Abstract
Primary control has, for some time, been considered a free service and markets have not been established for it. Manually activated tertiary reserve was used for both secondary and tertiary regulation. Although primary reserve has had its own marketplace since 2008, this market has not received much attention. The situation in the Scandinavian power system [Belsnes and Fosso, 2008'] has significantly changed as a result of increased trading capacity with Europe as well as a higher degree of penetration by local intermittent generation. Consequently, stability and services for system support have gained more focus and hydropower producers face new challenges. Two of these challenges are the pricing of system services and handling the different reserve constraints when bidding into other markets such as the spot market, the intraday market, and parallel reserve markets.