Energy analysis of different chemical storage options for carbon recycling purposes

The mid-term and long run climate change-driven energy roadmaps are promoting the use of renewables as low or zero carbon energy sources. Yet, their integration in current energy systems calls for solving balancing, security and matching issues. In this framework, energy storage is meant as a mitigation strategy in the transition towards Future Smart Energy Systems and it is often considered the " solution " for RES capacity firming. Another point of view to address directly the CO2 emissions mitigation is the Carbon Capture and Storage (CCS). Starting from this technology, many options are available to store CO2 so as to reduce their concentration in the atmosphere. A promising way is the combination of CCS and Power-toGas to produce synthetic fuels characterized by lower life cycle emissions value. The so-called chemical-storage provides the opportunity to link different energy infrastructures, i.e. Electricity Grid, Gas Grid, transport sector, etc. The willing to carbon recycle to address directly the IPCC targets has moved to the definition of future energy scenarios. Indeed, coupling the management of RES electricity excess by means of electrolyzers to produce Hydrogen and its combination with captured CO2 could be the key point in carbon emissions mitigation strategies. In order to evaluate the energy effectiveness of this solution, the authors of this study present an energy analysis to compare the synthetic methane, DME and methanol production processes. The involved chemical reaction showed diverse energy costs. Their profitability was evaluated along with their final use, i.e. energy production, transport fuel and direct injection into the Gas Grid