Assuming a 10 kW unit would be installed with an electrical efficiency of 8 to 10 % [10, 11, 12]. a 100 kW solar field would be required. This equals an aperture surface of 200 m². 200 m² with a price of 250 Euro installed would end up with a total investment of roughly 60,000 Euro including the assumed 10,000 Euro steam screw set up. For pure electricity production these costs are too high in comparison with other technologies, for example photovoltaic. The turbine can not be competitive in this size. If co-generation is required, then the situation changes as photovoltaic can not supply thermal heat. Assuming the steam screw produces electricity and afterwards the waste heat is used for cooling purposes, than this additional value needs to be taken into our calculation.