Adequate battery or other storage is required to provide energy during cloudy and foggy periods. Because of the high variability of the solar resource in Iowa, using a tracking device to follow the sun during the day does not appear to be practical. The optimum PV configuration is an array of fixed modules at an angle of 42 degrees relative to the horizon. Because of the extensive amount of scattered light due to cloud cover, haze and fog, there may be some advantage to amorphous rather than polycrystalline or single crystal modules. The solar insolation data were compared with Ames Municipal Utility demand data over the course of a year.
High temperatures demand more energy use for air conditioning.
Not surprisingly the solar insolation peaks at the same time so that photovoltaics offer a good fit with peaking utility demand. A comparison of potential wind energy with solar insolation and utility load data needs to be completed. The location of the test facility was not, however, satisfactory for collection of wind data. All photovoltaic modules on the test facility functioned normally throughout the test period. The Iowa environment does affect the packaging of the modules and, in particular, corrosion was observed around electrical contacts.