Alternative energy sources or non-conventional energy sources are being developed as alternatives to conventional energy sources (most of which are fossil fuels). Alternative energy sources include solar energy, wind energy, nuclear energy, geothermal energy, wave energy, tidal energy, fuel cells, etc. There are several issues with the use of thee alternative energy sources. They are expensive to develop, i.e. the capital cost of installation and operation and maintenance costs are high. Many of these sources (such as wave and geothermal) are very localized, i.e. can not be used everywhere. They also suffer from low efficiency, esp. solar energy (where the maximum practical efficiency is in the range of 20-30%.). Acceptability by public is another issue, esp. for nuclear power and wind turbines. There are also risks of hazards with nuclear power. Wind power creates noise pollution. Additionally, several of these sources are in development phase and may take some time before tey can be developed at large scale.
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The main disadvantage of using an alternate source of energy is that is is hard to produce large amounts to support entire cities and neighborhoods. It would become too expensive when compared to the ease with which the traditional fossil fuel generators produce energy.