Thesis title: Open-source modelling of the Greek energy system featuring high spatial and temporal granularity for assessing and supporting national climate policy

Abstract: The transformation of the energy sector, and particularly electricity generation, constitutes the first line of defence in tackling climate change at the global, European, and national levels. Given the key role of energy consumption in everyday life and economic activity, the decarbonisation of the power generation sector becomes particularly complex, rendering energy policymaking challenging. From this perspective, the development and application of energy-system modelling tools become essential to evaluating alternative energy transition scenarios toward carbon-neutral economies. The aim of this dissertation is to investigate how the Greek energy sector is modelled, identify scientific gaps, develop an open-source modelling tool based on the open-source OSeMOSYS modelling framework that is capable of studying the Greek power generation sector and its decarbonisation in detail, and apply it to help underpin national energy and climate policy in the light of critical emerging research questions.

Initially, a detailed mapping of the problem space is conducted, consisting of (a) a systematic literature review of the energy modelling landscape for Greece over the past decade, and (b) a detailed overview of OSeMOSYS applications. In the former, despite the abundance of relevant publications, significant gaps are identified concerning geographical detail, temporal resolution, openness, and representation of complex technological issues such as power curtailment of variable renewable energy sources (RES), hourly electrical load distribution, energy storage, and interregional and cross-border electricity flows. Focusing on the issue of open science and examining the applications of the OSeMOSYS framework, the overview identifies similar gaps, noting that OSeMOSYS has not been extensively used in the context of the Greek energy sector, nor that of bridging the reviewed instrumental gaps.

Subsequently, an initial version of an OSeMOSYS model for Greece is developed and combined with the LEAP energy demand simulation model as well as a fuzzy cognitive mapping methodology. The aim of this application is to evaluate the transition of the Greek electricity sector up to 2035, towards eliminating the country’s dependence on Russian natural gas imports, in the aftermath of the Russian invasion of Ukraine. By exploring different scenarios restricting RES technologies in response to stakeholder input (including the risk of non-materialisation of geothermal power generation and wind power deployment exclusively outside zones of environmental interest), it is established that Greece can achieve its mid-term electricity-sector decarbonisation goals. It is noted, however, that the employed modelling tool in the study lacks geographic detail at the sub-national level as well as omits important technological innovations such as energy storage, thereby aligning with the scientific gaps highlighted in the literature review.

The dissertation then proceeds to the development of an integrated modelling tool for the Greek power generation sector, HERMES, with the aim of bridging said gaps. Emphasis is placed on the open-source code innovations within the new model, the introduction of new technological capabilities, the enhanced temporal resolution of the optimisation framework, and notably the improved geographic granularity through breaking down Greece into 10 mainland NUTS-2 regions and 11 islands.

Beyond presenting its novelties and validation process, HERMES is eventually used in two studies, including on (a) the regional implications of national energy policy on the decarbonisation of the power generation sector, and (b) the extent to which the National Energy and Climate Plan (NECP) can align with biodiversity constraints to onshore and offshore wind farm siting. The two applications present results at both the national and regional levels, highlighting all the innovative approaches incorporated into the HERMES model and, in turn, its added value compared to existing energy modelling tools.

Keywords: climate change, energy transition, literature review, energy models, economic cost optimisation, OSeMOSYS, HERMES, power generation, Greece, NECP, wind energy, RES, energy storage, time analysis, geographical detail, open source

Supervisor: Haris Doukas

PhD Student: Anastasios Karamaneas