3,500 watts running for 8 hours draws 28 kWh of energy. Add a 4,000 watts water heater running at the same time for one of those hours and your combined draw at that moment is 7.5 kW. Run the water heater before the A/C kicks on instead and demand over the same span never exceeds 3.5 kW. Same total energy. Different demand. Different bill.
Same energy used, very different demandSequencing loads instead of stacking them changes the peak without changing consumption. Most utilities measure demand on a 15 minutes interval, though some use five, thirty or sixty minute windows. Check your tariff. Whatever the interval, the highest average draw in any one of those windows becomes your billing demand for the entire month. One bad interval, even on one day, can define your costs for the next thirty.
For large commercial and industrial customers, demand charges commonly exceed 50% of the total electric bill. One vendor puts the range at 30% to 70%. That is not a rounding error. That is the majority of what you pay, driven by one peak.
How much of a C&I bill demand charges eat50%Commonly exceeds this share for large C&I30%Low end of typical range70%High end of typical rangeDemand can be the largest single component of the bill, not the smallest.Know which one is on your tariffThe five structures you may encounter
Structure How it is billed Watch for Max / non-coincident Highest draw at any point in the billing period One interval sets the month, any time of day Time-of-use Highest draw within a defined on-peak window Windows vary by utility, aligned to system peak Flat Single rate per kilowatt on one demand reading Simplest to model, easiest to underestimate Tiered Different rates above and below a threshold Crossing the threshold changes rate on the whole reading Daily Per kilowatt per day across the billing period Newer structure, expected to spread The one that catches operators off guardRatchets: a summer peak that follows you into winter
A demand ratchet is a minimum billing floor. Your actual demand in a given month may be far lower than what you are billed for. Two common types: a fixed kilowatt minimum, and a percentage applied to a reference demand from a prior period.
Here is a real tariff. Fixed minimum billing demand of 100 kW. In winter months, billing demand cannot be less than 70% of the highest metered demand from the prior summer. If August peaked at 400 kW, November billing demand is 280 kW, regardless of what you actually drew, which in the example was 150 kW.
What you drew vs. what you were billedA summer startup event can set the billing baseline for months. For large commercial and industrial customers, demand charges commonly exceed 50% of the total electric bill. One vendor puts the range at 30% to 70%. That is not a rounding error. That is the majority of what you pay, driven by one peak.
How much of a C&I bill demand charges eat50%Commonly exceeds this share for large C&I30%Low end of typical range70%High end of typical rangeDemand can be the largest single component of the bill, not the smallest.Know which one is on your tariffThe five structures you may encounter
Structure How it is billed Watch for Max / non-coincident Highest draw at any point in the billing period One interval sets the month, any time of day Time-of-use Highest draw within a defined on-peak window Windows vary by utility, aligned to system peak Flat Single rate per kilowatt on one demand reading Simplest to model, easiest to underestimate Tiered Different rates above and below a threshold Crossing the threshold changes rate on the whole reading Daily Per kilowatt per day across the billing period Newer structure, expected to spread The one that catches operators off guardRatchets: a summer peak that follows you into winter
A demand ratchet is a minimum billing floor. Your actual demand in a given month may be far lower than what you are billed for. Two common types: a fixed kilowatt minimum, and a percentage applied to a reference demand from a prior period.
Here is a real tariff. Fixed minimum billing demand of 100 kW. In winter months, billing demand cannot be less than 70% of the highest metered demand from the prior summer. If August peaked at 400 kW, November billing demand is 280 kW, regardless of what you actually drew, which in the example was 150 kW.
What you drew vs. what you were billedA summer startup event can set the billing baseline for months. - 04 The trap Solar alone is not a demand charge solution
Solar reduces energy charges well. It does not reduce demand charges as efficiently. Generation does not reliably line up with your peak demand window, especially under TOU tariffs where on-peak periods run into the evening after solar output drops. Passing clouds can create demand peaks rather than shave them.
Myth Reality Solar cuts my bill across the board, including demand. Solar cuts energy charges. It rarely moves the demand line the same way. If it generates during the day, it will catch my peak. Your peak may fall outside solar hours, or in a cloud dip that spikes draw. A vendor pro forma proves the demand savings. Pro formas often use generic assumptions, not your tariff, interval or ratchet. Battery storage is a different tool. A vendor case study from Sunlith Energy describes a manufacturer with monthly demand charges over $50,000 that installed a 5 MW / 10 MWh system, reported a 35% demand reduction, $500,000 in annual savings, and payback in 4 years. Treat vendor case studies as directional. The economics depend on incentives, tariff structure and whether the battery earns ancillary revenue too.
Vendor case study, treat as directional35%Reported demand reduction500,000$Reported annual savings4yearsReported paybackThe headline numbers move only when your specific tariff and load profile line up.The most accessible near-term lever is load sequencing. Do not run your largest loads simultaneously. Stagger startups. Schedule discretionary loads outside on-peak windows where your tariff defines them. These are operational decisions, not capital investments.
- 1 Pull the last twelve months of interval data from your utility and identify the top five intervals that set your billing demand.
- 2 Read your tariff for the demand structure, the measurement interval and any ratchet language.
- 3 Map your largest equipment startups against those intervals. Where can staggering or delay drop the peak?
- 4 Confirm your on-peak window if you are on a TOU tariff, and shift discretionary loads out of it.
- 5 Only then evaluate capital solutions like storage against your specific tariff and load profile.
The direction of travel is worth tracking in your service territory. Some utilities are shifting more cost recovery into TOU demand. Others have introduced daily demand structures. A few are extending demand charges to residential customers. The direction is uneven and contested, but if you are making a five to ten year capital decision on facility equipment, the tariff you have today is not necessarily the tariff you will operate under.
- 05 Your leverage The levers you actually have, and what to ask
The most accessible near-term lever is load sequencing. Do not run your largest loads simultaneously. Stagger startups. Schedule discretionary loads outside on-peak windows where your tariff defines them. These are operational decisions, not capital investments.
- 1 Pull the last twelve months of interval data from your utility and identify the top five intervals that set your billing demand.
- 2 Read your tariff for the demand structure, the measurement interval and any ratchet language.
- 3 Map your largest equipment startups against those intervals. Where can staggering or delay drop the peak?
- 4 Confirm your on-peak window if you are on a TOU tariff, and shift discretionary loads out of it.
- 5 Only then evaluate capital solutions like storage against your specific tariff and load profile.
The direction of travel is worth tracking in your service territory. Some utilities are shifting more cost recovery into TOU demand. Others have introduced daily demand structures. A few are extending demand charges to residential customers. The direction is uneven and contested, but if you are making a five to ten year capital decision on facility equipment, the tariff you have today is not necessarily the tariff you will operate under.
Decision matrixWhen to act on demand charges, and when to hold off
✓ Act now- Demand charges are more than half of your monthly electric bill
- Your tariff includes a ratchet and you cannot describe it from memory
- Your largest loads start together at shift change without a sequencing plan
- A vendor has quoted storage or solar and the model does not reference your tariff
- You are on a TOU tariff and cannot name your on-peak window
✗ Do not act yet- You have not pulled interval data or a full tariff sheet yet
- Your bill is dominated by fixed and energy charges, not demand
- A storage pro forma is based on generic assumptions not your load profile
- You are being sold solar as the primary demand charge fix
- What percentage of our electric bill is demand charges versus energy charges, and when did we last pull that number?
- Does our tariff include a ratchet, and what is our current billing demand floor based on prior seasonal peaks?
- Are our largest equipment loads staggered at startup, or coming on together and creating an avoidable peak?
- If we have been quoted a solar or storage project, did the financial model use our specific demand charge structure and rate, or generic assumptions?
- Decision matrix
When to act on demand charges, and when to hold off
✓ Act now- Demand charges are more than half of your monthly electric bill
- Your tariff includes a ratchet and you cannot describe it from memory
- Your largest loads start together at shift change without a sequencing plan
- A vendor has quoted storage or solar and the model does not reference your tariff
- You are on a TOU tariff and cannot name your on-peak window
✗ Do not act yet- You have not pulled interval data or a full tariff sheet yet
- Your bill is dominated by fixed and energy charges, not demand
- A storage pro forma is based on generic assumptions not your load profile
- You are being sold solar as the primary demand charge fix
Questions for your morning huddle- What percentage of our electric bill is demand charges versus energy charges, and when did we last pull that number?
- Does our tariff include a ratchet, and what is our current billing demand floor based on prior seasonal peaks?
- Are our largest equipment loads staggered at startup, or coming on together and creating an avoidable peak?
- If we have been quoted a solar or storage project, did the financial model use our specific demand charge structure and rate, or generic assumptions?
The one thing to rememberYour billing demand is set by the single worst interval in the month, and a ratchet can carry that peak forward for months.
This week, pull twelve months of interval data and your full tariff sheet. Identify the intervals that set your billing demand and check your tariff for ratchet language before you evaluate any project.
The Energy Decision BlueprintKnow if the numbers actually pencil out before you sign anything.
A written second opinion on the project in front of you, whether that is a rate change, new equipment, or a renewable installation.
- 01A short call, to figure out quickly whether we can actually be helpful. If we can't, we'll say so on the spot.
- 02We pull the data, your bills, your rate structure, vendor proposals, project specs.
- 03You get the verdict in writing: whether the payback will materialize, and the opportunities or risks nobody has raised.
Get a Blueprint at blueprint.tac-nrg.com Free for Indiana-based operations spending five figures or more a month on electricity. No obligation. You keep the write-up either way.- Demand charge
- A per-kilowatt fee on your utility bill based on the maximum rate of power draw during a billing period, separate from the per-kilowatt-hour energy charge.
- Kilowatt vs. kilowatt-hour
- A kilowatt is the rate of power draw at a moment. A kilowatt-hour is total energy used over time. Demand is billed on the first, energy on the second.
- Measurement interval
- The averaging window used to calculate demand, most commonly fifteen minutes. The highest interval in the period becomes billing demand.
- Max / non-coincident demand
- A demand charge based on the customer's single highest interval in the billing period, regardless of when the utility's system peak occurs.
- Time-of-use demand
- A demand charge measured only within a defined on-peak window set by the utility, generally aligned with the system-wide peak.
- Demand ratchet
- A minimum billing demand floor. Common types include a fixed kilowatt minimum and a percentage applied to a prior period's peak, which can carry a summer peak into winter bills.
- Peak shaving
- Using stored energy, load control or sequencing to hold your metered demand under a target ceiling and cut the demand charge.
- Load sequencing
- Starting and running large loads in sequence rather than simultaneously so that combined draw at any single interval stays lower.
- Behind-the-meter storage
- Battery energy storage installed on the customer side of the utility meter, used primarily for peak shaving and demand charge management in C&I facilities.