A thermo-economic optimization model of an integrated solar combined-cycle (ISCC) has been developed to evaluate the performance of an existing combined-cycle gas turbine (CCGT) plant when retrofitted with solar trough collectors. The model employs evolutionary algorithms to assess the optimal performance and cost of the power plant. To define the trade-offs required for maximizing gains and minimizing costs (and to identify ‘optimal’ hybridization schemes), two conflicting objectives were considered, namely, minimum required investment and maximum net present value (NPV). Optimization was performed for various feed-in tariff (FIT) regimes, with tariff levels that were either fixed or that varied with electricity pool prices. It was found that for the given combined-cycle power plant design, only small annual solar shares (∼1.2% annual share, 4% of installed capacity) could be achieved by retrofitting. The integrated solar combined-cycle design has optimal thermal storage capacities that are several times smaller than those of the corresponding solar-only design. Even with strong incentives to shift the load to periods in which the prices are higher, investment in storage capacity was not promoted. Nevertheless, the levelized costs of the additional solar-generated electricity are as low as 10 c€/kWh, compared to the 17–19 c€/kWh achieved for a reference, nonhybridized, “solar-only” concentrating solar power plant optimized with the same tools and cost dataset. The main reasons for the lower cost of the integrated solar combined-cycle power plant are improved solar-to-electric efficiency and the lower level of required investment in the steam cycle. The retrofitting of combined-cycle gas turbine plants to integrated solar combined-cycle plants with parabolic troughs represents a viable option to achieve relatively low-cost capacity expansion and strong knowledge building regarding concentrating solar power.
Thermo-Economic Optimization of Hybridization Options for Solar Retrofitting of Combined-Cycle Power Plants
Contributed by the Solar Energy Division of ASME for publication in the Journal of Solar Energy Engineering. Manuscript received April 13, 2012; final manuscript received March 5, 2013; published online August 21, 2013. Assoc. Editor: Markus Eck.
- Views Icon Views
- Share Icon Share
- Cite Icon Cite
- Search Site
Pihl, E., Spelling, J., and Johnsson, F. (August 21, 2013). "Thermo-Economic Optimization of Hybridization Options for Solar Retrofitting of Combined-Cycle Power Plants." ASME. J. Sol. Energy Eng. May 2014; 136(2): 021001. https://doi.org/10.1115/1.4024922
Download citation file:
- Ris (Zotero)
- Reference Manager