The energy situation in both process industries andpower plants is changing and it is of interest toinvestigate new polygeneration solutions combiningproduction of chemicals with the production of powerand heat. Examples of such chemicals are methane,hydrogen, and methanol etc. Integration of gasificationinto chemical recovery systems in the pulp and paperproduction systems and into the combined heat andpower (CHP) systems in power plant applications areamong the possible polygeneration systems. It is alsointeresting to look at the potential to introduce combinedcycles with gas turbines and steam turbines as acomplement. To perform such analysis, it is importantto have relevant input data on what gas composition wecan expect from running different type of feed stock. Inthis paper, we focus on the wood pellets. Experimentalresults are correlated into partial least squares models topredict major composition of the synthesis gas producedunder different operating conditions. The qualityprediction models then are combined with physicalmodels using Modelica for investigation of dynamicenergy and material balances for large plants. The datacan also be used as input to analysis using e.g. ASPENplus and similar system analysis tools.