Chapter 14 Summary
The United States now relies on fossil fuels for over 85% of
its energy: About 40% comes from oil, and 20 to 25% each
from natural gas and coal. All the fossil fuels are nonrenewable
energy sources. Known oil and gas supplies have been seriously
depleted and may be exhausted within decades. Remaining
coal supplies are much larger, but many hazards and unsolved
environmental problems are associated with heavy reliance
on coal: acid rain, acid runoff, mine accidents and fires, stripmine
reclamation issues, and more. Technical, environmental,
and economic problems also limit the potential of other fossil
fuels—petroleum derived from oil shale or tar sand—to
become major energy sources. It seems likely that other, nonfossil
energy alternatives will be essential in the future.
