What's Up With Solar Energy?

Solar energy is power that comes from the sun. Solar energy can be harnessed in two different ways. One way is through photovoltaic conversion. Another way is through solar thermal conversion.

During photovoltaic conversion, solar energy is collected through panels, called solar panels. Solar panels are covered with large modules which are covered with lots of little PV cells, or photovoltaic cells. The PV cells collect the light from the sun. Once the light is inside a PV cell, there is a semiconductor made A Solar Panel Module

of a thin sheet of silicone crystal which takes in the photons from the sunlight. A photon is a particle of solar energy. Within the semiconductor, energy of the photons shifts to the electrons. This energizes the electrons. Then the electrons break out of the semiconductor to get to the silicone atoms. Then they flow into the electric current. Usually a solar cell is made of a glass protective layer, an anti-reflective coat, and electric contacts.

We use PV cell systems every day. Common tools like watches and calculators are powered with PV systems. Look at the top of a calculator. Do you see the little squares at the top? Those are lots of little PV cells. Usually PV cells don’t generate much electricity. PV cells generate about ½ a volt per square decimeter. A solar panel making fifty watts of electricity is about four decimeters by ten decimeters. What if you don’t know how much energy your appliance or machine needs? Well, the answer is easy. Find out the maximum amount of watts the appliance or machine needs and multiply that by

the number of hours each day it is averagely used. The answer is “the number you come up with” watt-hours. To explain it more, let’s say my microwave oven uses a maximum of 2000 watts and it is used ½ an hour each day. 2000 multiplied by ½ an hour equals 1000, so I need my PV system (my solar panels) to supply 1000 watt-hours for that microwave oven. Since I need to be ready for a crash or a change of appliance, I should really have my solar panels supply about 2000 watt-hours

Okay, more about a PV cell system. Most PV cells are grouped together in arrays. Second, groups of PV cells generate a DC or direct current. That is the kind of electricity made by batteries. Some appliances and other machines like microwave ovens use AC, or alternating current, so inverters are used to change the DC into an AC.

Another type of solar energy is solar thermal conversion. In this process, there are thermal conversion panels (panels that absorb heat) which are grouped together often in a dish or trough system. The solar energy is then absorbed and concentrated into a line or a point that heats a pipe filled with fluid. These systems can concentrate the intensity of sunlight up to 10,000 times of normal sunlight.

Many people use a solar heating system to heat their house. This type of system is more effective than using a PV system to heat homes or water. You can tell the difference because solar heaters can turn 60% of the sun's energy into heat whereas PV systems can only change 12% to 15%. Solar heaters are able to heat large things like pools, water, and houses. So as you can see, when it’s heating, you are better off using a solar heater.

Solar energy is a great alternative source of power. Solar panels may be expensive but in the long run they are better for two reasons. One, they lower the electricity and heating bills. Two, they are better for people and the environment because they don’t pollute the air like the burning of fossil fuels. The Nuna 3

Let’s look at this a different way to see why you should use solar energy. Even though using solar energy can be more expensive than burning fossil fuels, it is clean and sunlight is easily available. Also, you may not realize it but lots of everyday things use solar energy. Things like lights in the yard, calculators, and even cars. The Nuna 3 is a race car made by the Dutch Nuna team. It is completely powered by solar energy.

Northern Mexico has one of the best potentials for solar power in the world. Here are some examples of Mexico’s potential:

Solar "Hot Pot" Ovens
Solar ovens are really cool and cheap. Solar ovens are a great alternative to cooking over traditional wood fires. The hot pot can be left outside during daylight hours to cook many different types of food. It saves people energy, since they don't need to get wood. Other benefits are that it doesn’t have as much of an environmental impact, and it reduces the exposure of women and children to smoke.
Battery-less Flashlights
Flashlights are used sparingly in Mexico because batteries are so expensive. One alternative is a durable, long-lasting flashlight that does not use batteries. This kind of flashlight gets power just by shaking it (the LED bulb lasts a long time and they are sealed and waterproof).
Solar Water Distillers
Water is the most precious resource in the desert, and the desert makes up most of Mexico. There are no wells in communities so rainwater is collected in deposits. This rainwater is not safe to drink, and so families need to boil the water using wood fires. A solar water distiller can provide safe drinking water, so there is no longer a need to boil water. The distiller is basically a box in which water is evaporated and collected. The distiller is expected to last many years. Distillers can provide better quality water while reducing the work involved and the health and environmental impacts of burning wood.

Planners can use maps to identify the best sites for wind, solar, and hybrid renewable energy systems, and to estimate the resources available at any site where renewable applications are being considered. The National Renewable Energy Laboratory (NREL) is actively working to find and use the power available in Mexico. All of the power mappings done of Mexico can be found at Renewable Resource Assessment.

The numbers of solar energy megawatts being used is climbing fast. In 2005, 1460 megawatts (MW) were sold and installed. Germany had 57% of that number! The rest of Europe had 6%. The United States had 7% of the 1460 MW. Japan had a good 20%. The rest of the world had 10%. In 2005, the world produced 1656 MW. The Japanese producers led with 46% of that. Solar energy works well all over. Each month a one kilowatt photovoltaic system:

Stops about 105 gallons of water from being used.
Stops nobelium and sulfur dioxide from coming into the environment.
Stops 300 pounds of carbon dioxide from coming into the atmosphere.
Stops the mining of 150 pounds of coal.

As you can see, solar energy is being used around the world, and it is making a difference.

Permission to use photographs or clip art image/s of The Nuna 3, solar power collector, microwave, prism and light, solar cell, solar panel module, Earth, galvanic cell diagram, sun compared to the earth, the sun, sundial, and solar collector in field is granted under the terms of the GNU Free Documentation License from Wikipedia, the Free Encyclopedia. <http://en.wikipedia.org/wiki/Main_Page> (December and January, 2006-2007).

Flash movie created by author of this web page. Permission to use all images is granted under the terms of the GNU Free Documentation License or pictures are in the public domain from Wikipedia, the Free Encyclopedia. January-February 2007 <http://en.wikipedia.org/wiki/Main_Page>.