Impacts of model structure, framework, and flexibility on perspectives of 100% renewable energy transition decision-making

As the discourse surrounding 100% renewable energy systems has evolved, several energy system modelling tools have been developed to demonstrate the technical feasibility and economic viability of fully sustainable, sector coupled energy systems. While the characteristics of these tools vary among each other, their purpose remains consistent in integrating renewable energy technologies into future energy systems. This paper examines two such energy system models, the LUT Energy System Transition model, an optimisation model, and the EnergyPLAN simulation tool, a simulation model, and develops cost-optimal scenarios under identical assumptions. This paper further analyses different novel modelling approaches used by modellers. Scenarios are developed using the LUT model for Sun Belt countries, for the case of Bolivia, to examine the effects of multi and single-node structuring, and the effects of overnight and energy transition scenarios are analysed. Results for all scenarios indicate a solar PV dominated energy system; however, limitations arise in the sector coupling capabilities in EnergyPLAN, leading it to have noticeably higher annualised costs compared to the single-node scenario from the LUT model despite similar primary levelised costs of electricity. Multi-nodal results reveal that for countries with rich solar resources, high transmission from regions of best solar resources adds little value compared to fully decentralised systems. Finally, compared to the overnight scenarios, transition scenarios demonstrate the impact of considering legacy energy systems in sustainable energy system analyses.