Energy - Environmental Science - page 285

13

Nonrenewable
Energy

Renewable
Energy

Energy

CASE STUDY
The Coming Energy-Efficiency
and Renewable-Energy
Revolution

water with the condensation from the cooling pipes
used for irrigation.
A small (but growing) number of people in devel-
oped and developing countries get their electricity
from solar cells that convert sunlight directly into elec-
tricity. These devices can be attached like shingles to a
roof, used as roofing, or applied to window glass as a
coating. Solar-cell prices are high but falling.
According to many scientists and executives of oil
and automobile companies, we are in the beginning
stages of a hydrogen revolution to be phased in during
this century as the Age of Oil begins winding down.
Because little hydrogen gas (H 2 ) is readily available,
we must use another energy resource to produce it
from water or various organic compounds such as
methane. We could do so by passing electricity pro-
duced by renewable energy from wind turbines, hy-
droelectric power plants, solar cells, biomass, and ge-
othermal energy from the earth's interior through wa-
ter to make H 2 gas. Energy-efficient fuel cells could
produce electricity by combining hydrogen and oxy-
gen gas to run cars and appliances, heat water, and
heat and cool buildings.
Burning hydrogen in a fuel cell by combining it
with oxygen produces water vapor and no carbon
dioxide. Shifting to hydrogen as our primary energy
source would therefore eliminate most air pollution
and greatly slow global warming—as long as the hy-
drogen is produced
from water and not car-
bon-containing fossil fu-
els and the nuclear fuel
cycle that emit the
greenhouse gas CO 2
into the atmosphere.

Energy analyst Amory Lovins built a large, solar-
heated, superinsulated, partially earth-sheltered home
and office in Snowmass, Colorado (Figure 13-1),
which experiences severely cold winter temperatures.
The same structure also houses the research cen-
ter for the Rocky Mountain Institute. This
office-home gets 99% of its space and water heating
and 95% of its daytime lighting from the sun, and
uses one-tenth the usual amount of electricity for a
structure of its size.
With today's superinsulating windows, a house
can have many windows without experiencing much
heat loss in cold weather or heat gain in hot weather.
Thinner insulation now being developed will allow
roofs and walls to be protected far better than in to-
day's best superinsulated houses.
Some of today's green and smart buildings have
lights run by sensors that dim when its sunny and
brighten when its cloudy and air conditioners that
shut off when a window is open. A new building at
the Natural Energy Lab of Hawaii uses no energy
from the electricity grid. It is cooled with piped in sea-

Figure 13-1 The Rocky
Mountain Institute in Colorado.
This facility is a home and
a center for the study of en-
ergy efficiency and sustain-
able use of energy and other
resources. It is also an exam-
ple of energy-efficient passive
solar design.