The U.S. has made great strides in creating a more sustainable energy economy thanks to the progress made in three major sectors - natural gas, energy efficiency and renewables. Sustainability is at the forefront of discussions about U.S. energy practices. You may have noticed that your home or business energy bill has grown over the last few years as electricity rates continue to increase. This has been the subject of frustration for many. Fortunately, a lot of progress has been made in making the country's energy supplies cleaner and more affordable. While certain technologies are ready for widespread use than others, there have been advances made in diverse range of industries, which are producing strong results. Bloomberg New Energy Finance recently published its 2014 Sustainable Energy in America Fact Book, which provided some important insight into the productivity being made in the U.S. The report found though the country's gross domestic product grew by 6% between 2007 and 2013, energy use fell by 5% during that time, meaning that U.S. citizens are making their power usage go further. A result of this improved productivity is a decrease in U.S. greenhouse gas emissions. The energy industry is one of the greatest contributors to air pollution, with power plants contributing roughly 40% of these emissions in the U.S. Fortunately, the measures taken in the U.S. have brought pollution down nearly 10% since 2005. So what is driving this progress in the U.S.? Bloomberg noted that it was not any one industry, but a variety of improvements that have made such strong contributions. Natural gas has emerged as an affordable alternative to energy sources like coal, and it produces half as many greenhouse gas emissions. Coupled with an increase in domestic supplies, natural gas is now more readily available and inexpensive. As a result, consumption and production levels were at all-time highs in 2013. Renewable energy has also been one of the major drivers of growth, as prices for wind turbines and solar modules have fallen significantly since 2008. As a result, more power providers have invested in sustainable electricity sources. Finally, energy efficiency has grown more popular, with energy service companies spending over $12 billion on efficiency improvements in 2012 alone. Katia Lundy is the director of marketing & communications of Plymouth Rock Energy, Woodmere, N.Y.