Why Use Solar Energy?
A modern day
fable about
photovoltaics
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Solar Wonders, ©2007 Florida Solar Energy Center
Solar energy is our planet’s
fundamental energy source
We all know that solar energy is the
fundamental energy source for the planet.
It’s the source of the light and heat that
allows life to survive and even flourish on
the Earth. It is also the main determinant
of climate around the globe, creating
winds, currents, temperature regimes and
seasons.
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Solar Wonders, ©2007 Florida Solar Energy Center
People often ignore the power of the sun
So we know, whether consciously or
not, that we live on a solar-powered
planet. Yet, rather than working with
this most-powerful of energy
sources, people frequently tend not
only to ignore the sun’s energy
potential but also to work against it.
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Solar Wonders, ©2007 Florida Solar Energy Center
Relatively few people use solar energy
For example, in Florida, there are no coal
resources, no rapidly running rivers,
almost no oil resources and very little in
the way of natural gas. There is, however,
ready access to abundant amounts of solar
energy almost every day of the year. Yet
only about 5 percent of the state’s
households use solar energy to heat
water. Instead, almost all of them use
electricity for that purpose – electricity
that was generated mostly by coal mined a
half a continent away.
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Solar Wonders, ©2007 Florida Solar Energy Center
Why not use solar in office buildings?
And another example: most office
buildings are occupied and productive
during the day, when maximum amounts of
daylight are available. Yet in most cases,
the largest expenditure for operating
energy costs in these buildings is for
electricity to power electrical lighting and
the air conditioning needed to remove the
heat these lights produce.
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Solar Wonders, ©2007 Florida Solar Energy Center
Is this logical?
In both cases, one simply must ask,
“What’s wrong with this picture?” And the
answer is, “It’s simply not logical.”
To know if an energy picture is logical, we
first need to answer the essential
question: “What are our energy needs?”
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Solar Wonders, ©2007 Florida Solar Energy Center
Creating an energy picture
Since each country and state has its own
geographic, geologic, demographic,
political, social and economic profiles, the
answer to that question will be different
in each case. So let us create our own
country to talk about – a hypothetical one
– for which we can construct a logical
energy picture based on the answers to
the preceding questions
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Solar Wonders, ©2007 Florida Solar Energy Center
A make-believe place called Isle de Soleil
Let’s create an island nation called Isle du
Soleil. The principal island covers
approximately 200 square miles, with a
couple of smaller islands nearby. The
country’s geology comprises an extinct
volcano in the center of the main island;
once tree-covered, the highlands have
been clear cut – no forests remain. The
rest of the land is moderately fertile
sandy loam.
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Solar Wonders, ©2007 Florida Solar Energy Center
Most Isle de Soleil energy comes from oil
Isle du Soleil is located quite near the
equator at between 12 and 14 degrees
latitude. It has access to lots of solar
energy; even in winter. However, most of
the energy used in the country comes
from oil, which is imported from North
America and the Middle East. The oil is
burned to generate electricity at four
main power stations located in the
country’s widely separated two main
cities.
Solar Wonders, ©2007 Florida Solar Energy Center
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The country has two main cities
Nearly half the people in Isle du Soleil live
in one of the two principal cities. Both
cities are attractive tourist locations, and
about 30% of the residents work in that
industry. Another 25% work in
government. The rest work in a variety of
construction, small manufacturing, trade
and business occupations. About 10% of
the available work force is unemployed.
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Solar Wonders, ©2007 Florida Solar Energy Center
Main industry is agriculture
Outside the two main cities, the majority
of Isle du Soleilers are involved in
agriculture, ranging from very large fruit
and bean operations all the way down to
what we in the U.S. call “truck farms,” –
small, usually family-owned acreages on
which the family grows produce for sale
locally.
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Solar Wonders, ©2007 Florida Solar Energy Center
A pretty picture
Isle du Soleil has had political
troubles in the past but now is in
a period of long-term stability.
Education is free, and literacy
rates are rising. Infant mortality
rates are falling.
Looks like a pretty picture,
doesn’t it?
Solar Wonders, ©2007 Florida Solar Energy Center
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But there are some problems . . .
But if you’re a smart energy planner, you
might see some problems in this picture.
Isle du Soleil imports 70% of its food and
virtually all of its oil resources. The
country’s cost of living is going up, as are
unemployment rates. More and more
people are leaving the agricultural sector
and moving to the big cities, which can
offer only low-paying service-sector jobs.
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Solar Wonders, ©2007 Florida Solar Energy Center
There are severe air pollution problems
As the cities grow in population, air
pollution is becoming a problem. Rates of
asthma in young people are nearly doubling
each year. You hear whispers from the
tourist industry that the cities are
becoming less attractive to potential
visitors because of the air quality. And
the country’s major trading partners are
beginning to pressure your government to
come into line with global warming policies.
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Solar Wonders, ©2007 Florida Solar Energy Center
Energy is the cause of the problems
You are a very smart energy planner. You
look beyond the effects of these
problems to their cause. And you realize
that the root cause is energy – or, more
accurately, the lack of it.
Why are people leaving agriculture and
moving to the cities?
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Solar Wonders, ©2007 Florida Solar Energy Center
Rural residents need energy to survive
In most cases, it’s because they lack
access to electrical energy. That means no
pumping power for irrigation and stock
watering. No power for lights at home, at
school, at church. No power for radios and
televisions. No power for crop drying. No
power for fish and poultry cleaning,
processing and refrigeration. Without
access to electrical energy, rural
residents see no way to improve their
lives, so they move to the cities.
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Solar Wonders, ©2007 Florida Solar Energy Center
Consider the energy options
You decide to work with the
government on a program to provide
electrical energy in rural areas. And
you begin to look at options for doing
that.
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Solar Wonders, ©2007 Florida Solar Energy Center
One choice is using fossil fuels
You consider the cost and time involved in
providing electricity to the rural
population using conventional, fossil-based,
centralized production and distribution.
Accomplishing your energy objective
through this option entails:
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Solar Wonders, ©2007 Florida Solar Energy Center
Fossil fuel options

Extending the electrical grid to “electrify”
all three islands. The cost is high, and there could
be a time lag of as much as 20 years.
or

Building three new, regionally dispersed oilfired generating plants. Construction costs range
are two to three times higher, and the time lag
could be 10 years.
And remember, the fuel costs are additional.
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Solar Wonders, ©2007 Florida Solar Energy Center
Consider the alternative energy options
After this analysis, you need to consider
alternative energy options to provide
energy where and when it’s needed. You do
some research to determine the site- and
process-specific energy needs of most of
the rural population and match up the
results with solar-based solutions.
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Solar Wonders, ©2007 Florida Solar Energy Center
A small PV system may do the job
You find that in many instances, a small
photovoltaic system may be the answer
for powering lights, television and radio on
family farms. Photovoltaics, you learn, are
solar cells that convert sunlight to
electricity. Depending on the amount of
power needed, the modules can be wired
together into arrays.
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Solar Wonders, ©2007 Florida Solar Energy Center
A 1-kW system can meet basic needs
For a typical small farm, an array
rated at about 1 kilowatt would
provide sufficient energy to meet
the basic electrical needs of a family
of four – to power lights, television,
radio, a small refrigerator and a
microwave oven.
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Solar Wonders, ©2007 Florida Solar Energy Center
Battery storage is important
But the sun doesn’t shine at night, and
even the paradise of Isle de Soleil has
some rainy days. You learn that regular
12-volt car batteries can store the solar
energy generated during the day for
nighttime use, but new battery
technologies are even better. In addition,
a charge controller installed between the
solar array and the battery will control
the battery state of charge, ensuring that
it will operate well for quite a long time. 23
Solar Wonders, ©2007 Florida Solar Energy Center
Equipment is available
You check for solar equipment suppliers in
Isle de Soleil, and find that there are
none. However, you cast your net a little
wider and find that several suppliers are
doing business in sister nations nearby.
There are lots of U.S. companies that can
help, too.
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Solar Wonders, ©2007 Florida Solar Energy Center
A larger system can help the whole village
Satisfied that solar is imminently “doable” for
small farms, you move on to other cases. Talking
to civic leaders in outlying villages, you learn that
many rural people are moving from the farms
because they want a better education and future
for their children. Most of the villages have
schools, but the schools, like the homes, have no
or very unreliable electricity. No electricity
means no lights, no televisions, no radios and no
computer. You see that whole villages may benefit
from a larger photovoltaic installation.
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Solar Wonders, ©2007 Florida Solar Energy Center
A 10-kW system can help everyone
Then you learn that a 10-kW, batteryequipped photovoltaic array installed at
the edge of a village can provide not only
the energy needed by the school, but also
additional electricity for the village
church, government offices and medical
clinic. It could even power a local
restaurant so that it could operate during
the evening hours, improving the town’s
social life, making it a more attractive
place to live.
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Solar Wonders, ©2007 Florida Solar Energy Center
The bottom line . . .
Solar energy can help Isle de Soleil
meet the energy needs of its people,
improve their air quality, and help
improve their standard of living.
It’s an alternative to fossil fuels
that needs to be considered.
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Solar Wonders, ©2007 Florida Solar Energy Center
Discussion Questions
• Compare and contrast the experience of
the people in Isle de Soleil to your own
community.
• Can you think of any real countries that
are similar to this example? Does this
apply to them?
• If you were the energy planner for Isle de
Soleil, what recommendations would you
make to the government?
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Solar Wonders, ©2007 Florida Solar Energy Center