The United States gets 81% of its total energy from oil, coal, and natural gas, all of which are fossil fuels. We depend on those fuels to heat our homes, run our vehicles, power industry and manufacturing, and provide us with electricity. Eventually, the degree to which we depend on fossil fuels will have to decline as the planet’s known supplies diminish, the difficulty and cost of tapping remaining reserves increase, and the effect of their continued use on our planet grows more critical. But shifting to new energy sources will take time. In the meantime, how do we use fossil fuels in the most efficient and environmentally responsible way possible?
Understanding EfficiencyLearn the significance of energy efficiency
The Promise of Better LightingEnergy savings through lighting technology
Our Energy SystemA visualization of all our energy sources
- Heating Degree Days
A value representing the amount of fuel required for building heating, calculated by summing the difference of each day's average temperature below 65 degrees Fahrenheit.
Search the National Academies Press website by selecting one of these related terms.
- America’s Energy Future: Technology and Transformation (2009)
- Energy Research at DOE: Was It Worth It? Energy Efficiency and Fossil Energy Research 1978 to 2000 (2001)
- Vision 21: Fossil Fuel Options for the Future (2000)
- Review of DOE’s Vision 21 Research and Development Program, Phase 1 (2003)