Solar Panels can provide clean, renewable energy using the power of the Sun. The star the Earth revolves around is expected to last for billions of years yet, so for all intents and purposes it can be considered a renewable resource - a resource whose energy supply cannot be exhausted. In terms of solar insolation, or radiation energy received on a surface over a period of time, the Earth receives 174 petawatts (or 174 quadrillion watts) of solar energy, and of this amount about 30% is reflected back into space. Earth's worldwide power consumption is roughly 15 terawatts (or 15 trillion watts), so it is clear that the sun provides enough energy for all of our needs.
A Solar Panel generates electricity through the photovoltaic effect, which excites electrons in certain semiconductor materials. This process emits no harmful particles. A solar panel's production may contribute to environmental problems, but when compared to traditional fossil fuels the total impact of the solar panel on the environment is negligible.
(If you want to learn more about the costs as they pertain to a residential installation, check our section on solar panel cost.)
Energy generates from Solar Panels is clean, but is more expensive than traditional fossil fuels, and not as reliable. However, unlike fossil fuels, solar energy is renewable and can power humanity's needs for the indefinite future. Fortunately, the cost per watt of energy generated from solar panels is falling, due to advances in solar panel technology and economies of scale due to more widespread adoption of solar energy. In 2009, the average cost of solar energy dropped to $4.20 per watt, but some vendors...such as NanoSolar, have claimed they can generate power as low as $1/watt. Nuclear power, by constrast, produces power at about $1.60 per watt, and coal power has a typical rate of just under $2.00/watt. (A watt is equal to one joule of energy per second.)
A Solar Panel is designed to absorb only certain wavelengths along the electromagnetic spectrum, and solar panels do not operate at peak efficiency when in low-light conditions. As such, the amount of power generated from solar panels is dependent on the region where they are used, as well as the weather. Heavy cloud cover or other environmental shadowing may affect performance, and average solar insolation at night drops significantly. For this reason, a solar panel array is often used as a supplemental energy source. Many homes - for example - have on-grid installations, where solar panels provide the bulk of the home's wattage needs, but during periods of low local solar insolation, energy from the grid is used. Other installations (including dedicated off-grid installations) store energy generated by the solar panel in batteries, and are completely independent of the power grid.
Solar Panels are a growing part of the world's diverse energy solution. Solar Panels function as a good supplement to current power-generating technologies, and with advances in photovoltaic technology, solar panels are expected to power much of the world's energy needs for for the immediate and distant future. Solar power is non-polluting, renewable, easily harvested, abundant, and growing ever more inexpensive.