Comparisons of Different Types of Solar Power Systems
Here a comparison the various types of photovoltaic based systems shall be shown, particularly grid-tied solar systems, grid-tied solar system with battery backup, grid-tied system with generator backup, and off-grid solar power systems.
|Grid-Tied||Grid-Tied w/ Battery Backup||Grid-Tied w/ Generator Backup||Off-Grid|
|Typical Return on Investment||7-20%||5-10%||5-10%||<1%|
Replace Batteries every 5-10 Years
Periodically run generator, typical engine maintenance
|Replace Batteries every 5-10 Years, frequent battery maintenance if flooded batteries are used|
|Average Install Time||1day per kilowatt||2-3days per kilowatt||2 days per kilowatt||3 days per kilowatt|
|Power if Grid Goes Down||No||Critical circuits only||Critical circuits only||Yes, not connected to grid|
|Clean, renewable, solar power||Yes||Yes||Yes||Yes|
So Which Type of System is the Best for me?
This all depends on what your goals are. For the best return on investment, a standard grid-tied system is best. If you want a good investment and peace of mind in the event of a power grid failure, then a grid-tied system with backup makes sense. If you live in a remote area with no local utility power available, then an off-grid system is your only option.
Why is the Return on Investment so Small for an Off-Grid System?
Off-grid photovoltaic systems utilize a large number of batteries to store energy for around the clock use. These large batteries are expensive, and must be replaced every 5-10 years. This extra cost raises the amount of money you are spending per kilowatt-hour that you produce. In some cases the cost will exceed that which the utility company would charge for electricity. However, if you live in a very remote area that does not have local transmission lines, you would have to pay the utility company to install them, which could far outweigh the cost of an off-grid solar power system. Not to mention the environmental benefit of using clean renewable solar energy!