UK Half Hour Day-Ahead 15:30 Auction

UK Half Hour Day-Ahead 15:30 Auction offers members an opportunity to trade half hour contracts in a local Day-Ahead auction. This auction provides members with the opportunity to balance their physical portfolios and optimise their generation portfolio to the half hour delivery period at the day-ahead stage.

Members submit anonymous orders of half hour contracts for delivery the following day. At 15:30 the market closes and the auction algorithm runs creating contracts based on matched orders. The market results are returned by 15:45 (UK Local Time).

How does it work?

The EPEX SPOT UK Half Hour Day-Ahead 15:30 Auction is a double-sided blind auction. Blind means that the Members cannot see the other bids/offers submitted. Buyers and sellers enter anonymous orders for each half hour period. Members can input several orders, with different prices, for each half-hour period, and thus build up an individual demand and/or supply curve per half hour period.

Spot Limit Orders

In this auction members can trade half hour instruments, which are traded for each half hour of the delivery day. Individual half hour instruments are traded in GBP per MWh with a precision of two decimals. This is referred to as Spot Limit Orders.

Half hour instruments are traded in lots of 0.1 MW (100 kW), or a multiple thereof, with a minimum lot size of 0.1MW. The price limits for the instruments are a minimum of GBP-500/MWh and a maximum of GBP3000/MWh.

Auction Indices

To serve Members, EPEX SPOT publishes a range of indices which can be used as a reference price for spot electricity. The EPEX SPOT UK Half Hour Day-Ahead 15:30 Auction Indices are a non-volume weighted arithmetic average of the market clearing price determined for each half hour instrument. The indices are Base Load (23:00 – 23:00 UK Local Time), Peak Load (07:00-19:00 UK Local Time), and Off Peak Load (23:00-7:00 + 19:00-23:00 UK Local Time).

ProcessTime: (UK Local Time)
Day prior to delivery- 15:30 Market Closure
- 15:45 Market Results
Business day after deliveryFinancial settlement

Clock Change

Normally, 48 half hours can be traded for each day. However there are two exceptions per year due to daylight saving. On the Sunday of the switch from wintertime to summertime, only 46 half-hours will be open for trading. On the Sunday of the switch from summertime to wintertime an extra 2 half hours are added to compensate for the switch.

Fee Schedule

UK Half Hour Day-Ahead 15:30 Auction is available to all full Members of EPEX SPOT UK at no extra cost. The Membership Fees for EPEX SPOT UK are listed in the table below.

EPEX SPOT UK Membership (per annum)Fee
Full Membership£25,750
Entrance fee£5,000
Technology (applied once per entity per year)£4,410
Forward Power Markets Transaction FeesTrading Fee (p/MWh)Clearing Fee (p/MWh)
Day-Ahead Auction1.500.50
UK Half Hour Day-Ahead 15:30 Auction1.500.50


All trades are notified to the industry ECVAA (Energy Contract Volume Aggregation Agent) immediately on behalf of Members. EPEX SPOT also offers third-party notification services, acting as the ECVNA (Energy Contract Volume Notification Agent).


In order to take part in the EPEX SPOT UK market, prospective members must first accede to the market rules of EPEX SPOT. The process for new members is the subject of a separate document (available on request).