Why would the use of alternative sources of energy be beneficial to the earth and its people?

There are several reasons why the use of alternative sources of energy would be beneficial to the Earth and its people, but the main reason is that fossil fuels will run out soon. 

Alternative energy sources would allow for sustainability and less pollution on Earth. If we can use solar, wind, hydroelectric, biofuel, etc., then we can actually have a sustainable form of energy. None of these forms of energy require harm to the environment to tap into, unlike oil which requires drilling, and its not in infinite supply. Traditional power plants use either nuclear or wood-pellet energy. With nuclear, the waste left behind is extremely toxic and requires underground storage, and with wood-pellet, an immense amount of carbon is released into the atmosphere. So basically, alternative energy sources would benefit humans greatly by making our energy sustainable and preserving our climate and environment.