The relative aggregate footprint of energy generation across the globe
File(s)
Author(s)
Mahlooji, Maral
Type
Thesis
Abstract
Immediate increase in contribution of renewables is considered as a quick fix to climate change. However, decarbonising energy portfolios can lead to adverse secondary impacts on other environmental resources. Thus, ambiguity remains around the best performing alternatives with respect to the nexus of impacted resources. This research has established the importance of Relative Aggregate Footprint (RAF) in analysing the overall sustainability and performance of energy alternatives. The RAF is an index computed by multi-criteria assessment through implementation of a System of Systems (SoS) approach. This framework addresses performance value uncertainties, whilst criteria priority can be set based on local resource availability/limitation conditions. The aggregate footprint of alternatives are evaluated based on multiple notions of optimality for increased robustness of the results. The RAF concept is then incorporated with financial portfolio theory, where the risk and return of each energy mix (portfolio) are computed to determine its desirability. The return reflects the overall aggregate footprint (RAF score) of the portfolio, whilst the deviation from the expected return presents the portfolio risk. This approach provided insight on the impact of increasing the share of renewables and diminishing fossil fuels on the aggregate footprints of a portfolio.
The study evaluates the performance of 11 energy technologies with respect to carbon, cost, water and land footprints as well as local resource availability conditions for all countries around the world. Based on the results, energy RAFs vary greatly across the globe, indicating the dependency of overall desirability of energies on local conditions, i.e. not all renewables are equally desirable across all countries once their aggregate impacts are accounted.
The portfolio outcomes indicate that increased contribution from all renewables does not lead to portfolios with lower RAFs (high returns), or lower risk levels. Incorporation of fossil fuels in combination with appropriate renewables, selected based on local availability conditions, delivered the most diversified portfolios, which often increased the return (decreased the RAF score) for a given risk level.
The study evaluates the performance of 11 energy technologies with respect to carbon, cost, water and land footprints as well as local resource availability conditions for all countries around the world. Based on the results, energy RAFs vary greatly across the globe, indicating the dependency of overall desirability of energies on local conditions, i.e. not all renewables are equally desirable across all countries once their aggregate impacts are accounted.
The portfolio outcomes indicate that increased contribution from all renewables does not lead to portfolios with lower RAFs (high returns), or lower risk levels. Incorporation of fossil fuels in combination with appropriate renewables, selected based on local availability conditions, delivered the most diversified portfolios, which often increased the return (decreased the RAF score) for a given risk level.
Version
Open Access
Date Issued
2019-10
Date Awarded
2020-04
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Madani, Kaveh
Publisher Department
Centre for Environmental Policy
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)