Analyses and comparison of energy systems and scenarios for carbon neutrality – Focus on the Americas, the MENA region, and the role of geo-technologies

Abstract

Energy systems underpin the economic growth of nations but are contributing to worsening climate change in the current state dominated by fossil fuels. Transitioning to a fossil-free renewables-based energy system is essential to decrease the impact of climate change across the world, which is compatible with the Paris Agreement and the UN SDGs. However, it is crucial to consider appropriate investments in renewable energy (RE) prior to and in line with the phasing-out of fossil fuels for an orderly transition worldwide. If these actions are delayed, the respective consequences on climate and ecosystems become increasingly hard to overcome. Current global events reflect the delicate nature of the global energy system that is based on fossil fuels with regard to increasing costs and insecurity of the energy system.

This dissertation aims to analyse the energy transition based on 100% RE through energy system modelling under various system configurations, constraints, and scenarios within the context of two major regions in the world, the Americas and the MENA region. The techno-economic feasibility of shifting away from a fossil-dominated power system towards a 100% RE-based system is investigated in both regions for 2030 conditions. The role of sector coupling is explored through the integration of seawater desalination and non-energetic industrial gas demand. Furthermore, Iran and Chile, as two representatives of each major region located in the Sunbelt region, are selected with their unique energy system structures to transition towards a fully RE-based system by 2050 in 5-year intervals, from 2015 to 2050. A comprehensive assessment and comparison are conducted for the energy transition pathways under an identical modelling environment and uniform assumptions for the electricity sector. All the energy system modelling in this dissertation is performed by the LUT Energy System Transition Model. The model is a linear programming technique based on investment optimisation that includes multiple features such as spatially-resolved, temporally-resolved, cross-border transmission network, and sector coupling. Additionally, the resource potential of compressed air energy storage (CAES) and enhanced geothermal systems (EGS) are evaluated.

The global CAES potential, analysed through a GIS-based model, was estimated at 6574 TWhel storage capacity worldwide which can contribute to high penetration of RE. Moreover, a global estimate of EGS was presented in a 1˚×1˚ spatial resolution under theoretical, technical, economic, and sustainable constraints. The economic and sustainable potential was found to be at 108 TWe and 256 GWe, respectively, by 2050. Regarding the energy transition studies, solar photovoltaics and wind power together with battery storage are the main drivers of the energy transition, complemented by other RE and energy storage technologies. Cross-border grid interconnections can decrease the need for energy storage while decreasing the total system costs. Moreover, the hypothesis of great benefits that can be achieved through linking North and South America over a long-distance grid interconnection was examined. The results revealed that fully interconnected Americas lead to a decrease of just 1.4% of the LCOE than separated North and South America. High electrification and sector coupling are identified as the cornerstone of the fully balanced and optimised energy system, as they increase the overall system efficiency while declining the total system costs. Various flexibility measures would smoothen the energy supply across all sectors, such as energy storage, grid interconnections, and power-to-X. The role of e-hydrogen was found to be important as it can be used directly and indirectly for e-fuels production. In the heat sector, powerto- heat presented the least-cost solution, either by heat pumps or via electric heating, in the Chilean energy system. These components were complemented by biomass, concentrated solar thermal power, and geothermal energy in a Best Policy Scenario aiming to achieve a 100% RE system by 2050.

Thanks to low-cost electricity from solar photovoltaics and wind power, which can be complemented by other RE sources and energy storage, future energy systems can run uninterrupted throughout the year without relying on fossil fuels (with or without carbon capture and storage) and nuclear power. Such a transition can pave the way for shifting away from fossil fuels in all energy sectors towards a carbon-neutral and sustainable energy system by 2050. In addition, the role of desalinated water as an alternative source for water production was found crucial for various purposes to tackle the growing water demand, especially in the MENA region which is one of the most water-stressed in the world. It is hoped that the key takeaways from this research help governments, policymakers and the public society better understand how to shift away from the conventional energy system towards a fully sustainable, renewable, and competitive system for all by mid-century.