Powering the Planet

Despite modern society's heavy dependence
on fossil fuels for energy, most people are
aware that the supply of these fuels is finite. As
oil and other fossil fuels become more costly
and difficult to find, researchers are looking
at alternative energy sources, including solar,
wind, and even nuclear power. But which
substitute—if any—is the right one?

Solar Solar panels catch energy directly from the sun
and convert it into electricity. One of the world's
largest solar power stations is in the Indian state
of Tamil Nadu, where more than 2.5 million solar
panels have the capacity to generate enough
power for 750,000 people. But unlike the burning
of fossil fuels, the process used to create all that
solar energy produces no emissions.

Today, however, solar power provides less than
2 percent of the world's energy, primarily because
the cost of the panels is still very high. But price
is only one issue. Clouds and darkness also cause
solar panels to produce less energy. This requires
that additional power sources (such as batteries)
be available.

Some scientists think the solution to this
problem can be found in space, which is the
ideal place to gather energy from the sun. With
no clouds and no nighttime, a space-based solar
power station could operate constantly. These
stations would send the power back to Earth,
which could then be turned into electricity for
consumption. Advocates of solar space stations
say this technology would initially require a
lot of money, but eventually it could provide
continuous, clean energy that would be cheaper
than other fuels. Also, unlike other energy
sources, solar power from space would last as
long as the sun shines, and would guarantee
everyone on Earth all the energy they need.

Wind Wind—the fastest-growing alternative energy
source—is another way of collecting energy from
the sun. Wind is caused by the sun's heat rather
than its light. Therefore, unlike solar power, wind
power works well even on cloudy days.

All over the world, incentives designed to
decrease the dependence on oil and coal have
led to a steep increase in wind-powered energy.
Today, Asia leads the world in wind power,
producing around 230,000 megawatts,1 the
equivalent of 230 large coal-powered plants.
Europe produces nearly 180,000 megawatts.
North America remains a distant third, at 105,000.

Despite its successes, some people are
protesting wind-power development, saying
the turbines2 are both noisy and ugly. Just
outside England's Lake District—a protected
national park—a dozen existing wind towers
are due to be removed. "This is a high-quality
landscape," says one local homeowner. "They
shouldn't be putting those things in here."

There are other challenges, too. If the wind
doesn't blow, the turbines are not able to
produce adequate energy. As a result, other
power sources are needed. In contrast, a strong
wind can create too much power. In cases like
this, the energy company must sell the extra
power at a much-reduced rate, which is not
good for business.
What's needed for both wind and solar is a way
to store a large energy surplus.3 However, most
systems are still decades away from making this
a reality. On the plus side, both wind and solar 1 A megawatt is a unit of power.

power enable people to generate their own
energy where they live: People can have their
own windmills or solar panels, with batteries
for calm days.

Nuclear In the 1970s, nuclear power was seen as the main
energy alternative. Nuclear power produces vast
amounts of electricity more cheaply than gas or
coal, with no carbon emissions. For a number
of years in the 1980s and '90s, however, use
of nuclear power declined due to accidents,
concerns about nuclear waste storage and
disposal, and high construction costs.

Today, times are changing. Worldwide, about
450 plants generate 11 percent of the planet's
electric power, and some countries have
invested heavily in nuclear energy. France, for
instance, gets three-quarters of its electricity
from nuclear power, the highest percentage of
any country. China has started to build one or
two new plants a year, and India has also begun
to utilize nuclear energy on a large scale.

However, there are still concerns about the
safety of nuclear power, as seen, for example, at
the Fukushima nuclear power plant in Japan.
The country had to close the nuclear reactors
at Fukushima when the plant was hit by a
tsunami and, as a consequence, began releasing
substantial amounts of radioactive materials.
Many still believe, however, that nuclear
power is one of the future's greenest energy
alternatives.

In the end, are any of these sources alone
the answer to our current energy problems?
The short answer is no, but used in some
combination—along with other power sources—
we may find ways to reduce and eventually
eliminate our dependence on fossil fuels.