function [CO2, H2O, CO, H2] = read_component_data(T)
% read component data from excel sheet in same folder to handle Delta_f_G0
% at different temperatures
% n0 = 2, in kmol

    table = readtable('comp_data.xlsx');
    % 1300 K
    if T == 1300
        n = 4;
    end
    
    CO2.n0 = table2array(table(2,"CO2"));
    H2.n0 = table2array(table(2,"H2"));
    CO.n0 = table2array(table(2,"CO"));
    H2O.n0 = table2array(table(2,"H2O"));
    
    % molar mass of species in table row 1 in kg/kmol
    CO2.M = table2array(table(1,"CO2"));
    % CH4.M = 16;
    H2O.M = table2array(table(1,"H2O"));
    CO.M = table2array(table(1,"CO"));
    H2.M = table2array(table(1,"H2"));
    
    % TODO: element structures need to be returned
    % molar mass of elements in kg/kmol
    C.M = 12;
    O.M = 16;
    O2.M = 32;
    
    H2O.Delta_f_G0 = table2array(table(n,"H2O"));
    CO.Delta_f_G0 = table2array(table(n,"CO"));
    CO2.Delta_f_G0 = table2array(table(n,"CO2"));
    H2.Delta_f_G0 = table2array(table(n,"H2"));
end