There are estimated to be 45000 large dams in the world, most of which have no electricity generating capability. In a number of countries, hydropower is a major supplier of base load, but in countries less reliant on it as a basic energy source the benefits of large scale hydropower and the way in which it is increasingly being used is as load levelling plants in times of high demand or generating plant breakdown when they can be brought in to the network in a matter of seconds. However, new hydro capacity is very expensive to install and often can only be justified on the basis of multiple use, for instance by using the water body for drinking water, irrigation recreation facilities or tourism and even then there are often objections on environmental grounds. Similarly, the investment cycle for large hydropower is long.
Small scale hydropower in generally used to supply local requirements by utilising small rivers, streams etc. For our purposes they do not constitute a major, consolidated opportunity.