What are the benefits using windmills?

windmils provide kinetic power (mechanical motion) without the cost of electricity or other energy supplies. it has been used by many civilizations as a means of doing work cheaply and without cost. it has been most recently used to generate electricity in wind farms by making wind push turbines in electric generators. it is currently a source of energy favoured by many enviromentalists and is currently undergoing somwhat of a rennaisance (that means it is becoming a more modern idea dispite being an idea with roots that go back hundreds of years).