Energy is one of the most fundamental parts of our universe. We use energy to do work. Energy lights our cities. Energy powers our vehicles, trains, planes and rockets. Energy warms our homes, cooks our food, plays our music, gives us pictures on television. Energy powers machinery in factories and tractors on a farm.
Solar power, that's obvious, but the energy in coal originally came from the Sun too. Prehistoric plants stored the Sun's energy in their leaves, and when they died and eventually formed coal seams, that energy was still there. So when we burn coal (or any fossil fuel), we're releasing chemical energy that was stored in plants millions of years ago.
There are many forms of renewable energy . Most of these renewable energies depend in one way or another on sunlight. Wind and hydroelectric power are the direct result of differential heating of the Earth's surface which leads to air moving about (wind) and precipitation forming as the air is lifted.