Abstract-The high average solar radiation in Indonesia makes solar power plant an option to improve renewable energy-based electricity generation in the country. Currently in Indonesia, the photovoltaic (PV) plant has been more widely implemented, and several extensive researches on solar thermal plant have been carried out. In this paper, a comparative study on the 20-MW on-grid solar thermal and photovoltaic (PV) power plant is committed to measure the cost competitiveness of the technologies in Rongkop district, Indonesia; which is recently considered as the center for solar power plant in Indonesia. The simulation follows two installed energy capacity scenarios by the International Energy Agency and is committed up to year 2030, in accordance with the target year of United Nations' Sustainable Development Goals.By using System Advisor Model it is shown that a 20-MW solar thermal power plant equipped with 6-hour storage is able to produce slightly higher annual energy output than the solar PV plant design of similar capacity. However, the levelized cost of electricity (LCOE) values of both solar thermal plants with no storage and 6-hour storage significantly exceed the LCOE of PV plant throughout the years of simulation. This implies that in Rongkop, Indonesia the PV plant is a more economically competitive solar power plant technology to be implemented until 2030, compared to the solar thermal plant.