Power-to-gas/iquids for Managing Renewable Electricity Intermittency in the Alpine Region

Large scale deployment of renewable energy sources (RES) can play central role in reducing CO₂ emissions from energy supply systems, but intermittency from solar and wind technologies present grid integration challenges. High temperature co-electrolysis of steam and CO₂, in the so-called power-to-gas (PtG) and power-to-liquid (PtL) configuration, could provide a path for utilizing the excess intermittent electricity from a power system by converting it into chemical fuels that can be directly utilized in other sectors, such as transportation and heating. The chemical fuels could also be used in the power sector during periods of deficit in supply. Here, the economic and engineering potential of PtG and PtL systems deployment is investigated as storage for intermittent renewable electricity and as a source of low-carbon heating and transportation fuels among the different energy sectors in the Alpine region, located in south-central Europe. The study is carried out using BeWhere model, initially developed at IIASA and Luleå University of Technology. BeWhere is a geographic explicit cost optimization model, based on mixed integer linear programming (MILP), written in GAMS and uses CPLEX as solver. For this work, BeWhere is used to investigate the impact of temporal and spatial intermittency of RES when planning synchronized decarbonization of energy supply system in the Alpine region. Results indicate large-scale deployment of the PtG and PtL technologies for producing chemical fuels from excess intermittent electricity is feasible, particularly when incentivized by carbon prices in the range of 50−200 Euro/tCO₂. During the sample year, depending on the assumed carbon tax and fossil fuel prices, the estimated power over-generation potential is found to be in the range of 0.7−105 GW, which results in annual total between 7 and183 TWh. In addition, large volumes of captured CO₂, as much as 30 Mt CO₂/year, are utilized in the synthesis of the chemical fuels, providing as much as a quarter of liquid transportation fuels consumption in the region. In this context, it can be concluded that PtG/PtL technologies can enable greater integration of RES into the energy supply chain, with application worldwide.