Integration of direct air capture with solar tower and chimney power plants: energy, economic and carbon assessments

[Geoengineering News]

https://www.sciencedirect.com/science/article/abs/pii/S0038092X26003440

Authors: Youssef Elaouzy, Mustapha Soukri, Kumar Patchigolla, Abdulkarem I. Amhamed, Abdelghafour Zaabout

27 April 2026

https://doi.org/10.1016/j.solener.2026.114656

Highlights

•An integrated system, consisting of a DAC system, a STPP, and a SCPP, is assessed.

•Nine scenarios with different waste heat recovery and heat supply configurations are considered.

•Electricity costs of the integrated system drop by up to 35% versus a conventional STPP.

•Up to 316 ktCO2e/year is avoided by the integrated system with a STPP of 123 MWe.

•Use of heat pumps and STPP low-pressure steam for CO2 desorption is promising.

Abstract

The integration of concentrating solar power and direct air capture (DAC) systems remains limited by the high energy penalty, intermittency, and the lack of efficient system-level designs for waste heat utilization and cost reduction. This study evaluates the energy, economic, and carbon performance of an integrated system in which a DAC unit is installed between the towers of a solar tower power plant (STPP) and a solar chimney power plant (SCPP). This system aims to leverage the STPP waste heat to reduce DAC energy penalty, enhance SCPP electricity generation, and capture substantial amounts of CO2. The feasibility of the system is analyzed under nine scenarios involving different waste heat recovery and supply configurations for CO2 desorption and power generation. Furthermore, sensitivity analyses are performed, exploring the impact of key technical and economic parameters on overall performance. The integrated system reduces the electricity production costs by up to 35% compared to a conventional STPP, while further reductions in electricity costs can be achieved through lower interest rates, reduced capital and operating expenditures, and higher carbon taxes. Environmentally, the integrated system achieves a net CO2 avoidance of up to 316 ktCO2e/year for a STPP of 123 MWe. Across all scenarios, harnessing the STPP condensation-based waste heat recovery combined with heat pumps or using STPP’s low-pressure steam for CO2 desorption provides the most promising pathways for low-energy and cost-effective CO2 capture. These configurations open new opportunities for simultaneous electricity generation and carbon removal with reduced energy and cost burdens.

Source: ScienceDirect