Exergy-Based Analysis and Optimization of an Integrated Solar Combined-Cycle Power Plant

Area of Science:

• Energy Systems Engineering
• Renewable Energy Integration
• Thermodynamics and Exergy Analysis

Background:

• Renewable energy transition is slow in developing nations due to reliance on low-cost fossil fuels.
• Integration of conventional power plants with concentrated solar power (CSP) can accelerate sustainable energy production.
• Combined-cycle power plants (CCPPs) offer efficiency advantages for baseload power generation.

Purpose of the Study:

• To propose, evaluate, and optimize a novel natural gas-fired integrated solar combined-cycle (ISCC) power plant.
• To assess the system's performance using exergy-based methods for both day and night operations.
• To determine the economic viability and identify cost reduction strategies for the proposed ISCC plant.

Main Methods:

• Development of a natural gas-fired ISCC system combining CCPP, direct steam generation, and linear Fresnel collectors.
• Exergy analysis to evaluate thermodynamic efficiencies during day and night cycles.
• Economic and exergoeconomic analyses to determine the levelized cost of electricity (LCOE) and optimize component costs.
• Iterative exergoeconomic optimization for performance enhancement and cost reduction.

Main Results:

• The proposed ISCC plant achieves exergetic efficiencies of 50.7% (day) and 58.1% (night).
• A weighted average LCOE of $40.0/MWh was initially identified, reduced to $39.2/MWh after optimization.
• The optimized system demonstrates a specific investment cost of $1088/kW and a 17% solar share.

Conclusions:

• The novel natural gas-fired ISCC plant is a competitive and viable option for sustainable baseload power.
• Exergy-based optimization significantly improves efficiency and reduces electricity costs.
• The system facilitates higher renewable energy integration, particularly in regions with fossil fuel resources.