Understanding the divergence in EROI for solar PV
Some analyses calculate an EROI for solar PV of 60:1 or higher, while some calculate a much lower EROI, in one recent case, less than 1:1. The casual observer could be forgiven for wondering what’s going on. Since there is such a wide divergence, the default response seems to be to gravitate towards the results that reflect a individual’s worldview rather than trying to understand the role of solar PV in energy transitions.
Here is a shortened abstract:
Solar photovoltaics (PV) is widely regarded as one of the most promising renewable energy technologies. Results across studies can appear to diverge sharply, which leads to contestation of NEA’s relevance to energy transition feasibility assessment. This study explores how PV NEA approaches differ, including in relation to goal definitions, methodologies and boundaries of analysis. Here we show that most of the apparent divergence between studies is accounted for by six factors—life-cycle assessment methodology, age of the primary data, PV cell technology, the treatment of intermittency, equivalence of investment and output energy forms, and assumptions about real-world performance. The apparent divergence in findings between studies can often be traced back to different goal definitions. This study reviews the differing approaches and makes the case that NEA is important for assessing the role of PV in future energy systems, but that findings in the form of EROI or EPBT must be considered with specific reference to the details of the particular study context, and the research questions that it seeks to address. NEA findings in a particular context cannot definitively support general statements about EROI or EPBT of PV electricity in all contexts.
The aim of the study was to understand the reasons for the divergence rather than put a single figure in the conclusions. At one level, solar PV can be thought of as an efficient way to convert fossil fuels to electricity. In other words, investing fossil-fuelled electricity into solar plants will provide much more electricity over the PV lifetime. Within the context of our incumbent energy systems, the result is unambiguous – PV produces much more energy over its lifetime than is invested in its production.
The question arises as to how effective solar is at bootstrapping its own energy to increase the stock of PV, and substituting for the whole suite of electricity assets and energy services, including transport. In the long-run, there is much more uncertainty as to the value of PV in replacing incumbent infrastructure. Do read the paper.