Adjustments to the design of a PV system will need to be made according to the site’s microclimate and other local circumstances. For instance, in Colorado, where afternoon clouds are frequent, a more southeasterly array orientation may be favorable, so that the array can receive more direct sunlight when it is available. Similarly, in coastal Central and Northern California, where mornings are often foggy, a more westerly orientation can be beneficial.
Also consider your utility rate structure. Some utilities offer “time of use” (TOU) metering programs—charging more per KWH during peak consumption times, generally mid-afternoon. In states like California, where the grid experiences huge summertime afternoon air-conditioning loads, these rate structures are helpful in keeping grid usage within bounds. TOU programs penalize peak users and reward peak producers in an effort to meet afternoon loads without having to build more generation capacity. That’s good news for PV system owners who can get greater net billing KWH credit by making sure their systems perform optimally during those peak times. To capitalize on peak selling rates, systems should be oriented and tilted toward the sun during those hours. And by reducing energy consumption during peak rate times, you can further increase your financial benefit from TOU rates.