In Türkiye a megawatt-hour of electricity can be sold through a bilateral contract signed years before delivery, or on the intraday market an hour before it. Each market has its own horizon, price formation and risk. This page explains the markets run by EPİAŞ and TEİAŞ, and the imbalance and settlement rules that connect them, under the legislation in force as of October 2026.
The main question that separates the markets is when and how the price is set. In futures markets the price is fixed months ahead. The day-ahead market sets one price for each hour of the next day. On the intraday market and on the balancing side, the price forms closer to delivery and in real time.
Day-ahead market (GÖP)
The day-ahead market matches supply and demand for each hour of the next day and sets the market’s reference price. Participants submit buy and sell bids to EPİAŞ by 12:30 on the day before delivery. Results are published at 14:00. A single market clearing price (PTF) forms for each hour, and every trade matched in that hour settles at this price.
Three bid types are used. Hourly bids hold separate price-quantity pairs for each hour. Block bids cover several consecutive hours at one price and quantity and are accepted or rejected as a whole. Flexible bids offer a quantity under a price condition and leave the matching hour to the algorithm.
EPDK sets the price range. Under Board Decision 14459 of 2 April 2026, the maximum price limit has been 4,500 TL/MWh and the minimum 0 TL/MWh since 4 April 2026. The same limits apply in the balancing power market. The maximum stood at 3,000 TL/MWh in early 2025 and 3,400 TL/MWh from April 2025. Because the floor is zero, prices in Türkiye cannot go negative.
As solar capacity grew, the daily price profile of the day-ahead market changed. In April 2026 the average PTF at 12:00 fell to 99 TL/MWh while the 19:00 average reached 3,129 TL/MWh. The hour in which energy is produced has become the main driver of its value within the same day.
PTF is the common reference for bilateral contracts, futures and imbalance settlement.
Intraday market (GİP)
The intraday market is used to correct changes that arise after the day-ahead auction, up to delivery. It opens at 18:00 on the day before delivery, and each contract trades continuously until 60 minutes before its delivery hour. Instead of a single-price auction, buy and sell orders match instantly and each trade executes at its own price.
Generators use it to adjust positions to updated forecasts or to cover volume lost to an outage. For flexible assets such as batteries it is a second pricing opportunity after the day-ahead price.
The volume gap shows the intraday market’s role. In 2025, 229.9 TWh matched in the day-ahead market and 16.2 TWh in the intraday market. It is a correction market: depth varies from hour to hour and large positions can move the price.
Balancing power market and SMF
TEİAŞ’s National Load Dispatch Centre keeps generation and consumption in balance in real time. After the day-ahead results, balancing units submit their final day-ahead generation or consumption schedules (KGÜP) and balancing market offers to TEİAŞ. Offers hold prices and quantities for increasing output (up-regulation, YAL) and reducing it (down-regulation, YAT).
When the system is short, TEİAŞ dispatches the cheapest up-regulation offers first; when it is long, it uses down-regulation offers. Instructions are tagged by reason: 0 for energy balancing, 1 for transmission constraints and 2 for ancillary services. The system marginal price (SMF) is set by the 0-tagged instructions in the net direction. When the system is balanced, SMF equals PTF.
Instructions are paid as bid. A plant receiving an up-regulation instruction sells the extra output at its offer price. A plant receiving a down-regulation instruction buys back the energy it does not produce at its bid price. SMF sets the imbalance price for participants who receive no instructions.
Imbalance
Each participant is responsible, per settlement period, for the difference between the energy it sold and bought and the energy it actually produced or consumed. This difference is the energy imbalance, settled at a price linked to PTF and SMF. Surplus energy is priced off the lower of the two, missing energy off the higher, each with a coefficient.
Under-delivery → MAX(V, PTF, SMF) × (1 + kᵤ)
Over-delivery → MIN(PTF, SMF) × (1 − lᵤ)
Since 1 January 2026 the coefficients have been set per settlement period according to the system’s direction. k and l, previously 3% in every hour, are now 6% when a participant deviates in the same direction as the system and 3% when it deviates against it.
Coefficients are set by EPDK Board decision and can change. Calculations should use the current decision.
For renewables the change feeds straight into revenue. On a sunnier-than-forecast noon, most plants in a region over-produce at once and push the system long. In those hours surplus output settles at a low price and with the higher coefficient.
Generators also pay a deviation charge (KÜPST) for deviations from their final generation schedule. The tolerance band is set by Board decision for each source type, and deviations beyond it are invoiced separately.
Imbalance can also be settled within a portfolio rather than plant by plant. In balancing responsible groups (DSG), members’ deviations net within the group; from 2026, a participant whose individual imbalance ratio exceeds 5% bears its own imbalance. The Regulation on Aggregation Activities, in force since 1 January 2025, makes the aggregator responsible for imbalance and KÜPST at portfolio level.
From 2026, the coefficient for deviating with the system is twice that for deviating against it.
Ancillary services
To hold frequency at 50 Hz, TEİAŞ procures reserve capacity separately from energy. Primary frequency control (PFK) responds automatically to a frequency deviation within seconds. Secondary frequency control (SFK) follows TEİAŞ’s automatic generation control signal and brings frequency and exchanges with neighbouring systems back to schedule.
Reserves are selected through TEİAŞ procurement with hourly and block offers. Selected participants receive a capacity payment in TL/MW for the capacity they hold. A unit must hold a valid ancillary service certificate and meet the parameters set in performance tests. Storage facilities can take part.
Ancillary prices were highly volatile in 2026. The hourly secondary reserve price was below 1,000 TL/MW in early January and above 4,700 TL/MW in the third week of February. Reserve volume is capped by system need: in the week of 27 April – 3 May 2026 the average hourly primary reserve was 274 MW and the secondary reserve 942 MW.
Capacity held for secondary control cannot be offered to another market in the same hour or sold bilaterally. Ancillary services settlement is published monthly by EPİAŞ.
Bilateral contracts and futures
There are three ways to fix a price weeks, months or years before delivery. In bilateral contracts, volume, profile, term and price are set freely between the parties. Contract volumes are notified to EPİAŞ and taken into account in settlement; the parties manage counterparty risk themselves.
On the Power Futures Market (VEP) run by EPİAŞ, monthly, quarterly and yearly contracts trade with physical delivery. Power contracts on Borsa İstanbul’s derivatives market (VİOP) are cash settled: at expiry they close on the difference against the average PTF of the delivery period.
Futures reduce price risk but not volume risk. A standard contract assumes the same volume every hour, while a solar plant produces nothing at night and more than the contract volume at midday. Generators therefore sell the share of expected output they can forecast with confidence forward and the rest on the spot market.
Renewable energy guarantees of origin (YEK-G)
A YEK-G certificate is an electronic record proving that a megawatt-hour was generated from a renewable source. EPİAŞ runs the system; on the generator’s application, one certificate is issued for each MWh of renewable output. Certificates transfer on the organised YEK-G market or bilaterally and are redeemed when used against consumption.
The certificate is separate from the physical sale of electricity. A plant can sell its energy in the day-ahead market and its YEK-G certificates to a different buyer. Corporate consumers use them to report renewable consumption. Under the 2026 tariff the YEK-G trading fee is 1.00 TL/MWh and the annual participation fee 3,000 TL.
The calendar of a delivery day
Trading for a single delivery hour begins months ahead across different markets and is finalised in the middle of the month after delivery.
Collateral and payments for organised market trades run through Takasbank. Day-ahead and intraday trades are paid daily as advances; at month end, imbalance and other items are calculated with meter data. For August 2026, the preliminary settlement notice was published on 11 September and the final settlement notice on 15 September.
From an investor’s perspective
The revenue of a generation or storage asset depends on which of these markets it can access and on where and in which hour it sells the same megawatt. Four rules stand out in a feasibility study.
First, the price range. A zero floor and a 4,500 TL/MWh cap limit both the value of midday solar output and the widest spread a battery can capture. Because the limit can change by Board decision, long-term models should not treat it as fixed.
Second, forecast quality. With the 2026 coefficients, deviating with the system costs more. Forecast accuracy and portfolio netting are now direct revenue items.
Third, ancillary depth. Reserve need is capped by system security and does not grow as storage capacity grows. Today’s capacity prices should not be used as a long-term revenue assumption.
Fourth, the spread of horizons. Fixing part of revenue through bilateral or futures contracts, rather than leaving all of it to spot prices, makes cash flow predictable for financing.
At Frekans we manage our customers’ assets across all of these markets within one commercial framework: from forward sales and bilateral contracts to day-ahead and intraday bids, from imbalance and settlement checks to YEK-G sales. Talk to our team to assess how much value your asset can create in each market.