Mix of Thermal and Hydropower Plants

Norway is unique in having almost only hydropower plants generating all the electricity. But other countries that rely to a high degree on hydro must have other forms of generating plants in a mix that varies from country to country. Norway participates in the international wholesale electricity market Nord Pool together with Denmark, Finland, and Sweden, where in 2003 the hydro share was 46%, conventional thermal was 28%, nuclear power 24% (increasing when a new Finnish station is planned to come on stream in 2010), and wind power 2%. It is therefore of interest to include other forms of generation and to study how the running of such capacities interacts with the operation of hydropower plants. We will focus on the class of generators termed thermal plants. As mentioned in Chapter 1, the operational problem of hydropower plants with reservoirs is essentially a dynamic problem, while the running of thermal plants will mainly be a static problem. Hydro plants are usually energy constrained, while thermal plants are effect-constrained. Thus the interaction may be of a special type.