Some 99% of the energy used to heat the earth and all of our buildings
comes directly from the sun. Solar energy helps recycle the carbon,
oxygen and water, and other chemicals we and other organisms need
to stay alive and healthy. This direct input of solar energy also
produces several forms of renewable energy: wind, falling and flowing
water (hydropower), and biomass (solar energy converted to chemical
energy stored in chemical bonds of organic compounds in trees and
other plants).
The remaining 1 %, the portion we generate to supplement the solar
input, is commercial energy sold in the marketplace. Most commercial
energy comes from extracting and burning mineral resources obtained
from the earth’s crust, primarily non-renewable fossil fuels.
How should we evaluate energy resources?
The types of energy we use and how we use them are major factors determining
our quality of life and our harmful environmental effects. Our current
dependence on non-renewable fossil fuel is the primary cause of air
and water pollution, land disruption, and projected global warming.
Moreover, affordable oil, the most widely used energy resource in
developing countries, will probably be depleted within 40-80 years
and will need to be replaced by other energy resources.
What is out best immediate energy option?
The general consensus is to cut out unnecessary energy waste by improving
energy efficiency. What is our next best energy option? There is a
disagreement about that. Some say we should get much more of the energy
we need from the sun, wind, flowing water, biomass, heat stored in
the earth’s interior and hydrogen gas by making the transition
to a renewable energy or solar age. Others say we should burn more
coal and synthetic liquid and gaseous fuels made from coal. Some believe
natural gas is the answer, at least as a transition fuel to a new
solar age built around improved energy efficiency and renewable energy.
Others think nuclear power is the answer.
Experience shows that it usually takes at least 50 years and huge
investments to phase in new energy alternatives, with the exception
of nuclear power, which after almost 50 years still provides only
a small proportion of the world’s commercial energy. Thus we
must plan for and begin the shift to a new mix of energy resources
now.
To do so involves answering the following questions for each energy
alternative:
How much of the energy source will be available in the near future
(the next 15 years), intermediate future (the next 30 years), and
for the long term (the next 50 years)?
What
is this source’s net energy yield?
How
much will it cost to develop, phase in, and use this energy resource?
How
will extracting, transporting, and using the energy resource affect
the environment?
What
will using this energy source do to help sustain the earth for us,
for future generations, and the others species living on the planet?
