It is always a matter of question that for how long the current energy sources, primarily the nonrenewable sources can fulfill our demand for energy. And will the renewable sources be enough to furnish the demand? It is a known fact that the nonrenewable sources are not enough to fulfill the future demands and are also one way or the other harmful to the environment. In order to meet the demands the renewable sources are tapped but the question remains the same- for how long will they feed our energy requirements. The other question that creeps into the picture is that can we totally depend on the renewable sources for our future energy needs? Let us review the renewable sources and see for how long they can help us. Wind power: It has been already proved that wind power can harness the demand for the whole nation’s needs and with the prevailing weather patterns it is a crucial source of energy. The offshore wind has the same potential of producing energy that the onshore wind has and it is evident from the windmills on the landscapes. In fact, the windmills on the landscapes provide more stable and predictive amount of electricity. Today, these windmills do cater to the needs of various large scale industries and are been tapped to supply energy to the small states. Solar energy: Where there is no scope of hydropower the wind and solar energy is easily available. The solar energy can reach any location and is the cheapest source of energy amongst all in the list. It can be equally by commercial and residential purposes. But, if we talk about for the longevity of this source then till the time the sun is available or its core doesn’t burn out and it reaches the state of supernova, this source of energy is available to us. Hydropower: The hydroelectricity is not a news for us and it is being tapped since years. It is one of the reliable sources of energy and one can rely upon the same till the entire water for the planes evaporates. And all the water bodies vanishes. Well if it evaporates, then the water will flow back to nature in the form of rain thus keeping the water balanced. Keeping aside the purity and cleanliness of water, the sources that are tapped or will be tapped in future are well enough to supply the energy for future demands. Biofuels: Till the time the natural debris is available for producing energy, this is the reliable source one can count upon. To keep the balance intact, more and more of the plants and trees needs to be planted. The balance will also help the environment from replenishing it with more of oxygen and keeping the environment safe. Geothermal energy: The source is available till the time the heat from within the grounds is available. This source of energy is used for power generation and for heating and cooling requirements. The heat produced will be there till the time the earth exists it can be a reliable source of energy to cater to our future demands. One thing has to be kept in mind to keep the sources running for long, to mot to waste the energy or to misuse the same. Then it will lead to exploitation of nature and may result in disasters.