Compare the benefits and disadvantages to the different alternative energy technologies.

Alternative energies are an alternate approach the non-renewable sources of energy like fossil fuels. 
Solar energy uses the always available and indispensable solar energy but has high installation cost of the equipment which utilizes solar energy.
Wind energy- renewable and abundant, but again high cost of installation, and of no use when the wind is unavailable.
Hydroelectric energy- converts hydro energy into electric energy. It uses the kinetic energy of flowing water but dam building processes harm ecosystems.

Alternative energy technologies are technologies that use the renewable energy sources like wind, sun and water to produce energy. These technologies range from solar power, wind power, hydroelectricity, biomass and biofuels. The biggest benefits are that these technologies use renewable resources that are naturally replenished (In contrast, fossil fuels are finite resources) and that they produce green energy and don't harm the environment. Disadvantage is that these renewable resources are unpredictable.