Market timeframe. The intra-day time frame is of significant importance to allow renewable generators to adjust their market position, but also to reduce the amount of balancing operations. An adequately functioning intraday market is a prerequisite to the full implementation of balancing responsibilities for all generators, notably because the correction of imbalance on this market proves to be less costly than through the activation of balancing mechanism, which is generally financed by the market parties out of balance (imbalance charges)6. When setting the timing for this timeframe, two major alternatives exist: • Continuous trading, i.e. bids can be submitted and matched by power exchange at any time before final gate closure time. For instance in Belgium, intraday platform becomes available for trading the day before delivery, at 14:00, and closes 5 minutes before is actual delivery. • Intraday discrete auctions, i.e. one or several auctions are called at specific predefined time. For instance, EPEX SPOT launched on German intraday market a complementary 15-min call auction at 3pm allowing market participants to trade the 96 quarters for delivery the next day simultaneously. Then, continuous trading session starts at 4pm until 30 min before delivery time. This examples (presented in Figure 8) shows the interest from participants to make use of 15-minute products Figure 8 Trading activity on the 15-minute intraday market, EPEX SPOT 2015 6 The Balancing process is generally financed through imbalance settlement. In some cases, its cost is also shared by all energy consumer through network charge Continuous markets (pay-as-bid) are simple to implement from a conceptual point of view. At least if only simple price-quantity orders are allowed. Including more complex types of orders may prove to be a challenge for the short-time period available to clear the market. There is a large international experience both at national and regional level with this type of markets (for instance in Northern and Central-West Europe). Discrete intraday auctions are also relatively simple to implement, but require more regional coordination (at least some homogenization is needed on the decisions on when to schedule discrete sessions of the markets). There is international experience at a national level (e.g. Spain, Portugal and Italy). The experience in the regional context is limited in Europe to the simpler case of two interconnected systems (e.g. Spain and Portugal). However, the proces...
