Solar Photovoltaics Overview
Photovoltaic cells convert sunlight into electricity. Solar panels incorporate many solar cells together to work in unison while also packaging the solar cells in a durable frame. Because photovoltaic cells produce DC (direct current) power, they are not compatible with homes and buildings, which are powered by AC (alternating current). To solve this problem, the DC power produced by the solar panels runs through a specialized device called an Inverter that converts DC power to AC power.
Most Solar PV Systems are GT (grid-tied). This means that the electricity generated by the PV System is fed into the local Utility Grid via interconnection. The PV System acts as a mini-power plant.
Financially Viable - Utility Bill Savings
The greatest benefit of a Grid-Tied System is it allows 100% use of the power produced by the Solar PV System. The interconnected utility will sometimes buy back the power produced by a personally owned PV System though a Power Purchase Agreement. This has an added benefit of making a Solar PV System financially viable as a long-term investment. With federal, state and local solar incentives in some areas of the country, the electric utility bill savings will completely pay for a Solar PV System in as little as 5 years. To place the significance of this in context, a typical Solar PV Systems will last 20 to 30 years or even longer.
Ironically, Solar is most commonly associated with off-grid systems despite the fact off-grid systems make up a very small amount of total solar installations. Off-grid systems are systems in which the solar panels are used to charge batteries. The batteries then feed power to an inverter that feeds the converted AC electricity to power a small room or building.
Many people have dreams of severing their home from the grid, and running their entire home off of energy produced by solar anels. While the idea of being able to have a powered home during power outages sounds exciting, the magnitude of cost and maintenance involved in actually executing this dream prevents most people from making it happen. The main concern with using an off-grid system to power a home are the additional cost and maintenance of storing the power.
To store the power generated by the panels, batteries are required. These batteries make the system much more costly than a grid-tied system and also require more maintenance.
Practical Applications of Off-Grid Solar
Off-Grid Solar does have some practical applications. Power small DC powered machines such as Solar Water Pumps for remote site irrigation is a great application for Off-Grid Solar as it exists today. Even powering a one room shack or outpost in remote areas can be viable where there is no utility service present, or where it may be cost prohibitive to install service.