In contrast, fossil fuels like coal, oil, and natural gas are not renewable; that is, they draw on finite resources that will eventually dwindle, becoming too expensive or too environmentally damaging to retrieve.  Most renewable energy comes either directly or indirectly from the sun.   Sunlight, or solar energy, can be used directly for heating and lighting homes and other buildings, for generating electricity, and for hot water heating, solar cooling, and a variety of commercial and industrial uses.  Interested? Take our energy quiz to see how much you
know...

   The sun's heat also drives wind, and this wind energy can generate electricity through turbines. Then, the wind and heat of the sun causes water to evaporate.  When this water vapor turns into rain or snow and flows downhill into rivers or streams, its energy can be captured using hydroelectric power.  Are you ready to hook up your gym's bicycle spinner to a generator to help out your community's electric grid? This "human power" is being done now around the country...
 

    Sunlight causes plants to grow along with the rain and snow.  The organic matter that makes up those plants is known as biomass.  Biomass is used to produce electricity, transportation fuels, or chemicals.  The use of biomass for any of these purposes is called biomass energy.
Not all renewable energy resources come from the sun.  Geothermal energy taps the Earth's internal heat for a variety of uses, including electric power production, and the heating and cooling of buildings. And the energy of the ocean's tides comes from the gravitational pull of the moon and the sun upon the Earth.  In fact, ocean energy comes from a number of sources.  All these forms of energy, can be used to produce electricity.   From the National Renewable Energy Laboratory (search on "NREL.gov")

A:  When specific semi-conducting materials, like silicon, are exposed to  

      sunlight, they release small amounts of electricity.

  This process is known as the photoelectric effect.  The photoelectric effect refers to the emission, or ejection, of electrons from the surface of a metal in response to light. It is the basic physical process in which a solar electric or photovoltaic (PV) cell converts sunlight to electricity.

   Sunlight is made up of photons, or particles of solar energy.  Photons contain various amounts of energy, corresponding to the different wavelengths of the solar spectrum. When photons strike a PV cell, they may be reflected or absorbed, or they may pass right through. Only the absorbed photons generate electricity.  When this happens, the energy of the photon is transferred to an electron in an atom of the PV cell (which is actually a semiconductor).

   With its newfound energy, the electron escapes from its normal position in an atom of the semiconductor material and becomes part of the current in an electrical circuit.  By leaving its position, the electron causes a hole to form.  Special electrical properties of the PV cell -- a built-in electric field -- provide the voltage needed to drive the current through an external load (such as a light bulb).

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FAQ #3:  What is meant by "photovoltaics," or "PV"?*
A:  Photovoltaics can literally be translated as "light-electricity."

   The word itself helps to explain how photovoltaic (PV) or solar electric technologies work. First used in about 1890, the word has two parts: photo, a stem derived from the Greek phos, which means light, and volt, a measurement unit named for Alessandro Volta (1745-1827), a pioneer in the study of electricity. So, . And that's just what photovoltaic materials and devices do; they convert light energy to electricity, as Edmond Becquerel and others discovered in the 18th Century.  (From the U.S. Dept. of Energy web site (search on "eere.energy.gov")

~ Read up on more facets of solar energy... see John Perlin's book,

 From Space to Earth-The Story of Solar Electricity (shown here).

FAQ #4:  What are some "basics" about using solar energy?*

A:  Solar photovoltaic (PV) cells are small, square-shaped semiconductors manufactured in thin film layers from silicon and other conductive materials.

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 FAQ #5: What is the "Million Solar Roofs" Program?*

A:  President Bill Clinton began the "Million Solar Roofs" program in 1997 and it has supported the installation of thousands

of solar systems. 

   The Million Solar Roofs Initiative is a federal public-private partnership, aimed at overcoming barriers to market entry for selected solar technologies.  The goal of the initiative is practical and market-driven: to facilitate the sale and installation of one million "solar roofs" by 2010.  Eligible technologies include photovoltaics (PV), solar water heating, transpired solar collectors, solar space heating and cooling and pool heating.  In California we have the "26 million roof" program...  Here's an apt quote for our current environmental situation, by President Clinton...

   "The science is clear and compelling: We humans are changing the global climate.  Concentrations of greenhouse gases in the atmosphere are at their highest levels in more than 200,000 years and climbing sharply.  If the trend is not changed, scientists expect the seas to rise two feet or more over the next century.  In America, that means 9,000 square miles of Florida, Louisiana, and other span-coastal areas will be flooded.

We will work with businesses and communities to use the sun's energy to reduce our reliance on fossil fuels by installing solar panels on one million more roofs around our nation by 2010.  Capturing the sun's warmth can help us to turn down the earth's temperature."       -- Former President Bill Clinton, 1997

    Million Solar Roofs (MSR) is helping increase the market for solar energy. Now it's called 10 Million Roofs. At the same time, the Initiative is offering consumers an affordable, clean-energy option, creating new U.S. high-technology jobs, and playing an important role in reducing emissions.   The MSR web site (http://www.millionsolarroofs.org) provides information and resources for those who want to participate in the partnership and for those who want to learn about how others are participating.  For partnerships the site provides seminar and workshop listing, success stories, logos, graphics, and other outreach tools for the grassroots promotion of solar energy.  The MSR partnerships are administered through the U.S. Department of Energy's Regional Offices. 

 (For info., search on "Solar Energy Technologies Program U.S. DOE" and "million solar roofs")

Photo Hap Haven, from Solar Energy Technologies Program

- U.S. DoE's Million Solar Roofs

FAQ #6:  What are the components of a photovoltaic (PV) system?*
 

A:  A PV system is made up of different components.

   These include solar modules or solar panels; one or more batteries; a charge controller for a stand-alone system; an inverter for a utility-grid-connected system; wiring; and mounting hardware or a framework.

FAQ #7:  What are the 4 main types of solar energy technology?*
 

A:  The four main types of solar energy technologies are:

The basic PV module (interconnected, enclosed panel of PV cells) has no moving parts and can typically last more than 20 years.  The amount of time depends on the quality of the manufacturing process.  The best way to ensure and extend the life and effectiveness of your PV system is by having it installed and maintained properly.

   Experience has shown that most problems occur because of poor or sloppy system installation.  Failed connections, insufficient wire size, components not rated for dc application, and so on, are the main culprits.  The next most common cause of problems is the failure of the electronic parts like the controller, inverter, and protection components. 

Batteries fail quickly if they're used outside their operating specification.  For most applications (uses), batteries should be fully recharged shortly after use.  In many PV systems, batteries are discharged AND recharged slowly, perhaps over a period of days or weeks.  Some batteries quickly fail under these conditions.  Be sure the batteries specified for your system are appropriate for the application.

Building and maintaining a pool, however, also means relatively high costs added to your household's budget. There are several ways that you can reduce operating and maintenance costs, lower water consumption, and conserve heat if you heat your pool.

Many people heat their pools to extend the swimming season and/or to keep it at a temperature that they are personally comfortable with. This lets them enjoy the full value from their pool.  Solar pool heaters are an option to heat the pool with "clean" energy from the sun, and can reduce heating costs. See the web site for more information and a fact sheet.  From the U.S. Dept. of Energy web site (search for "eere.energy.gov")

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FAQ #10:  What are some applications for solar?*

 
A:  Photovoltaic systems are especially well suited to locations where accessing an electrical grid is either not feasible or expensive.

In many such locations, solar (or photovoltaic technology) is the least-cost option for meeting  energy needs.  Photovoltaic systems have proven to be a reliable source of power in an ever-growing number of applications.  Lighting is one common use for these systems. 

Thanks to U.S. National Renewable Energy Laboratories (NREL) for photo. 
Notice the car getting its "fuel" via a wire from solar panels...

Cost-effective applications of lighting powered by photovoltaics include small garden lights, street lights, lighting for recreational areas, highway signs, warning signs and signals, and for businesses and homes both in the developed and developing world.

  Photovoltaic systems are ideal and commonly used for water pumping because water can be pumped into a storage tank during daylight hours, then distributed by gravity whenever it is needed. Photovoltaic systems commonly pump water for livestock watering tanks, and in the developing world, entire village water supplies are powered by photovoltaics.  Other uses include remote monitoring, refrigeration, and energy for small commercial ventures.  Any power need can be met with photovoltaics, although some are more cost-effective than others.

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FAQ #11:  Why should I use PV (photovoltaics)?*
 

 A:  There are many reasons for using PV: You should use a PV system

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FAQ #12:  How Serious is Global Warming?*

  By signing up for green power you help protect the environment for us and for our children.  A lot of U.S. electricity is generated by coal and other petroleum-based fuel, and emissions from these fossil fuels is strong suspect for just one of the causes of global warming.  [Segue to Solar note: Not to mention horrible pollution that has penetrated our air, our water, our land, our lungs.]  This is creating a "greenhouse" effect, raising the temperature of the planet, causing extreme weather, spreading infectious diseases, raising the sea level, and increasing extinctions of entire species. 

R   Unless we begin a substantial shift now from fossil fuels to renewable energy sources, like solar and wind power, the consequences could be catastrophic.   -- For more information search on "earthdayla.org". 

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FAQ #12:  What can consumers do to reduce global warming?*

A:  Here are some things you can do in your own life to reduce

     global warming and fight air pollution. 

   Turn to Green Power:   Any homeowner or business can arrange electricity from non-polluting renewable sources like solar and wind power (just google "solar power" or "green power").

  Be energy efficient around the house:  Using compact fluorescent light bulbs is only one of many things you can do around the house to save energy, reduce global warming and clean the air.  Turn out lights when you leave a room.  Install an insulation blanket around your water heater (available at your hardware store).   And when you buy new appliances look for the Energy Star seal and efficiency rating. 

   Curb your car, every now and then: 

Cars are the largest source of air pollution and global warming gases in Los Angeles.  So, use a bus, take a bike, or walk, whenever you can.  Carpool to work with a friend.  And when you buy a new car, get one with high gas mileage and low smog emissions.  When you are going to run errands, reduce driving by combining trips.  And keep your tires properly inflated (like the President of the United States - President Obama - even advised us!), and your car tuned for the best gas mileage.

 Recycling is not enough:   In addition to recycling, we need to think about what we buy before we buy it.  So buy toilet paper, paper towels, and other products made from post-consumer recycled materials, and buy organically grown food (food grown without toxic pesticides) like organic milk, produce, eggs, and pasta sauce.  After all, almost everything takes raw materials and energy to produce, and causes some pollution.  So conserve energy, save your money, and let's leave enough for the future inhabitants of earth...