A methodology to evaluate photvoltaics: storage as a commercial customer initiated demand side management tool

While photovoltaic research conducted to date has been primarily in the areas of utility peak shaving, residential applications, and stand alone applications, this research examines photovoltaic potential as a commercial customer initiated demand side management tool and develops a methodology which can be used to evaluate the value of a PV storage system. The primary focus is on the effect photovoltaic orientation and utility billing practices have on overall system value. Using a year's worth of 10 minute data collected at the Virginia Tech Solar Experimental Station and an academic building load, the effects of array orientation on clear sky photovoltaic production and the match between that production and the building load profile are discussed.

The performance of five photovoltaic array configurations for both building energy and demand reduction were simulated. It was shown that arrays facing south-southwest and southwest have lower performance that a south facing array in spite of the presence of an afternoon building load peak.

The impact of battery storage as a supplement to a PV system has been examined. The affect of battery efficiency, array orientation, and battery dispatch setpoint on ovarall system value has been investigated. Based on economic assumptions and billing schedules obtained from a medium sized utility, the present value of the various array performances were evaluated. It was found that O&M costs could significantly effect the value being assigned to array configurations with superior performance. Due to the variability of the available insolation, smaller arrays have a greater value than larger arrays. It was shown that the value of a PV storage system is greater than either of the two component systems taken alone. By adding battery storage to the PV system, the optimum system size was increased.