122 Chapter 5 Community and Environmental Responsibilities
This source of energy is readily
available in certain geographic
locations, where it is collected as
steam to generate electricity. The
United States leads the world in
generating geothermal energy
from power plants in the western
states, Alaska, and Hawaii.
Advancements in technology
may lead to the ability to collect
geothermal energy in more
locations across the United States.
Energy in the
Future
The energy picture for the
future is clouded. Oil and natural
gas supplies are heavily used
and being depleted. Coal is one
fossil fuel that is still abundant,
but it presents some concerns.
Unless properly controlled, the
by-products of burning coal can add to air pollution.
Renewable sources currently account for only a small percentage
of U.S. energy supplies. Renewable sources offer promise, but there are
many challenges. Switching U.S. consumption away from fossil fuels
requires public support as well as new processes and facilities. Greater
investment in research and development is needed to make newer
energy forms more available and affordable. Historically low fossil-fuel
costs have discouraged those investments. Record-high prices for fossil
fuels increase interest in the renewable fuels.
You Can Help Conserve Energy
An important goal for everyone is to reduce the use of fossil fuels.
This goal is partly met by newer, energy-effi cient appliances, which are
designed to run on less energy. Another factor that affects energy use is
how people live with and use their appliances. The checklist shown in
5-8 will help you discover ways to conserve energy in your own home.
Using less energy can also lower utility bills.
Heating and Cooling a Home
More than half of the energy used by a household is for heating and
cooling. A whole-house approach is the only way to lower the amount
of energy used by the furnace and air conditioner. Controlling indoor
Science Connection
Generating Energy with Biomass
Wood once provided all the energy
needed for heating homes and cooking.
Today it is used in fi replaces, but this is a minor
use. Burning wood is restricted in many areas because the
smoke contains pollutants. Industries that convert wood to
paper, chemicals, and building products use wood waste to
produce their own steam and electricity.
Crops like corn and sugar are fermented to produce the
transportation fuel called ethanol. Another such fuel, biodiesel,
is made from oil extracted from soybeans. Although in limited
supply, these new types of fuel will become more available in
the future.
Solid waste is considered biomass if it is the type that
rots, such as food scraps and lawn clippings. (Trash also
contains glass, metals, and plastics, which are not biomass.)
Burning this waste generates steam and an ash by-product,
often used for roads. When the waste is placed in a landfi ll, it
releases a gas that can be converted to a fuel source.
Serving Your
Community
Develop a Web page of
energy-saving tips, devoting
separate sections to specifi c
appliances or activities. Be
sure to cite your sources
for various statistics, if any
are used. Include links to
helpful Web sites. Work with
your teacher to post the
information on your class
or school website.