Prospects for Use of Solar Thermal Energy in High-Temperature Process Heat Applications

Concentrating solar power is a family of solar energy technologies that have been used for decades to produce power. These technologies have a unique advantage, which is the ability to store thermal energy for prolonged periods of time such that stable and dispatchable energy can be provided to the electricity grid. However, concentrating solar power has been recently losing market share to photovoltaic technology due to the former’s significantly higher initial cost. There are many efforts worldwide to develop innovative solutions that reduce the cost and/or increase efficiency of concentrating solar power systems. However, concentrating solar thermal energy already has great promising area of application that is still largely unexplored, and that is high-temperature industrial process heat. This study attempts to make the case for using concentrating solar thermal energy in process heat applications by examining the economic feasibility (represented by the levelized cost of energy) for three scenarios of deployment, where the temperature levels are 400°C, 550°C, and 700°C, respectively. The first scenario uses parabolic trough collectors, while the second uses a central receiver system, both with 12 hours of molten salt storage. The third scenario uses a central receiver system that employs the innovative falling particle receiver concept to push the operating limit to 700°C, and silica sand is used to store thermal energy for 12 hours. The location chosen for this analysis is Alice Springs, Australia, due to its high direct normal irradiance and the presence of mining industries in its vicinity. The analysis shows that all three scenarios have a lower levelized cost of energy when compared to natural gas. To further confirm these findings, the analysis needs to be extended to other locations to account for different solar resources and different economic constraints.