Conventional energy sources based on oil, coal, and natural gas have proven to be highly effective drivers of economic progress, but at the same time damaging to the environment and to human health. Keeping in mind, the social, economic and environmental effects of renewable energy system, early rural electrification programmes, relying upon grid-connected power, were once hailed as the catalytic drivers of rural development. However, experience has shown that their impact upon indigenous rural growth has been minimal and the associated benefits have not been forthcoming. Alternatively, the advent of commercially available renewable energy technologies has injected renewed optimism into the RE camp. Because they are able to devolve many of the income and employment opportunities associated with energy generation to the local community, it means that pre-electrification programmes using decentralized renewable energy systems, have the potential to succeed where conventional energies have failed. Environmental impacts of energy sources are commonly assessed on two scales or levels of aggregation. The first scale is the regional or national scale, which is an attempt to characterize the average impact of a typical facility or installation for the purposes of broad comparisons and planning. The second scale is on the local level, where site-specific impacts, such as effects on wildlife and local water supplies, can be assessed. Hydroelectric generation is the second largest in the world, providing 7% of domestic electricity production and much larger percentages. It is more efficient than any other form of electricity generation and offsets more carbon emissions than all other renewable energy sources combined.