Energy - Environmental Science - page 316

Figure 13-34 Global
solutions: solar cells used
to provide electricity for a re-
mote village in Niger, Africa.

T rade-Offs

used in solar cells can be made into paper-thin rigid or
flexible sheets that can incorporated into traditional-
looking roofing materials (Figure 13-33, right). Glass
walls and windows of buildings can also have built-in
solar cells.
Easily expandable banks of solar cells could
be used in developing countries to provide electricity
for the 1.7 billion people in rural villages who now
lack it (Figure 13-34). With financing from the World
Bank, India (the world's largest market for solar cells)
is installing solar-cell systems in 38,000 villages.
Zimbabwe is bringing solar electricity to 2,500 vil-
lages, mostly because they are located long distances
from power grids.
Figure 13-35 lists the advantages and disad-
vantages of solar cells. Currently, costs of producing
electricity from solar cells are high. In the future, they
will likely drop thanks to mass production and new
designs.
Currently, solar cells supply only 0.05% of the
world's electricity. With increased government and
private research and development, plus greater gov-
ernment tax breaks and other subsidies, they could
provide one-fourth of the world's electricity by 2040. If
these projections prove correct, the production, sale,
and installation of solar cells could become one of the
world's largest and fastest-growing businesses.

Solar Cells

Advantages

Disadvantages

Fairly high net
energy

Need access to
sun

Work on cloudy
days

Low efficiency

Quick installation

Need electricity
storage system or
backup

Easily expanded
or moved

No CO 2
emissions

High land use
(solar-cell power
plants) could
disrupt desert
areas

Low
environmental
impact

Last 20-40 years

Low land use (if
on roof or built
into walls or
windows)

High costs
(but should be
competitive in 5-15
years)

Reduces
dependence on
fossil fuels

DC current must
be converted to AC

x

Figure 13-35 Trade-offs: advantages and disadvantages of
using solar cells to produce electricity. Critical thinking: pick the
single advantage and the single disadvantage that you think
are the most important.

H OW W OULD Y OU V OTE ? Should we greatly increase our
dependence on solar cells for producing electricity? Cast your
vote online at http://biology.brookscole.com/miller11.