A Co 2 -capturing Hybrid Power Generation System with High Efficient Use of Solar Thermal Energy

A CO 2 -capturing hybrid-type power generation system with highly e cient use of solar thermal energy was proposed and its characteristics were investigated. In the system, relatively low temperature saturated steam is produced using solar thermal energy and is used as the working uid of a methanering gas-turbine system. The solar thermal utilization e ciency becomes considerably high compared with that of conventional solar thermal power plants in which superheated steam near 670 K is used as the working uid of steam turbines. The proposed system is a hybrid-type energy system in which the generated CO 2 is recovered based on combusting oxygen, and thus a highly e cient system without emissions of CO 2 and NO x can be expected to be constructed even in regions with poor solar insolation. The characteristics of the system with 10,000 m 2 collector area were estimated based on a computer simulation model. It has been estimated through simulation study that the net generated power is 1.55 MW, the capacity factor is 21.5%, the total exergetic e ciency is 20.9% when the temperature of the saturated steam is 496 K. It has also been shown, when calculated on the basis of consumed fuel, that the net thermal e ciency of the system is 63.7%, being higher than 46% compared with that of the conventional power plant with 43.5% e ciency.