Because most homes and businesses still get their energy from non-renewable fossil fuels, like natural gas, saving energy helps reduce the environmental impacts of fossil fuel extraction and burning. This means less habitat and species disturbance from mining, less air and water pollution from extraction and burning. Saving energy and using less fossil fuels also means we are not adding as many greenhouse gases to the atmosphere, which reduces the direct driver of climate change. Lastly, power plants that burn fossil fuels use a lot of freshwater (as steam) to turn turbines and make electricity. About 40% of all the water withdrawn from lakes and rivers in the U.S. is used for energy related processes. So saving energy also saves water!