Life cycle assessment of high‐concentration photovoltaic systems

Abstract

The environmental profiles of photovoltaic (PV) systems are becoming better as materials are used more efficiently in their production, and overall system performance improves. Our analysis details the material and energy inventories in the life cycle of high‐concentration PV systems, and, based on measured field‐performances, evaluates their energy payback times, life cycle greenhouse gas emissions, and usage of land and water. Although operating high‐concentration PV systems require considerable maintenance, their life cycle environmental burden is much lower than that of the flat‐plate c‐Si systems operating in the same high‐insolation regions. The estimated energy payback times of the Amonix 7700 PV system in operation at Phoenix, AZ, is only 0.9 year, and its estimated greenhouse gas emissions are 27 g CO2‐eq./kWh over 30 years, or approximately 16 g CO2‐eq./kWh over 50 years. Copyright © 2012 John Wiley & Sons, Ltd.

Assessment of the Carbon Footprint, Social Benefit of Carbon Reduction, and Energy Payback Time of a High-Concentration Photovoltaic System

“…The tracking system was constructed using aluminum, steel, cement, and motor. The energy generated by HCPV without considering the degradation of efficiency was calculated using the following formula [12].…”

“…The HCPV system was suggested to be installed in a high DNI location [43], and the DNI values in Taiwan are significantly lesser than those in many places around the world. Thus, the locations with high DNI values were selected from other studies [12,43], and six cities were selected in the following sections: H1 (Phoenix, 2482 kWh/m 2 /year), H2 (Seville, kWh/m 2 /year), H3 (Tabuk, 2668 kWh/m 2 /year), H4 (Haixi, 2409 kWh/m 2 /year), H5 (Las Vegas, 2600 kWh/m 2 /year), and H6 (Calama, 3322 kWh/m 2 /year).…”

“…However, the real life expectancy of a PV system and the contract of the feed-in tariff in Taiwan were estimated to be at least 20 years [44]. Life expectancy could also be extended to 50 years by replacing the cells in the field; the inverter could be replaced every 15 years, and other structures could be replaced every 50 years [12]. Degradation rate is a very important factor for energy generation estimation (up to 10% of the energy generation estimate under degradation rate was considered in the 0.7% per year) when the life expectancy of the PV system was assumed to be 30 years [11].…”

“…Energy payback time (EPBT) is another widely used environmental indicator to assess the sustainability of an energy system [18]. The EPBT indicator is defined as the years required for a PV system to generate a given amount of energy for the compensation of total energy consumption across the life cycle of a PV system, which includes raw material, transportation, assembly, operation and maintenance, and end of life [12,19]. Jungbluth et al [20] compared different PV systems that were under the same irradiation (1117 kWh/m 2 /year) to assess the EPBT.…”

“…The results showed that the EPBT of the HCPV located in the Gobi Desert was two years in the first scenario, whereas that of the mc-Si PV in the second scenario was 1.73. Fthenakis and Kim [12] assessed the HCPV using Amonix 7700. Their findings indicated that the carbon footprint of HCPV was in the range of 26-27 g CO 2 eq/kWh (under an assumed life cycle of 30 years) and 16 g CO 2 eq/kWh (under an assumed life cycle of 50 years).…”