A cogeneration system based on a natural-gas turbine with compression or absorption chillers seems to be a very promising route to satisfy the needs for electrical, heating and cooling energy in a building or group of buildings. These systems are particularly efficient in buildings that have a constant electrical, heating and cooling demand throughout the year. We have looked at the economics of installing a so-called trigeneration system in one of Sloveniaćs biggest hospitals. In order to fully address the heating needs we have suggested the inclusion of an additional gas boiler, and the possibility of cold storage has also been considered. Our goal was to calculate the prices of the energies produced from such a trigeneration system. The emphasis was placed on the price of cooling energy and its variation during peak and off-peak periods when using different types of cooling devices.