Advantages of operation flexibility and load sizing for PV-powered system design. (1st March 2018)

• Record Type: Journal Article
• Authors: Watson, Sterling; Bian, David; Sahraei, Nasim; Winter, Amos G.; Buonassisi, Tonio; Peters, Ian Marius
• Is Part Of: Solar energy. Volume 162(2018)
• Page Start: 132
• Page End: 139
• Publication Date: 2018-03-01
• Subjects: PV-powered systems -- System design -- Desalination; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2018.01.022
• Languages: English
• ISSNs: 0038-092X

Abstract

Highlights: Cost reductions were enabled by time-flexible operation and load sizing for PV-powered systems. Examined a theoretical reference system and an actual PV-powered EDR system in Chelluru, India. 39% cost reduction for the power system achieved due to time-flexible load operation. Additional 5% cost reduction demonstrated due to optimizing the period of operation. Abstract: With their autonomous operation and low environmental impact, solar photovoltaics (PV) are an attractive power source for off-grid systems. However, the variable nature of solar energy is not well-suited to power conventional loads. Without careful consideration of the time-dependent power generation of PV, this discrepancy results in systems that are either over-designed and expensive, or compromise reliability. To accelerate the adoption of PV into new areas, it is essential to design PV-powered systems that are persistent, predictable, and affordable. In this paper, we analyze the cost reductions enabled by design optimization through time-flexible operation and improved load sizing. We consider two cases: (i) an idealized reference system, operating 8 h per day at 1 kW, generating an unspecified accumulable output, and (ii) a village-scale PV-powered electrodialysis desalination system, designed to generate 10 m 3 of drinking water per day. We found that time-flexible load operation reduced the power system cost of the idealized reference system by 39%, from $2662 to $1628, and designing its electrical load to operate for an optimal period of time enabled an additional cost reduction of 5% (to $1503). For the village-based desalination system, we found that flexible operation paired with expected large decreases in membrane cost (from $150 to $20 per unit) reduced the associated power system cost by 57.6% from $8935 to $3788.