Solar Electricity for Your Home
Solar Cells, Solar Electric Panels, Solar Energy from Photovoltaics

Solar Energy Facts

• The Earth receives as much energy from sunlight in 20 days as is believed to be stored in the Earth's entire reserves of coal, oil and natural gas.
• Some 2,000 years ago the Greeks used mirrors to focus the sun's rays on Roman ships, causing them to catch fire.
• There are presently three main types of solar power system: solar buildings, solar thermal concentration systems and photovoltaic cells. The latter were first developed for the United States' Space Programme.
• The term photovoltaic comes from the greek "phos" which means light and "volt", from the scientists Alessandro Volta. In other words, photovoltaic literally means "light-electricity".
• With today's technology, houses with passive solar design and efficient insulation can save as much as ninety nine per cent of energy used for space heating and cooling.
• Each year the sun delivers to the Earth enough free energy to light twelve million 100 Watt light bulbs all at the same time

Earthsafe: http://www.shell.com/solar Other Sources of Imformation: www.flaseaef.org www.fsec.ucf.edu www.flaseia.org www.shell.com/solar

Generating electricity directly from light

Solar cells are elegantly simple, made from special materials that are neither insulators (like plastics) nor conductors of electricity (like copper wire). When they are exposed to light and absorb photons (particles of light and other forms of electromagnetic radiation), these materials - called "semi-conductors" - allow an electrical current to be generated.

Photons contain various amounts of energy depending on the different wavelengths of the solar spectrum. This energy level determines what happens when photons strikes a photovoltaic cell, where they will either be absorbed, reflected or pass right through. Some of the absorbed photons generate electricity, others generate heat, and some never reach the external circuit.

Why do electrons move about?

The electrons in a semiconductor material live in a range of defined energy levels, each one known as a band.

The conduction band is partially filled with electrons, creating a negative charge.

The valence band has areas where electrons are missing - known as holes - equivalent to a positive charge.

In the absence of light, the positive and negative charges balance each other out. But when light energy in the form of protons strikes the semiconductor material, electrons are dislodged and the equilibrium is disturbed.

This causes electrons to move down an external circuit in the form of light-generated electricity: a phenomenon which is called the photovoltaic effect.

How much electricity is generated?

Around fifteen per cent of the energy of sunlight can be used to produce electricity using photovoltaic solar technology.

The individual solar cell's size determines the amount of current and power it is capable of producing - at most some 0.5 Volts (V). In order to generate a significant amount of electricity, several solar cells are assembled into modules.

Certain kinds of cells, such as those made from thin films, can be made directly into modules without needing to make separate cells first. Generally constructed to give an output somewhere between twenty W and 100 W, these modules can themselves be connected together to make arrays that could potentially supply several megawatts of power.

What are the different types of solar cells?

Solar cells can be made of different semiconductor materials. Each solar cell also consists of an electrical contact with the semiconductor that carries the electrons away from the solar cell and into the electrical circuit where they can, for instance, power a light bulb or charge a battery.

The whole cell is then encapsulated in a transparent cover that provides environmental protection and contains an anti-reflection coating to make sure that as little light as possible is reflected away from the cells.

The different types of solar cells are:

• Crystalline silicon solar cells
• Thin film solar cells
• Non-silicon compound thin film solar cells
• Nano-crystalline solar cells
• Fullerene solar cells

The ProChargerª line of solar modules makes it easier than ever to enjoy the many benefits of using solar energy. Solar is the clean, quiet way to generate power for many of your electrical needs. Almost anywhere that utility-grid power is not readily available, solar electricity can be your most practical and dependable power source.

ProCharger electrical systems can be setup to give you all the power you need, year around, including enough power to take care of anticipated sunless periods. Should you ever need more electricity, modular design makes it easy to expand your system. Also, Procharger modules are compatible with other types of generators to achieve complete energy solutions.

ProChargers bring ease and convenience to many popular solar uses.

Recreational Vehicles

ProChargers give RV owners independence. There's independence from the fuel, fumes, and noise of motor generators. And there's the independence from having to stay where there are electrical hookups. Whatever your need, from battery maintenance, to power for all of your appliances and accessories, ProChargers can handle it.

Boats

Solar electricity is the natural way to generate power for all or part of your boat's onboard electrical needs. Systems can be configured to power emergency-communications, lights, instrumentation, navigation equipment, and even refrigerators. ProChargers are warranted to standup to even the hardest marine environments and continue to perform efficiently.

Remote homes and cabins

The pleasure of a remote home or cabin is even greater when you are sure of year after year of trouble-free electrical power, with practically no maintenance needed. Dependable ProCharger systems operate silently, burn no fuel, and create no waste. Modular design lets you expand a system easily if your electrical needs grow.