Hydropower and its constraints

Hydropower, although an ancient technology, will emerge as a strategically critical source of new electricity in the decades ahead, especially for developing countries and the former Soviet Union, where most of the world`s undeveloped potential exists. Although the global potential for hydropower is enormous, numerous factors may limit its exploitation. Nonetheless, much uncertainty surrounds existing estimates of potential. A number of key technologies, including pumped storage, refurbishment of old plants, and compensatory steps (such as reservoir redesign) to reduce the variable nature of river flow, have contributed to the successful exploitation of both large- and small-scale hydrologic resources. Despite such technological advances, social and environmental impacts are argued to be the principal constraints and sources of uncertainty affecting hydropower`s development. Large storage reservoirs exacerbate many problems, particularly in tropical regions. The impacts of hydropower can be categorized either as direct: those that arise during construction of the plant, filling of the reservoir, and changing of the river flow; or as indirect: those that affect the health and well-being of the community. Many of these problems, however, can be mitigated by improved planning that includes public participation at an early stage. Taking such externalities into account may prolong the planning processmore » and increase overall costs, which are already high owing to the capital intensity of hydropower. Indeed, finance has become a major constraint affecting the development of hydropower in regions of greatest potential. Nonetheless, because of its ubiquity and low impact on the environment (relative to fossil-fuel plants), hydropower will remain a critical supply of new electricity in the developing countries and the former Soviet Union and therefore needs to be better understood. 66 refs., 9 figs., 11 tabs.« less