Academic literature on the topic 'Gemasolar power plant'

This work presents the characteristics of a solar thermal tower power plant in two different places (Seville and Dubai) using three different HTFs (NaNO3-KNO3, KCl-MgCl2 and Li2CO3-Na2CO3-K2CO3) and three different power cycles (Rankine, sCO2 Recompression and sCO2 Partial cooling cycles). An indirect configuration is considered for the Gemasolar power plant. Detailed modelling is carried out for the conversion of incident power on the heliostat to the output electricity. Optimization of the cycle is carried out to determine the most promising cycle configuration for efficiency. The results showed that for the Gemasolar power plant configuration, the performance of the KCl-MgCl2 based plant was poorest amongst all. NaNO3-KNO3 based plant has shown good performance with the Rankine cycle but plant having Li2CO3-Na2CO3-K2CO3 as HTF was best for all three cycles. Partial cooling was the best performing cycle at both locations with all three HTFs. Placing the Seville Plant in Dubai has improved the efficiency from 23.56% to 24.33%, a capacity factor improvement of 21 and 52 GW additional power is generated. The optimization of the plant in Dubai has shown further improvements. The efficiency is improved, the Capacity factor is increased by 31.2 and 77.8 GW of additional electricity is produced.

Concerns over the environmental influence of greenhouse gas (GHG) emissions have encouraged researchers to develop alternative power technologies. Among the most promising, environmentally friendly power technologies for large-scale applications are solar power tower plants. The implementation of this technology calls for practical modeling and simulation tools to both size the plant and investigate the scale effect on its economic indices. This paper proposes a methodology to design the main components of solar power tower plants and to estimate the specific investment costs and the economic indices. The design approach used in this study was successfully validated through a comparison with the design data of two operational commercial power tower plants; namely, Gemasolar (medium-scale plant of 19.9 MWe) and Crescent Dunes (large-scale plant of 110 MWe). The average uncertainty in the design of a fully operational power tower plant is 8.75%. A cost estimation showed the strong influence of the size of the plant on the investment costs, as well as on the economic indices, including payback period, internal rate of return, total life charge costs, and levelized cost of electricity. As an illustrative example, the methodology was applied to design six solar power tower plants in the range of 10–100 MWe for integration into mining processes in Chile. The results show that the levelized cost of electricity decreases from 156 USD/MWhe for the case of a 10-MWe plant to 131 USD/MWhe for the case of a 100-MWe plant. The internal rate of return of plants included in the analyses ranges from 0.77% (for the 10-MWe case) to 2.37% (for 100-MWe case). Consequently, the simple payback ranges from 16 years (for the 100-MWe case) to 19 years (for the 10-MWe case). The sensitivity analysis shows that the size of the solar receiver heavily depends on the allowable heat flux. The degradation rate and the discount rate have a strong influence on economic indices. In addition, both the operation and the deprecation period, as well as the price of electricity, have a crucial impact on the viability of a solar power tower plant. The proposed methodology has great potential to provide key information for prospective analyses for the implementation of power tower technologies to satisfy clean energy needs under a wide range of conditions.

This report focuses on addressing the electricity shortfall in Pakistan with the help of renewable resources. At present, the country is facing a shortfall of almost 7,000 megawatts (MW) which is affecting every walk of life and causing almost 1.5 to 2% GDP loss on annual basis. Previous research done on this subject reveals that electricity demand has always remained high then the total generation capacity of Pakistan. Similarly, it has been pointed out that the country is not taking maximum benefit from its available hydro, solar and wind resources. This leads us to the basic purpose of this research which is to have an exploratory understanding of the strategies adopted by India, China, Brazil and Spain for electricity generation in a green fashion and how can these strategies be implemented  in Pakistan. Case study has been adopted as methodology for this purpose. This research work also discusses the factors contributing in the lack of promotion of renewable energy resources in Pakistan and provide detailed analyses of positive changes these projects can bring in lives of masses in Pakistan. The sustainable management of surface water resource in the country has been discussed in particular as the country faced worst floods in its history during years 2010 & 2011. It will result in enhancing the surface water storage ability of Pakistan which will significantly reduce our dependence on underground water reserves and will directly increase our electricity generation capacity through hydro dams. Similarly, sustainable forest management has been discussed at length as it will not only ensure environmental sustainability but will also result in increase availability of biomass. Not to mention the fact that wood biomass is much cheaper then conventional source of electricity generation provided it is obtained through sustainable forest management. Finally, if all the green strategies discussed in this research work will be implemented, it will increase the overall electricity generation capacity of Pakistan up to 9% respectively.

Due to their relatively high capital and environmental cost of two-tank molten salt thermal storage systems, a significant amount of research has gone into looking for sensible and latent thermal energy storage alternatives suitable for concentrated solar thermal (CST) plants. Despite a large number of developments in the last decade, comparative studies among promising options have been lacking. In particular, only a few comparative studies are available in which thermal energy storage (TES) systems are integrated as an active subcomponent of CST plant. Therefore, this study compares selected sensible heat thermal energy storage systems based on their integrated performance with other CST components (e.g. a tower -based CST plant with a Rankine cycle) over a year of operation. In the present study, annual performances of single-medium thermocline (SMT), double-medium thermocline (DMT), and shell-and-tube (ST) system were compared with that of a conventional two-tank molten salt storage system. Concrete with porosity of 0.2 (concrete occupies 80% of the system) was selected as a low cost filler material in the DMT and ST systems. The systems were sized for 15 hours of storage capacity and integrated into a validated 19.9 MWe Gemasolar power plant model with solar multiple of 2.5. Before performing annual integrated simulations, an optimum design of each storage system was selected based on a performance analysis of the storage system over a constant 15 hours discharge. A CST plant with a two-tank molten salt system enables the highest amount of electricity generation in a year followed by the SMT and DMT systems, which resulted in 7% and 9% less electricity generation, respectively. For the CST plant with ST system, 20% less electricity was generated over a year. Overall, this study provides a methodology for the comparison of the TES alternatives, and it gives insight the most promising alternative for replacing two-tank molten salt systems.

The performance of the tower based concentrated solar thermal (CST-tower) plant is very sensitive to the operation strategy of the plant and the incident heat flux on the receiver. To date, most studies have been examined only the design mode characteristics of the cavity receivers, but this paper significantly expands the literature by considering non-design operating conditions of this important sub-component of the CST-tower plants. A feasible non-design operating conditions of the cavity receivers that was considered in this study is the storage mode of operation. Two practical dynamic control strategies were examined then to find the most efficient approach: fixed solar field mass flowrate (Approach “A”) and fixed outlet temperature at receiver (Approach “B”). To evaluate the performance of the cavity receiver, a thermal model is developed to be used for design and non-design analysis. The thermal model has been then validated against available data from the Gemasolar operating solar Tower plant. In non-design conditions, the effects of heat transfer fluid (solar salt) temperature and flowrate are mainly evaluated in terms of the non-dimensional receiver thermal output, non-dimensional power output, receiver energetic efficiency, receiver surface temperature, receiver outlet temperature, and the fraction of solar field usage. The results of this study (e.g. off design receiver efficiency correlations) assist researchers to evaluate cavity receivers without performing detail simulations. They also help investigators to choose an appropriate control strategy and to analyze the viability of other CST-tower subcomponents that have thermal interactions with the receiver (e.g. dynamic control of the phase change storage unit or its boundary conditions).