Because of increasing concern regarding greenhouse gas emissions and global warming phenomena in recent years, there is worldwide renewed interest in hydropower generation, especially in small hydro development. Small hydro offers significant benefits in terms of faster deployment, distributed generation, small business opportunities, and significantly reduced concerns about regional environmental/ecological system disturbances, although the levelized cost of energy (LCOE) from small hydro generation is usually higher than from large hydro.
Small hydro opportunities and development are not new. However, a large amount of small hydro resources is still untapped. A DOE assessment (2004) revealed that a total of around 165 GW of hydro resources was undeveloped, 47 GW of which is on the mini-hydro scale of less than 1 MW. A later study verified that more than 125,000 small hydro sites with a total 30 GW of potential were technically and environmentally feasible (DOE 2006, Kosnik 2010). Previous assessments have been limited to river and stream potential, but additional small hydro resources can be exploited in man made channels such as irrigation canals and municipal water and wastewater conduits.