There are two kinds of energy in our life. They are renewable and non-renewable sources of energy. The non-renewable energy sources include oil,coal,natural gas,... The renewable energy sources include wind, solar, biogas, hydro,... Therefore, we should use more renewable energy than non-renewable ones in the future, because the non-renewable energy sources produce a lot of carbon dioxide. That's bad for the environment, and these energy sources are going to run out soon. The renewable energy sources are abundant, cheap, clean and they're eco-friendly. They will last forever.