Interactions between the German Electricity Spot Market and the Reserve Energy Market

Eight years after market opening, Germany has well established spot and future markets for electricity. Besides OTC and Internet broker platforms the main market place is the European Energy Exchange in Leipzig (EEX) with its spot and future market. Less known is the reserve energy market in Germany. The four German transmission system operators (TSOs) EnBW, EON, RWE and Vattenfall purchase network services on the reserve energy market. Products with specific technical requirements are primary, secondary and tertiary reserve. (Details about the technical requirements and typical means for providing the required services will be presented.) Each TSO organises a separate auction for these products - for primary and secondary reserve half-yearly, for tertiary reserve daily. Due to the technical requirements the liquidity on these markets is limited, but especially on the tertiary reserve market it is recently growing significantly due to new participants marketing several smaller municipal and industrial reserve power plants as combined bids which meet the 30 MW min. capacity requirement. Every power plant or interruptible load could not only be offered as capacity on the reserve market but could also be dispatched for the spot market. Therefore the developments of prices on these markets are not independent and opportunity costs against the spot market can be estimated for different type of plants bidding in the reserve market. Another interaction between reserve and spot market is caused by the balancing price system in Germany. Prices for balancing energy meeting deviations between load, trading balance and production of a market participant are based on quarter-hourly reserve energy costs encountered by the TSO. As unbiased load and production forecasts are not strictly enforced by the TSOs so far, part of the planned demand could be met with balancing energy if EEX spot market prices rise above expected balancing energy prices. This interrelationship has a damping impact on extreme EEX prices. (Author)