This article discusses the growing need of energy in both developed and developing countries, and the acute population growth, which will exceed 10 billion by the year 2050. How can a world of 10 billion people be provided with adequate supplies of energy, cleanly, safely and substantially? There is a growing consensus that renewable energy sources will be a very important part of the answer. The growing interest in renewables has been prompted, in part, by increasing concern over the pollution, resource depletion and possible climate change implications of our continuing use of conventional fossil and nuclear fuels. Recent technological developments have also improved the cost-effectiveness of many of the renewables, making their economic prospects look increasingly attractive. It describes the achievement and progress made in hydropower, biomass conversion, geothermal, solar thermal technology, wind energy conversion, and the increasing usage of photovoltaics. It is evident that global warming is setting in and is going to change the climate, as well as the terrain of many countries, unless drastic measures are taken. The Kyoto meeting emphasized the importance of limiting CO2 emissions and to abide by some form of agreement to reduce emissions. The present study concludes that renewable energy penetration into the energy market is much faster than was expected in recent years and by 2030, 15-20% of our prime energy will be met by renewable energy.