Geothermal handbook: PlanninG and Financing power Generation t e c h n I c a L r e p o r t 2 / 2

utilization of residual heat from geothermal Power Plants
Although this handbook focuses primarily on electric power generation, the direct uses of geothermal 
heat—as well as the possible uses of residual or waste heat from power plants and the use of 
geothermal fluids for heating, cooling, and mineral extraction—are assessed by developers and 
policy makers in most geothermal energy producing countries. Once a geothermal power plant is 
operational, it can also be used in multiple ways to enhance the project’s overall economic result. This 
is referred to as multiple use, cascaded use, or utilization of residual and waste heat. 
Figure 1.16 is an idealized diagram showing cascaded use of geothermal energy, based on the 
example of a small (2 MW) binary power plant in Iceland. The plant is located as far as 18 km from its 
wells and uses the residual heat of the fluid (after power generation) for nearby industries (e.g., food 
industry), domestic heating for the entire town, fish farming, and snow melting on streets. As a result, 
the energy contained in the fluids is almost completely used. Geothermal power plants also can be 
connected to industries that produce waste heat, such as steel mills or waste incinerators. Their waste 
heat can be used to enhance the temperature of the geothermal fluid and increase power production.

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