A solar thermal wind tower (STWT) is a low-temperature power generation plant that mimics the wind cycle in nature, comprising a flat plate solar air collector and central updraft tower to produce thermal wind that drives turbines to generate electricity. The development of power generation systems toward a sustainable future needs to be made taking into account the balance between environmental impact and economic feasibility. We examine the sustainability of STWT power generation technology using the inclusive impact index light (Triple I-light), which estimates whether it is good to do the project, including both the negative environmental impact and the economic aspect. Environmental disadvantages are discussed by performing a CO2 inventory analysis for the life-cycle of the STWT power plant. Evaluation of the economic feasibility is done by calculating the levelized electricity cost (LEC), which is the cost per unit of electricity generated. From the calculations, it is found that overall system efficiency is increased by enlarging the capacity, the negative environmental impact by the STWT plant comes mainly from manufacturing stage (more than 60%), and the levelized electricity cost is dramatically decreased by enlarging the capacity of the system (about 50% reduction). A negative value of Triple I (meaning it is sustainable) can be achieved for high power generation capacity (above 100 MW). Moreover, this paper discusses the implementation and the potential of constructing offshore STWTs.

To facilitate sustainable energy development, one has to understand the limited availability of nonrenewable energy resources, and the ability of the earth to renew or recover. Emergy is an instrument that measures environmental loading, ecological economics, and regional sustainable development. In this study, emergy indicators are calculated to investigate the sustainability of solar updraft tower (SUT). SUT produces energy from the hot air, utilizing a combination of a solar collector, central tower, and air turbines. The results demonstrate that the sustainability of SUT grew as the size of the plant increased. Further, emergetic ternary diagrams are drawn to facilitate the comparison between SUT and various technologies. The resources-use efficiency of wind energy and SUT, 200 MW is found to be the lowest among all energy technologies presented in this research. Scenario analysis is performed to explore the future optimization directions. The results demonstrate that the development direction of SUT systems should mainly focus on reducing the materials demanded by the manufacturing and construction of its solar collectors. This study aims to demonstrate the value of emergy as a powerful instrument for drawing long-term sustainable strategies in energy markets for a greener tomorrow.