This lesson has been focused on understanding energy use in Pennsylvania and the United States, including basic energy vocabulary (such as BTUs and watts); data sources for energy consumption by state; and Sankey diagrams for visualizing energy flows through a state or national energy economy. Apart from the United States being a major energy producer and consumer, we saw the following things from comparing Sankey diagrams and reviewing energy data from the U.S. government:
- The United States as a whole is heavily dependent on fossil energy (coal, oil and natural gas) for virtually every aspect of economic activity, including fueling our cars and powering homes and businesses.
- Some segments of the economy are more heavily invested in certain energy sources. Transportation in the United States, for example, is heavily dependent on oil while the power generation sector uses hardly any oil.
- While the United States as a whole relies heavily on fossil energy, this is not true of all states individually. Washington, for example, uses a lot of hydroelectricity and very little coal or natural gas.
- Pennsylvania’s mix of energy resources is very close to that of the United States as a whole.
The energy choices that we have made have been driven largely by economics, convenience and available technology. Coal dominated electric power production for so many years because it was inexpensive to mine, very dense in energy content and easy to transport and store. Transportation still relies primarily on petroleum for many of those same reasons. While the price of oil and gasoline fluctuates (sometimes wildly), petroleum-based fuels can be easily moved around and have a high energy content. Major changes in energy use can happen, but are easier to achieve in some areas of the economy than others. Natural gas has easily equaled coal in use for power generation within the span of a few short years, because of the emergence of cheap natural gas for fuel and the ability to use existing power lines to move gas-fired electricity instead of coal-fired electricity. Replacing oil completely in our nation’s energy system is a challenge because it would require technological change on a much larger scale – not only would everyone in the country need to replace their cars at great cost, but new delivery and retailing systems would be needed.