scholarly journals Evaluation of Energy Efficiency and the Reduction of Atmospheric Emissions by Generating Electricity from a Solar Thermal Power Generation Plant

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 645
Author(s):  
Gary Ampuño ◽  
Juan Lata-Garcia ◽  
Francisco Jurado

The increase of renewable energy generation to change the productivity of a country and electrify isolated sectors are some of the priorities that several governments have imposed in the medium term. Research centers are looking for new technologies to optimize the use of renewable energies and incorporate them into hybrid generation systems. In the present work, the modeling of a solar thermal energy generation plant is being carried out. The climatic data used belong to two coastal cities and one island of Ecuador. The contribution of this work is to simulate a complete model of SCF and PCS, in which the variables of outlet temperature and oil flow are involved at the same time. Previously investigations use only outlet temperature for evaluating power plants. The model of the solar thermal plant is composed of a field of solar collectors, a storage tank, and an energy conversion system. As a result, we obtain a model of a thermosolar plant that will allow us to make decisions when considering the incorporation of micronetworks in systems isolated from the electrical network. The use of thermosolar technology allows the reduction in the risk of spills by the transport of fossil fuels in ships. The study of the CO2 emission factor in Ecuador from 2011 to 2018 is also carried out.

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Hui Hong ◽  
Hongguang Jin ◽  
Jun Sui ◽  
Jun Ji

Solar thermochemical processes inherently included the conversion of solar thermal energy into chemical energy. In this paper, a new mechanism of upgrading the energy level of solar thermal energy at around 200°C was revealed based on the second law thermodynamics and was then experimentally proven. An expression was derived to describe the upgrading of the energy level from low-grade solar thermal energy to high-grade chemical energy. The resulting equation explicitly reveals the interrelations of energy levels between middle-temperature solar thermal energy and methanol fuel, and identifies the interactions of mean solar flux and the reactivity of methanol decomposition. The proposed mechanism was experimentally verified by using the fabricated 5kW prototype of the receiver∕reactor. The agreement between the theoretical and the experimental results proves the validity of the mechanism for upgrading the energy level of low-grade solar thermal energy by integrating clean synthetic fuel. Moreover, the application of this new middle-temperature solar∕methanol hybrid thermochemical process into a combined cycle is expected to have a net solar-to-electric efficiency of about 27.8%, which is competitive with other solar-hybrid thermal power plants using high-temperature solar thermal energy. The results obtained here indicate the possibility of utilizing solar thermal energy at around 200°C for electricity generation with high efficiency by upgrading the energy level of solar thermal energy, and provide an enhancement to solar thermal power plants with the development of this low-grade solar thermochemical technology in the near future.


Author(s):  
K. Bammert ◽  
A. Sutsch ◽  
M. Simon ◽  
A. Mobarak

An alternative solution for solar energy conversion to the heliostat-tower and solar farm (parabolic trough) concept is presented in the form of large parabolic dish collectors using small high temperature gas turbines for producing electricity from solar thermal energy. A cost and efficiency comparison for the different solar thermal power plants has shown that the large parabolic dish with gas turbine set is a superior system design especially in the net power range of 50 to 2000 kW. The important advantages of the large parabolic dish concept are discussed. For the important components such as the gas turbo converter, the receiver and the parabolic dish collector, design proposals for economic solutions are presented. An advanced layout for a 250-kW gas turbo converter with recuperator is presented in detail.


Author(s):  
William K. Gboney

It is estimated that within the next 40 years, solar thermal power plants would be capable of supplying more than half of the electricity needs of EUMENA. While solar irradiance differs widely in Europe due to seasonal variations, in the MENA region, there is abundant and continuous solar irradiance. This make the MENA region suitable for establishing CSP plants and exporting the electricity generated to Europe. This has driven many institutions and agencies, including the World Bank and the Desertec Foundation, to propose various schemes to promote the use of CSP systems in the MENA region. The objective of this paper is to examine the existing policy and regulatory frameworks in the MENA countries, identify any barriers and make recommendations on how to surmount these barriers, to increase the scale and scope of utilizing CSPs and other renewable energy technologies (RETs) in the region. The paper concludes by making a number of policy and regulatory recommendations to support utilization of solar thermal energy resource within the MENA region.


Author(s):  
A. Giostri ◽  
M. Binotti ◽  
P. Silva ◽  
E. Macchi ◽  
G. Manzolini

Parabolic trough can be considered the state of the art for solar thermal power plants thanks to the almost 30 years experience gained in SEGS and, recently, Nevada Solar One plants in US and Andasol plants in Spain. One of the major issues that limits the wide diffusion of this technology is the high investment cost of the solar field and, particularly, of the solar collector. For this reason, since several years research activity has been trying to develop new solutions with the aim of cost reduction. This work compares commercial Fresnel technology with conventional parabolic trough plant based on synthetic oil as heat transfer fluid at nominal conditions and evaluates yearly average performances. In both technologies, no thermal storage system is considered. In addition, for Fresnel, a Direct Steam Generation (DSG) case is investigated. Performances are calculated by a commercial code, Thermoflex®, with dedicated component to evaluate solar plant. Results will show that, at nominal conditions, Fresnel technology have an optical efficiency of 67% which is lower than 75% of parabolic trough. Calculated net electric efficiency is about 19.25%, while parabolic trough technology achieves 23.6%. In off-design conditions, the gap between Fresnel and parabolic trough increases because the former is significantly affected by high radiation incident angles. The calculated sun-to-electric annual average efficiency for Fresnel plant is 10.2%, consequence of the average optical efficiency of 38.8%, while parabolic trough achieve an overall efficiency of 16%, with an optical one of 52.7%. An additional case with Fresnel collector and synthetic oil outlines differences among investigated cases. Finally, because part of performance difference between PT and Fresnel is simple due to different definitions, additional indexes are introduced in order to make a consistent comparison.


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