Saving energy helps the environment in a number of ways, from slowing down the exploration for future energy supplies to reducing the amount of emissions that come from the operation of power plants. The more households there are actively conserving energy, the greater the cumulative benefits for the global environment.
Coal-fired power plants remain one of the most common sources of electricity in the United States. While technology has made the emissions cleaner than in past decades, particularly with regard to sulfur content, there is no way to keep carbon dioxide and some of the particulate matter from entering the atmosphere. The less energy that people use, the less coal needs to burn in those plants, and fewer pollutants enter the air.
Reducing the amount of light usage benefits the environment in a number of ways. Not only does light bring glare to the sky at night, but it represents a significant amount of energy that is consumed unnecessarily. In addition to the reduction in the use of electricity, there are also fewer light bulbs used up and ready to discard into landfills.
Cutting the amount of natural gas that goes into utility consumption cuts down on the need to try alternative exploration methods that have a potentially negative effect on the environment, such as fracking.