Unit price deviation in the electricity bill is the situation where the kWh unit price reflected on the invoice does not match the supply contract, tariff table or market formula. For eligible consumers and SKTT subscribers, the formula (PTF+YEKDEM)×KBK is the reference; Periodic fixed unit price is valid in the national tariff. Variance detection requires period alignment and item-by-item control — looking at the total amount is not enough.
How is the expected unit price calculated?
The expected unit price is determined by subscriber status. For subscribers within the scope of SKTT, the formula (PTF+YEKDEM)×KBK is applied — as detailed in our SKTT and Free Consumer 2026 guide, PTF is an hourly multiplier, YEKDEM is a monthly multiplier, and KBK is a periodic multiplier. For free consumers who make bilateral agreements, the fixed, indexed or spot+P formula in the contract is the reference. EMRA approved unit price table is used in the national tariff. Calculation: period average or contract unit price × KBK (if any) = expected kr/kWh.
(PTF+YEKDEM)×KBK
SKTT formula
Cost based
15,000 kWh/year
industry limit
SKTT threshold
+3 months
Transition delay
After limit exceeding
Why is period alignment critical?
A significant part of the errors that appear in unit price deviation are caused by period drift: if the MTF average is compared with December data while the invoice covers January, a spurious deviation occurs. Correct method: match invoice period dates (start-to) with supplier invoice and OSOS export; Use PTF and YEKDEM values in the same range. Our glossary article on what is PTF summarizes the hourly structure and EPİAŞ source; YEKDEM is updated with a monthly announcement.
How to check item-based unit price?
Unit price control should be done not only on the active energy line but on all cost items. Active energy: kr/kWh in the invoice ÷ supply contract unit price. Distribution: contract strength and consumption-based tariff components. Reactive: unit reactive energy cost (kurus/kVArh) with current tariff table. Power: unit price for exceeding demand. Each item is checked on a separate line; The total unit cost (total amount ÷ total kWh) can be misleading because the reactive penalty and power overrun inflate the average.
| pencil | Expected resource | Control formula | Frequent reason for deviation |
|---|---|---|---|
| active energy | Supply contract / SKTT | Bill kr/kWh vs expected | PTF period shift |
| YEKDEM | EPİAŞ monthly announcement | Announcement vs invoice component | Late announcement reflection |
| Distribution | Distribution tariff | kW × tariff + kWh component | Incorrect contract strength |
| reactive | EnergyTariff table | kVArh × unit price | over limit |
| power over | EMRA power fee | Excess kW × unit | peak hour peak |
How to verify SKTT and free consumer unit price?
For SKTT subscribers, the unit price depends directly on the market cost; The monthly invoice is compared with the EPİAŞ PTF average and YEKDEM announcement. In the industrial and commercial group, exceeding the annual limit of 15,000 kWh triggers the SKTT transition; The transition is applied starting from the first day of the third month following the limit exceeding month. Annual consumption trend and limit proximity can be monitored in our SKTT limit control tool. For subscribers who have bilateral agreements, the unit price formula may change during contract renewal periods — add the renewal date to the reconciliation calendar.
How does the objection process work when a deviation is detected?
When a unit price deviation is detected, a written objection is directed to the supplier or distribution company. Attachments: invoice PDF, OSOS consumption export, expected unit price calculation table, relevant article of the supply contract. The objection period is limited from the invoice date; Early detection increases the chance of correction before payment. The approved correction may be reflected in the next invoice or come as a separate offset document — keep track of either situation.
Regular unit price control is much more effective than a once-a-year audit. A monthly routine prevents small deviations from accumulating and turning into large costs; It is of critical importance, especially in periods of PTF and YEKDEM fluctuations for free consumer subscribers.
What is the difference between manual control and software?
Manual Excel control works on small portfolios; However, since PTF changes hourly, monthly average calculation carries the risk of error. Software-based control automatically matches OSOS consumption profile and invoice items and performs period alignment. On ten subscribers the manual process takes hours per month; automatic reconciliation takes minutes. An audit trail also occurs naturally in the software process.
How to detect unit price deviation in national tariff?
For national tariff subscribers, the unit price is read from the EMRA approved tariff table; It is fixed unless there is a tariff change during the period. Deviation is usually caused by wrong subscriber group (residential/industrial), incorrect kWh or old tariff application. The 2026 SKTT limit for residential subscribers has been updated to 4,000 kWh/year — when the limit is exceeded, the unit price structure changes completely. Confirm with the distribution company and your annual consumption trend whether you are staying on the national tariff.
How to prioritize deviation in a multi-site portfolio?
In a multi-facility portfolio, each subscriber's unit price deviation is calculated separately; The facilities with the highest deviation are prioritized. Ranking criteria: deviation amount (TL), deviation rate (%), recurring deviation (is there any previous month). Without a central panel, this prioritization cannot be managed with Excel — formula confusion over ten sites is inevitable. Working with OSOS consumption monitoring, the invoice module produces a portfolio-based deviation report.
What is the hidden cost of unit price deviation?
Seemingly small unit price differences (for example, at the level of kuruş/kWh) turn into thousands of lira per month in high consumption facilities. Reactive penalty and power overage items create additional costs independent of the unit price variance — if all three are not controlled together, the total variance will swell. Unit price accuracy directly affects profitability in the industry, where the share of energy expenses varies between 5-20% on a facility basis. A monthly routine inspection is much more effective than a one-time annual inspection.
How does software-based drift detection work?
Software-based variance detection automatically calculates the expected unit price when the invoice is uploaded and compares it to the invoice value. OSOS consumption data provides kWh verification; The supply contract or SKTT parameters determine the expected price. An alarm is generated when the deviation threshold is exceeded; In a multi-facility portfolio, priority is determined by ranking. Compared to manual accounting, the risk of period drift is eliminated because the system automatically aligns billing dates with the OSOS range.
Sample reconciliation flow: step by step
- Download invoice PDF; Note the term dates.
- Get OSOS export; Match total kWh.
- Calculate the expected unit price (contract or SKTT formula).
- Compare with bill kr/kWh; If there is a deviation, separate it by item.
- Check reagent and demand items separately.
- Prepare deviation documentation; If necessary, initiate an appeal.
Conclusion
Unit price deviation detection is based on the trio of expected price calculation, period alignment and item-based control. (PTF+YEKDEM)×KBK formula for SKTT and eligible consumer subscribers; The periodic table in the national tariff is a reference. Preparing the appeal package early when a deviation is found limits cost loss. Use the table in this guide as a control matrix for your next billing cycle.