Top 7 Renewable Energy Resources
Larry West – Environmental Issues Guide
Many nations count on coal, oil, and natural gas to supply most of their
energy needs, but reliance on fossil fuels presents a big problem.
Fossil fuels are a finite resource. Eventually, the world will run out
of fossil fuels, or it will become too expensive to retrieve those that
remain. Fossil fuels also causes air, water, and soil pollution, and
produce greenhouse gases that contribute to global warming.
Renewable energy resources, such as wind, solar, and hydropower, offer
clean alternatives to fossil fuels. They produce little or no
pollution or greenhouse gases, and they will never run out.
-
Solar Energy The sun is our most powerful source of
energy. Sunlight, or solar energy, can be used for heating, lighting,
and cooling homes and other buildings, generating electricity, water
heating, and a variety of industrial processes. Most forms of
renewable energy come either directly or indirectly from the sun. For
example, heat from the sun causes the wind to blow, contributes to
the growth of trees and other plants that are used for biomass energy,
and plays an essential role in the cycle of evaporation and
precipitation that makes hydropower possible.
-
Wind Energy Wind is the movement of air that occurs
when warm air rises and cooler air rushes in to replace it. The
energy of the wind has been used for centuries to sail ships and
drive windmills that grind grain. Today, wind energy is captured by
wind turbines and used to generate electricity.
-
Hydropower Water flowing downstream is a powerful
force. Water is a renewable resource, constantly recharged by the
global cycle of evaporation and precipitation. The heat of the sun
causes water in lakes and oceans to evaporate and form clouds. The
water then falls back to Earth as rain or snow, and drains into
rivers and streams that flow back to the ocean. Flowing water can be
used to power water wheels that drive mechanical processes. Captured
by turbines and generators, like those housed at many dams around the
world, the energy of flowing water can be used to generate electricity.
-
Biomass Energy Biomass has been an important source
of energy ever since people first began burning wood to cook food and
warm themselves against the winter chill. Wood is still the most
common source of biomass energy, but other sources of biomass energy
include food crops, grasses, and other plants, agricultural and
forestry waste and residue, organic components from municipal and
industrial wastes, even methane gas harvested from community
landfills. Biomass can be used to produce electricity and as fuel
for transportation, or to manufacture products that would otherwise
require the use of non-renewable fossil fuels.
-
Hydrogen Hydrogen has tremendous potential as a fuel
and energy source, but the technology needed to realize that
potential is still in the early stages. Hydrogen is the most common
element on Earth – for example, water is two-thirds hydrogen
– but in nature it is always found in combination with other
elements. Once separated from other elements, hydrogen can be used
to power vehicles, replace natural gas for heating and cooking, and
to generate electricity.
-
Geothermal Energy The heat inside the Earth produces
steam and hot water that can be used to power generators and produce
electricity, or for other applications such as home heating and power
generation for industry. Geothermal energy can be drawn from deep
underground reservoirs by drilling, or from other geothermal
reservoirs closer to the surface.
-
Ocean Energy The ocean provides several forms of
renewable energy, and each one is driven by different forces. Energy
from ocean waves and tides can be harnessed to generate electricity,
and ocean thermal energy – from the heat stored in sea water
– can also be converted to electricity. Using current
technologies, most ocean energy is not cost-effective compared to
other renewable energy sources, but the ocean remains an important
potential energy source for the future.