How efficient are the panels?
The performance of a photovoltaic array is dependent upon sunlight. Climate conditions (e.g., clouds, fog) have an effect on the amount of solar energy received by a PV array and, in turn, its performance. Most current technology crystalline photovoltaic modules are about 12 to 13 percent efficient in converting sunlight into electricity. Some modules provide as much as 20 to 21 percent efficiency. Further research is being conducted to raise this efficiency to 23+ percent.