Techno-enviro-economic evaluation of hybrid organic Rankine-thermoelectric generators integrated waste steam heat recovery systems for power generation

Abstract

Abstract This study compares two integrated configurations for recovering low-grade waste heat using an Organic Rankine Cycle (ORC) and Thermoelectric Generators (TEG). The waste heat source is a water–vapor mixture that exits the steam turbine before entering the condenser in a steam power plant. In Configuration 1, the heat passes through the ORC before reaching the TEG system. Configuration 2 uses the reverse order. A comprehensive techno-enviro-economic analysis is conducted under varying steam inlet qualities, mass flow rates, and TEG arrangements. A detailed MATLAB-based model is developed to simulate both systems. Results show that higher steam quality and flow rates increase system performance. Configuration 1 produces a slightly higher peak power of 984 kW with 7% efficiency. Configuration 2 reaches 934.9 kW and 6.97% efficiency. The best performance is achieved with a longitudinal TEG alignment (12 × 833). Configuration 1 also recovers up to 97.53% of input heat. In contrast, Configuration 2 starts with 2.51% recovery through TEGs. Economic analysis confirms that Configuration 1 is more cost-effective, achieving the lowest Levelized Cost of Electricity (LCOE) ($0.02205/kWh), a 44.9% reduction from local tariffs in Egypt. It also shows profitability within six years and over $1.15 million in profit after 20 years. Environmentally, the system reduces CO₂ emissions by 525.83 tons annually, earning $21,033.23 in carbon credits. These findings highlight Configuration 1 as the optimal solution. It balances energy recovery, cost savings, and environmental impact, supporting sustainable development goals SDG 7 (Clean Energy) and SDG 13 (Climate Action).