You've probably seen calculators that have solar cells -- calculators that never need batteries, and in some cases don't even have an off button. As long as you have enough light, they seem to work forever. There are solar cell arrays on satellites, where they are used to power the electrical systems.

The solar cells that you see on calculators and satellites are photovoltaic cells or modules (modules are simply a group of cells electrically connected and packaged in one frame). Photovoltaics, as the word implies (photo = light, voltaic = electricity), convert sunlight directly into electricity.

Photovoltaic (PV) cells are made of special materials called semiconductors such as silicon, which is currently the most commonly used. Basically, when light strikes the cell, a certain portion of it is absorbed within the semiconductor material. This means that the energy of the absorbed light is transferred to the semiconductor. The energy knocks electrons loose, allowing them to flow freely. PV cells also all have one or more electric fields that act to force electrons freed by light absorption to flow in a certain direction. This flow of electrons is a current, and by placing metal contacts on the top and bottom of the PV cell, we can draw that current off to use externally.

Solar cells alone cannot produce usable power. They need to be interconnected with other system components that ultimately conduct a specific electrical demand, or "load".

Photovoltaic systems can either be stand-alone or grid-connected. The main difference between these two basic types of systems is that for grid-connected systems, the PV system produces power in parallel with the electrical utility. It can feed power back into the utility grid if the onsite load does not use all of the PV system's output.

When the sun is shining, the direct current (DC) electricity from the PV modules is converted to alternating current (AC) by the power of an electronic inverter, and then fed directly into the site power distribution system where it supplies electric power. Any excess solar power is exported to the utility power grid and any shortfall is made up with electricity supplied by the grid. During non-sun hours, the site is supplied by utility power alone.

Hedge against Rising Electricity Prices

Solar electric systems are in many cases economically superior to conventional power systems. The operating costs are low because solar electricity needs very little maintenance, very few spare parts, and no fuel.

Non-Polluting

Solar electric systems release zero emissions into the atmosphere. Many of the traditional forms of electrical generation release carbon dioxide, nitrogen oxide, sulfur dioxide and mercury, which are known to contribute to global warming, acid rain and smog.

Reliable and Low Maintenance

You can concentrate on your core business. Solar electricity is fully automatic and therefore suitable for unmanned operation. There are no moving parts, so the system has a very long lifetime, and it is virtually maintenance-free. The quality of the power supplied is excellent, and there are very few variations, if any.

Shorter Payback & Good Return On Investment (ROI)

Solar is a low-risk, high-return investment. No matter what size system you buy, or what percentage of your electric usage you offset, your, payback period will be relatively the same. It is all a matter of how much you can invest to hedge against rising energy costs. Once your system is "paid back," you have $0 invested in your system, and a percentage of your electricity bill eliminated for decades.

Become A Sustainable, "Green" Business

Being a "green" business can, not only reduce your operating costs, but can be a great source of public relations and a good marketing tool. Studies have shown that the general public responds positively to businesses that implement energy-conscious technologies, even among audiences that have little understanding of how those technologies actually work.