抄録
A direct-steam-generation (DSG) collector is expected to make it possible to improve solar thermal collection efficiency and the economics of a solar thermal power generation system. In this paper, characteristics and economics of two kinds of power generation systems using a DSG and a conventional collector are investigated: a CO2-capturing hybrid-type power generation system (Hybrid system) and a conventional solar thermal power generation system (STPG system). In evaluation, the total area of collector is assumed to be 10 ha and the capacity of each system was determined so as to minimize the unit power generation (UPG) cost. It has been shown through simulation study under assumed premises that for the STPG system the UPG cost is improved from 24.4 to 19.4 yen/kWh and that the net generated power quantity is increased by 30.8% by using a DSG collector. For the Hybrid system the UPG cost is improved from 15.8 to 14.9 yen/kWh and the net generated power quantity is increased by 17.5%. It has also been shown that CO2 reduction amount is increased from 2, 106 to 2, 759 t-C/y in STPG system and from 6, 282 to 7, 380 t-C/y in Hybrid system. The Hybrid system using a DSG collector is expected to be one of the most desirable power generation systems under the CO2 emission constraint in the future, since among investigated systems (a) it has the highest fuel-base power-generation-efficiency as high as 67.2%; (b) its UPG cost is the lowest; (c) it emits no CO2; and (d) its CO2 reduction effect is the largest.
