A novel technology for liquefied synthetic natural gas production powered by renewable electricity: Process development and impact analysis on vehicular transportation

Overgeneration of wind energy conversion systems represents a grid issue, limiting the growth of renewable energy utilization. Alternative fuels utilization such as liquefied natural gas is emerging as a new market with a big potential in freight transport. In order to mitigate wind energy production curtailment, a power to liquefied synthetic natural gas process is proposed. Solid oxide electrolyser and catalytic methanation integrated system is applied to produce hydromethane. After a dehydration step in a temperature swing adsorption unit, low temperature gas upgrading techniques are applied for the first time to hydromethane mixture. Liquified synthetic natural gas is produced, meeting grid injection and endothermic engines requirements after regasification. A higher energy efficiency with respect to the application of traditional technologies is achieved. Plant configuration was optimized for internal thermal and chemical energy recovery and exploitation, achieving an overall electrical to chemical efficiency of about 50%. A case study was analyzed for the Irpinia (Italy) territory, strongly affected by wind energy overgeneration. Impact on local transport infrastructure was assessed through well-to wheel analysis, considering the use of produced liquified synthetic natural gas in heavy duty vehicles. Greenhouse gas avoided emissions are expected to correspond to 7.1% of the vehicular emissions related to local traffic statistics for 2016.