Life cycle assessment of crystalline photovoltaics in the Swiss ecoinvent database

Abstract

This paper describes the life cycle assessment (LCA) for photovoltaic (PV) power plants in the new ecoinvent database. Twelve different, grid-connected photovoltaic systems were studied for the situation in Switzerland in the year 2000. They are manufactured as panels or laminates, from monocrystalline or polycrystalline silicon, installed on facades, slanted or flat roofs, and have 3 kW p capacity. The process data include quartz reduction, silicon purification, wafer, panel and laminate production, mounting structure, 30 years operation and dismantling. In contrast to existing LCA studies, country-specific electricity mixes have been considered in the life cycle inventory (LCI) in order to reflect the present market situation. The new approach for the allocation procedure in the inventory of silicon purification, as a critical issue of former studies, is discussed in detail. The LCI for photovoltaic electricity shows that each production stage is important for certain elementary flows. A life cycle impact assessment (LCIA) shows that there are important environmental impacts not directly related to the energy use (e.g., process emissions of NO x from wafer etching). The assumption for the used supply energy mixes is important for the overall LCIA results of different production stages. The presented life cycle inventories for photovoltaic power plants are representative for newly constructed plants and for the average photovoltaic mix in Switzerland in the year 2000. A scenario for a future technology (until 2010) helps to assess the relative influence of technology improvements for some processes. The very detailed ecoinvent database forms a good basis for similar studies in other European countries or for other types of solar cells.

Photovoltaics energy payback times, greenhouse gas emissions and external costs: 2004–early 2005 status

“…The results from these two studies were widely circulated and especially the ExternE publication with its official status is likely to have influenced policy decisions with regard to energy technology. More recent (i.e., 2000) data are included in the Ecoinvent data base 12 and these are expected to be used in future updates of the ExternE project. Our present paper updates all these estimates and shows the energy payback times of current (i.e., 2004-2005) PV systems, based on actual manufacturers data from several independent sources.…”

Life cycle analysis of organic photovoltaic technologies

“…emissions per kWh of produced energy for an average southern European isolation have a clear advantage over coal (900), gas combined cycle (439) and even nuclear (40) (see e.g. References [8,9]). Also a detailed comparison of energy payback times and emissions for different photovoltaic technologies has been carried out where most attention has been devoted to monocrystalline (mono-Si) and multicrystalline (multi-Si) silicon modules since they are the most often used PV technologies with a 93% share of the market in 2006 [9][10][11].…”

Environmental impact of thin-film GaInP/GaAs and multicrystalline silicon solar modules produced with solar electricity

“…The PV modules are considered to have an expected lifetime of 30 years (Jungbluth 2005;Ecoinvent Centre 2007;United Nations Environmental Program 2008).…”