Life cycle optimization of sustainable energy systems within planetary boundaries

Abstract

Curbing carbon emissions in the power sector has become a priority to mitigate climate change, yet the sustainability implications of power generation decarbonization remain unclear. To shed light on whether current plans to decarbonize the electricity system would be enough to deliver sustainable energy, modeling frameworks able to achieve multi-criteria environmental analysis need to be developed. Firstly, this thesis combines multi-objective optimization, life cycle impact assessment and multivariate regression based on elasticities to quantify the occurrence and severity of burden-shifting in energy systems due to carbon policies. Secondly, it integrates thousands of life cycle inventories into the optimization of energy systems using monetization. Thirdly, it downscales and integrates planetary boundaries into the optimization of energy systems. Finally, it evaluates and optimizes the planetary boundaries performance of the global power sector in 2100 using data obtained from Integrated Assessment Models (IAMs). Results classify life cycle indicators into three categories: no burden-shifting, total burden-shifting and partial burden-shifting. Depending on the severity of the carbon target, burden-shifting to some life cycle indicators could take place. While meeting the Paris Agreement could generate indirect environmental savings, concurrently optimizing the direct and indirect costs of electricity generation would yield the highest environmental benefits. Few pathways developed via IAMs would operate within the planetary boundaries that all anthropogenic activities should share jointly in 2100, while all of them would exceed the share of budget allocated to the global power sector. Energy mixes in line with some carbon policies could transgress critical planetary boundaries, including those on climate change. Deploying bio-energy with carbon capture and storage hand-in-hand with renewables and nuclear plants is critical to minimizing the transgression of planetary boundaries while maintaining the grid’s reliability. This thesis, therefore, highlights the need to depart from carbon policies to multi-criteria environmental policies to power our development sustainably.