Nonrenewable energy cost and greenhouse gas emissions of a 1.5 MW solar power tower plant in China

It is commonly assumed that renewable energy based systems have the potential to mitigate greenhouse gas emissions and save fossil energy from the grid. Nevertheless, any energy conversion systems need extra energy to deliver energy into society. It is necessary to estimate the total direct and indirect fossil energy cost and associated greenhouse gas emissions by any system over its entire life cycle. For the first MW class solar tower power plant in China, nonrenewable energy cost and greenhouse gas emissions are accounted respectively as 0.95 MJ/MJ and 0.04 kg CO2-eq/MJ during its expected 20 years of operating life, corresponding to a net nonrenewable energy saving of 3.92E+08 GJ and greenhouse gas emission mitigation of 4.17E+04 tonne CO2-eq compared to conventional thermal power systems in China.