Renewable energy, defined as resources that are naturally replenished, include wind, rain, sunlight, water currents and geothermal heat. Our modern day renewable energy techniques may have been introduced much earlier in time than some would think. For instance, did you realize that the first wind turbine to generate electricity was built in 1888?

History dates back watermills to 2,000 years ago and windmills to over 1,000 years ago. But back then, these machines were used for their mechanical output in jobs such as grinding grain and textile production. This was well before our discovery of modern electricity usage.