Authors: S. Bankier, S. Gale
Energy Bulletin, June 16, 2006
Abstract
The energy payback time of photovoltaic (PV) cells has been a contentious issue for more than a decade.
Some studies claim that the joule content of the energy and materials that were put into the process of making the PV cell, will be equaled by the joule content of the electrical output of the cell within a few years of operation. Other studies claim that the useful electrical energy output of the PV cell will never exceed the total amount of useful energy contained within all the inputs of the manufacturing, installation and lifetime operating processes of the PV cell. These studies are often loosely referred to as measuring the energy "payback" of the PV cell. This study undertook a literature review to determine the key assumptions and considerations included in PV Life Cycle Analysis (LCA) modelling. In addition, other forms of modeling such as embodied energy (EE) analysis have also been considered.
This review has concluded that the likely energy payback of a typical domestic sized rooftop grid connected PV cell is approximately four years. In addition, it was estimated that larger utility PV cell power stations would have a much longer energy payback period.
