The carbon mitigation potential of emerging photovoltaic technology

Abstract

Photovoltaic systems provide a solution for harnessing energy from the sun whilst reducing global greenhouse gas emissions. Organic photovoltaics (OPV), based on blends of polymer and fullerene materials, have recently received widespread interest within academia and business due to its potential for low costs, minimum environmental impact and rapid roll-to-roll manufacture. In addition, modules can be customised for flexibility, light-weight and colour. However, OPV modules also show considerably lower efficiencies than mature photovoltaic technologies, as well as much reduced lifetimes.

This thesis presents a framework for the analysis of the potential for GHG mitigation by assessing how unique characteristics of the technology may influence its GHG mitigation potential. In the first instance, the extent to which OPV can realise the goal of low costs and minimal environmental impact is assessed. This analysis shows that GHG emissions from OPV manufacture are considerably lower than mature PV technologies. However, the economic cost of OPV, whilst lower on the basis of capital costs, struggles to compete on a levelised basis assuming current projections for lifetime, suggesting that the technology will only have an impact on GHG mitigation outside conventional PV applications.

Two potential niche applications are analysed as case-studies. Analysis of using OPV materials as a partially transparent coating in greenhouse structures concludes that currently available OPV materials can provide significant power with minimal impact on crop growth. However, partial coverage with opaque crystalline silicon modules can provide more electricity with less impact on crops. The second case-study looks at the application of OPV in providing off-grid lighting, assessing the emissions and costs associated with this application as well as looking at the long term degradation of OPV in the harsh environments, through a field trial of the technology in Southern Rwanda.

Finally, analysis of the transition to solar energy technology shows that OPV can provide much more rapid emission reductions in comparison to mature technology, despite higher levelised emissions.

This work concludes that organic photovoltaic technology may be limited to a few niche applications where inferior performance does not present a challenge, or unique properties are advantageous. However, the application case-studies presented in this thesis show a large GHG mitigation potential from such applications, and analysis of the transition to PV demonstrates the added advantage of OPV in realising rapid emission reductions.