This study focuses on designing a solar thermal system utilizing parabolic trough collectors to replace conventional heat requirements in industrial processes. The research also assesses the impact of implementing this system on reducing CO2 emissions and provides economic analysis for industrial cities from two geographically different islands in Indonesia: Java and Sulawesi. This study uses a parabolic trough collector to absorb energy from sunlight. Based on the calculation of the energy balance of the solar collector, the average heat absorbed by the collector is 545.5 kJ m−2 h−1 in Java and 606.5 kJ m−2 h−1 in Sulawesi. As a result, approximately 67.55 tonnes of CO2 per day will be mitigated by transitioning from conventional processes. The economic analysis indicates a payback period of 3.54 years, a net present value of 1.4 million USD, and an internal rate of return of 12 % based on fuel savings.