It is considered renewable and potentially sustainable. On resettlement, the economic condition of the oustee should be better than it was previously. As negative effects of hydroelectric projects are often proportional to the area submerged, the area submerged per MW of generation could be a good criteria for choice of a hydroelectric project. The best of hydel projects could be the mini hydel projects or the run of river projects. Upgradation of existing capacity would be another alternative.
Experts agree that some of the mega hydel projects have unacceptably high negative impacts.
When that is the case, benefits of a single dam can be captured by two or three dams with much lower impact. According to Mr. Fabian Acker, an expert on the subject, the need to develop small hydro resources was becoming more urgent in third world because of rising populations and in the developed world because of growing awareness of environmental restraints. There is consensus that a sustainable hydel project should always be preferred over coal. Though the air pollution caused by coal burning thermal projects could be substantially reduced using modern technology, the plant would still let out large quantities of carbon dioxide, a green house gas. On the other hand, it can be seen that coal may be preferable if the hydel reservoir submerges large areas of tropical forests.