The uniform price algorithm is used for day-ahead and within-day products.


General Information

Placing bids




  • The Shippers place their bids during the bidding round
  • Uniform price auctions only have one bidding round in which up to 10 bids (surcharge + amounts) can be placed
  • Each bid contains a surcharge, a minimum amount and a maximum amount
  • The evaluation of the placed bids and the allocation of capacity is done after the bidding round is closed


Bid consolidation and ranking




  • After closing the bidding round all received bids are evaluated
  • The auction algorithm ranks all bids (from all Shippers) according to the surcharge of the individual bid
  • Depending on the received bids the clearing surcharge is determined by either the fill-or-kill procedure or the pro-rata procedure


Example 1: fill procedure



  • B2 is the equilibrium bid, since the sum of the maximum amounts of A1, B1, A2 and B2 would exceed the available capacity
  • The “fill” procedure is used, because the sum of  the maximum amounts of A1, B1, A2 and the minimum amount of B2 is not exceeding the available capacity
  • The clearing surcharge is set to the surcharge of B2





  • All successful bids are allocated at the clearing surcharge
  • B2 is “filled” until the sum of  the maximum amounts of A1, B1, A2 and the part of B2 equal the available capacity


Example 2: kill procedure




  • The minimum amount of B2 exceeds the available capacity, therefore it cannot be the equilibrium bid
  • B2 is taken out of the evaluation (“killed”)
  • The auction algorithm looks for the next bid, which minimum amount added to the sum of A1, B1 and A2 would not exceed the available capacity




  • B3 is the equilibrium bid, since the sum of the maximum amounts of A1, B1, A2 and B3 does not exceed the available capacity
  • B3 is fully allocated
  • The clearing surcharge is set to the surcharge of B3


Example 3: pro-rata procedure



  • B2 and A3 are equally ranked bids, because they have the same surcharge
  • In this case the pro-rata procedure is used for the allocation due to the non-discriminatory principles of the algorithm 



  • B2 and A3 are allocated pro-rata as long as the minimum amount is fulfilled for both bids




  • The clearing surcharge is set to the surcharge of B2 and A3


Example 4: demand lower than available capacity




  • In general the clearing surcharge equals the lowest surcharge of all successful bids
  • In the case that the demand is lower than the available capacity, the starting price of the auction (e.g. regulated tariff) is the clearing price (no surcharge is applied)


Example 5: competing auctions (1:n auctions)

Competing auctions



•The two auctions at the bundle AB and AC take place in parallel on the PRISMA platform, according to the rules and procedures of a standard uniform price auction as described in the NC CAM

•After the bidding round the results are analysed and it is checked whether the competition constraint - available capacity at A (100) - is solved


Placing bids




  • The Shippers place their bids during the bidding round
  • The evaluation of the placed bids and the allocation of capacity is then done in three steps:

1. Intermediate evaluation of bids




  • During the intermediate evaluation both auctions are evaluated independently
  • The maximum amount of the bid of Shipper 3 for bundle AC is exceeding the available capacity and is amended to 10 in order to meet the available capacity (taking into account, that the minimum amount of the bid is still met)


2. Bid consolidation and ranking


  • In order to resolve the competition the two auctions have to be evaluated together
  • In preparation of the evaluation all bids that were placed are internally consolidated


3. Determination of clearing price


  • The consolidated bids are evaluated according to the rules and procedures described in the NC CAM
  • The maximum amount of the bid of Shipper 2 is allocated, since the shipper is willing to pay the highest surcharge
  • The remaining capacity (20) is allocated according to the rules of NC CAM. In this case the allocation is done pro-rata to the remaining bids (40 and 10)