Time-of-Use Tariff & Peak Cost Calculator
Enter consumption and unit prices from your bill for each band. See what peak hours cost you, how much shifting load would save, and whether single-rate would be cheaper.
Typical hours shown; check the time bands on your own bill. Use the all-in unit price from your bill (energy + distribution), and be consistent: either all with or all without taxes.
Result
How does a time-of-use tariff work?
A time-of-use tariff splits the day into bands, each with a different unit price. In Türkiye the typical bands are T1 day 06:00–17:00, T2 peak 17:00–22:00 and T3 night 22:00–06:00. Hours can change between periods; use the bands on your own bill.
Peak covers the evening hours when the grid is most loaded and is the most expensive band. Night is the cheapest. The same kWh therefore costs different amounts depending on when you draw it.
How is it calculated?
Cost is calculated per band and summed: Cost = T1 kWh × T1 price + T2 kWh × T2 price + T3 kWh × T3 price. The saving from shifting is shifted kWh × (peak price − target band price).
Example: a site using 40,000 kWh a month in peak shifts 20% of it, 8,000 kWh, to night. If the price gap between peak and night is 2 per kWh, the monthly saving is 16,000. These prices are only an example; use your own in the tool.
Single-rate or multi-rate?
If most consumption falls in the day and night bands, the multi-rate tariff is usually better. Sites with a heavy evening shift that run hard in peak may find single-rate cheaper. Before deciding, enter at least 3–6 months of band consumption and compare the two.
Ways to cut peak load
- Load shifting: move flexible loads such as water tank filling, pre-cooling, charging and compressed air storage to night or day.
- Shift planning: move energy-intensive processes out of peak.
- Storage and solar: batteries or self-consumption solar reduce grid draw in peak. The benefit depends on generation and storage capacity during peak hours.
- Measurement and alerts: set automatic alerts for large loads still running when peak starts.
All of these start with one question: which load runs in peak? The bill does not say. An energy monitoring system that measures by line does. To check other items on your bill, try the reactive penalty calculator.
Related solution
Energy Bill Analysis →Frequently Asked Questions
What is a multi-rate (time-of-use) tariff?
A tariff where the unit price changes with the time of day. In Türkiye it has three bands: T1 day, T2 peak and T3 night. Peak is the most expensive band, night the cheapest.
Why are prices not pre-filled?
Unit prices change with each tariff period and differ by subscriber group and voltage level. Copy the band prices from your latest bill so the result reflects your own contract.
Is the multi-rate tariff always cheaper?
No. If a large share of consumption falls in the peak band, a single-rate tariff can be cheaper. Enter a single-rate price in the tool and it compares the two for your profile.
Which loads can be shifted out of peak?
Loads that do not have to run at a fixed time: pre-cooling in cold stores, filling water tanks, compressed air storage, charging forklifts and electric vehicles, some batch processes and heating with storage.
How do I know my real peak consumption?
The bill shows the total per band for the month. To see which machine or line runs in the peak band, consumption must be measured at least every 15 minutes at meter or line level.
See who runs in the peak band
SolarTools measures consumption by meter and line, shows which loads fall into the peak band and lets you set alarm rules for them. Free sign-up.