To achieve the Paris Agreement’s long-term temperature goal, current energy systems must be transformed. Australia represents an interesting case for energy system transformation modeling: with a power system dominated by fossil fuels and, specifically, with a heavy coal component, there is at the same time a vast potential for expansion and use of renewables. We used the multi-sectoral Australian Energy Modeling System (AUSeMOSYS) to perform an integrated analysis of implications for the electricity, transport, and selected industry sectors to the mid-century. The state-level resolution allows representation of regional discrepancies in renewable supply and the quantification of inter-regional grid extensions necessary for the physical integration of variable renewables. We investigated the impacts of different CO2 budgets and selected key factors on energy system transformation. Results indicate that coal-fired generation has to be phased out completely by 2030 and a fully renewable electricity supply achieved in the 2030s according to the cost-optimal pathway implied by the 1.5 °C Paris Agreement-compatible carbon budget. Wind and solar PV can play a dominant role in decarbonizing Australia’s energy system with continuous growth of demand due to the strong electrification of linked energy sectors.

Proposed emission reduction targets and the scarcity of fossil fuel resources make a transition of the energy system towards an emission-free electricity supply necessary. Australia represents an interesting case for energy system transformation modelling. While it currently has a power system dominated by fossil fuels, and specifically with a heavy coal component, there is a vast potential for expansion and use of renewable energy, in particular solar and wind energy. However, integrating high shares of such variable renewable energy sources challenges the power system due to their temporal fluctuations and geographical dispersion. This paper applies a state-resolved energy system model for Australia, based on linear optimization. We investigate the cost-optimal configuration of a renewable-based Australian power system and its transformation pathway inline with the ambitious proposed climate targets. We particularly analyze the implications of storage and power transmission grid extensions in a prospective, highly renewable Australian power system. Spatial smoothening effects of a powerful transmission grid reduces the required backup and renewable capacities and thus contributes to further reduction of the total system costs.

<p>Australia represents an interesting case for energy system transformation modeling.  Wile it currently has a power system dominated by fossil fuels, and specifically with a heavy coal component, there is also vast potential for expansion and use of renewable energy.  Geographically, the country is divided into seven states and territories, two of which have power systems isolated from the rest of the country. Regions have widely differing characteristic energy mixes and resources, ranging from high reliance on brown coal (Victoria), black coal (New South Wales, Queensland), natural gas (Northern Territory, Western Australia) to states that have already moved toward renewable energy-dominant systems (South Australia, Tasmania). Renewable power systems across Australia are experiencing rapid growth, particularly in solar photovoltaics and to a lesser extent with wind power and battery storage. </p><p>In order to better understand the further potential expansion of renewable power systems in Australia, we developed the Australian Energy Modelling System (AUSeMOSYS) based on the open-source OSeMOSYS framework. We apply AUSeMOSYS to investigate cost-optimal transformation pathways towards a carbon-neutral energy system. The model is calibrated carefully to recent past trends in energy generation, including the recent and near-future rapid uptake of renewables in different regions, whether by policy decision or autonomous development.  Beyond the power sector, AUSeMOSYS also provides scenario pathways for the uptake of electric vehicles and hydrogen powered transport, coupled to the power sector with a timeline through 2050. In order to investigate the full extent of renewable energy expansion given Australia’s recognized large renewable energy resource potential, we link selected industrial sectors to the power system model, e.g. steel production, where use of electric generation can further decarbonize Australia’s economy via hydrogen production and use.</p><p>In addition to the results showing the potential for large, integrated, cross-sectoral penetration of renewable energy into the Australian energy mix, we investigate modeling sensitivities to key parameters that can affect the uptake and use of renewable energy in the power system. For example, we study sensitivities in the choice of time-step resolution, the availability of trade between states in the National Energy Market (NEM) and the choice of carbon price and carbon cap pathways that can lead to near-zero emissions from the energy system by mid-century.</p>

<p>South Korea’s current energy system heavily relies on fossil fuels in particular coal-fired generation followed by nuclear. Currently, the country is defining its long-term energy strategy and latest Basic Electric Power Supply and Demand Plan proposes to increase the share of renewable energies to 26% by 2034, while converting most of their older half of coal plants to LNG. However, to be consistent with Paris Agreement compatible pathways, more ambitious coal phase out schedules to retire the entire coal fleet until 2030 are also discussed. We consolidate such a schedule with an expansion plan for wind and solar capacities derived from open-source renewable resource and energy system models.</p><p>For the analysis of integrating renewable energies into South Korea’s future energy system, we perform a detailed assessment of the technical potential of renewable energy sources by applying a temporally and spatially resolved modelling. A comprehensive set of geographical constraints and land exclusion factors are applied to derive the suitable area for placement of wind onshore and offshore turbines as well as PV installations. The land eligibility analysis is followed by the simulation of generation profiles from wind turbines and PV units from ERA-5 weather data, deriving the hourly capacity factors and the corresponding levelized cost of electricity for each location.</p><p>We optimize the expansion and operation of renewable energies and storage in South Korea’s electricity system for a Paris Agreement compatible coal phase out until 2030. The model chooses from the renewable expansion potentials and their cost characteristics derived in the resource assessment to balance an hourly-resolved demand scenario for each year. Flexibility needs are met with an optimized dispatch of the existing gas power plants and additional short-term and long-term storage capacities. The detailed modelling approach at a high temporal and spatial resolution allows to have a realistic assessment of the power system integration impacts of varying renewable sources and to evaluate the system adaptation needs in terms of required storage capacities.</p>