Solar Wonders, ©2007 Florida Solar Energy Center 1 Why Use Solar Energy? A modern day fable about...

Solar Wonders, ©2007 Florida Solar Energy Center

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Why Use Solar Energy?

A modern day fable about photovoltaics


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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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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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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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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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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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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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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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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.


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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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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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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?


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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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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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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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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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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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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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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 oil-

fired 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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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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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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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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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.


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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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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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A 10-kW system can help everyone

Then you learn that a 10-kW, battery-equipped 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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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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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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