Photovoltaic systems (or PV systems) are solar energy systems that are able to use one or multiple solar panels for the purposes of converting light from the sun into energy and more specifically, electricity. PV systems are made up of a number of components including photovoltaic modules, electrical connections, mechanical connections, system mountings and tracking systems as well as connections to modify and regulate the output of electricity.
Because each individual solar cell will only make up a low voltage, as number of cells are normally wired together in a series, as part of the manufacturing of a laminate. This laminate will be put together inside a suitable protective enclosure that will protect the laminate from the weather. This combined unit is known as a solar panel or photovoltaic module. A number of these modules can then in turn be strung together to make a solar or photovoltaic array. Normally PV arrays will then use something called an inverter to convert the DC power produced by the solar modules over to an alternating current which is itself then able to give electricity to motors, lights and other electrical loads. Modules in a PV array are normally designed to be connected in a series so that they can reach the intended voltage. After that the individual strings should be connected up in parallel formation in order to allow the system to produce significantly more current. This current is normally measured using PTC (PVUSA) conditions and is recorded in units of Watts, Kilowatts and (for really impressive systems) megawatts.
The cost of producing photovoltaics has been significantly reduced in recent years thanks to more and more people opting to use the technology and more and more companies mass producing the components. Technological and manufacturing advances have seen costs brought down whilst energy production capabilities have increased. One figure regularly quoted for comparison purposes is that in 1996 it would have cost you $8-$10 per Watt, whilst in 2006 it would have cost you $3-$8 per Watt. New technologies that have brought about this reduction in costs include the replacement of the more expensive crystal silicon cells with the cheaper multi-crystalline silicon solar cells; in addition the technology has now improved enough that ultra-thin film silicon solar cells are now able to be made at a much lower production cost. Whilst these new forms are less efficient when it comes to converting energy in comparison with the single crystalline ‘siwafers’ they are far easier to produce and for much less money.
Lastly, the energy produced from these photo-voltaic arrays is now able to either be used directly on site in a standalone plant, or fed back into the grid at a set tariff. There is also currently a great deal of research being done into ways to efficiently store the energy on site so that it can be used later.