C. Resource Uncertainty
All aspects of the power production process must be taken into account when choosing the megawatt capacity of a power plant, and this may lead to the preference for a smaller sized plant—regardless of economies of scale. Because the ultimate reservoir capacity characteristics and response to production can be uncertain at the start of a project, developers may opt to begin small and then gradually expand the use of the resource rather than risk (a) overusing the resource, or (b) spending money on costly power plant infrastructure only to find resource recovery is lower than expected due to misunderstandings of subsurface resource characteristics. In the past, some oversized projects have faced serious problems due to overuse.
The President of Iceland, in October 2007 remarks before the Senate Energy Committee, called the management of a geothermal resource
one of the most critical—and often overlooked—elements needed to maintain a geothermal resource.33 The power plant in the figure below, Nesjavellir, is part of one of the largest geothermal areas in Iceland.