Samenvatting

The environmental impact of Synthetic Natural Gas (SNG) production from wood gasification is analysed, focusing on the comparison of two continuous processes (CO2 removal and Fuel-assisted hydrogen addition) to balance the gas mix for the methanation, and their coupling to an intermittent process (Full electric hydrogen addition). The third process increases the SNG production - with the same wood input-, and operates only when surplus electricity is available. The analysis is done through a comparative life cycle assessment (LCA) of the production streams, without including SNG plant infrastructure. The production of SNG can be a tool to balance the electricity production with a high share of fluctuating renewables and the gas grid. The research is located in the framework of the Synthetic methane project of the Energy Delta Gas Research (EDGaR). The results show that CO2 removal has lower environmental impact and lower electricity consumption, which could derive economic advantages. The larger electricity consumption of Fuel-assisted hydrogen addition (FA) result in larger environmental impact, especially if the electricity is not produced nearly 100% by renewable sources. A slightly lower CO2 removal wood consumption does not determine the environmental impact differences. If FA is to compete with CO2 removal, the surplus heat has to be used to replace a fuel with an environmental impact similar or larger than natural gas.