From a presentation by Swiss company CTU Clean Technology Universe AG comes this Sankey diagram for energy flows in a wood gas process.
The diagram is set up for wood with 50% humidity and an energy content of 1 MJ. The process steps drying, gasification, methanation, CO2 removal yield gas with an energy content of 0,71 MJ (71%). Much of the offheat is recovered in the process, excess heat is fed to district heating.
Wood in brown, gas in orange, heat in red and electricity in blue.
Another Sankey diagram for wood gas here.
