scholarly journals Environmental Impacts of a Solar Dish Coupled With a Micro-Gas Turbine for Power Generation

2021 ◽  
Vol 9 ◽  
Author(s):  
A. Agostini ◽  
C. Carbone ◽  
M. Lanchi ◽  
A. Miliozzi ◽  
M. Misceo ◽  
...  

Concentrated solar power (CSP) systems are regarded as a renewable energy source technology that can contribute to decoupling the energy mix from fossil fuel combustion and related environmental impacts. However, current small-scale CSP technologies (e.g., Dish-Stirling) have not entered the market yet due to high costs, complexity, and poor reliability. The EU-funded OMSoP (Optimised Microturbine Solar Power) project aimed at solving the small-scale CSP shortcomings by coupling a solar dish with the consolidated and relatively cheap technology of the micro gas turbine (MGT). In this study, an environmental life cycle assessment analysis of the production and operation of a CSP-MGT system is performed following an eco-design approach, thus identifying the environmental hotspots and how the system can be improved in terms of environmental impacts. The results of the analysis, per unit of electricity produced, were compared to other renewable technologies with the same level of dispatchability to better evaluate strengths and weaknesses of the system under exam. With regard to climate change, the greenhouse gas (GHG) emissions of the CSP-MGT system resulted in the same range as those generated by photovoltaic systems. However, the system can substantially be optimized and the GHG emissions per kWh can be reduced up to 73% with respect to the built prototype. The GHG emissions are much lower than the current Italian energy mix (by up to 94%). To reduce the environmental burden of CSP-MGT plants, the system design here considered should be revised by improving the component’s performance and significantly reducing the reflective surface and therefore the structural materials for the dish foundation and frame. The replacement of steel in the dish frame with aluminum increases all the environmental impact parameters and primary energy demand (17%–27% depending on the environmental category considered) but slightly reduces abiotic element depletion (by 9%).

Author(s):  
Sergio Mario Camporeale ◽  
Patrizia Domenica Ciliberti ◽  
Bernardo Fortunato ◽  
Marco Torresi ◽  
Antonio Marco Pantaleo

Small scale Combined Heat and Power (CHP) plants present lower electric efficiency in comparison to large scale ones, and this is particularly true when biomass fuels are used. In most cases, the use of both heat and electricity to serve on site energy demand is a key issue to achieve acceptable global energy efficiency and investment profitability. However, the heat demand follows a typical daily and seasonal pattern and is influenced by climatic conditions, in particular in the case of residential and tertiary end users. During low heat demand periods, a lot of heat produced by the CHP plant is discharged. In order to increase the electric conversion efficiency of small scale micro turbine for heat and power cogeneration, a bottoming ORC system can be coupled to the cycle, however this option reduces the temperature and quantity of cogenerated heat available to the load. In this perspective, the paper presents the results of a thermo-economic analysis of small scale CHP plants composed by a micro gas turbine (MGT) and a bottoming Organic Rankine Cycle (ORC), serving a typical residential energy demand. For the topping cycle three different configurations are examined: 1) a simple recuperative micro gas turbine fuelled by natural gas (NG), 2) a dual fuel EFGT cycle, fuelled by biomass and natural gas (50% energy input) (DF) and 3) an externally fired gas turbine (EFGT) with direct combustion of biomass (B). The bottoming cycle is a simple saturated Rankine cycle with regeneration and no superheating. The ORC cycle and the fluid selection are optimized on the basis of the available exhaust gas temperature at the turbine exit. The research assesses the influence of the thermal energy demand typology (residential demand with cold, mild and hot climate conditions) and CHP plant operational strategies (baseload vs heat driven vs electricity driven operation mode) on the global energy efficiency and profitability of the following three configurations: A) MGT with cogeneration; B) MGT+ ORC without cogeneration; C) MGT+ORC with cogeneration. In all cases, a back-up boiler is assumed to match the heat demand of the load (fed by natural gas or biomass). The research explores the profitability of bottoming ORC in view of the following tradeoffs: (i) lower energy conversion efficiency and higher investment cost of high biomass input rate with respect to natural gas; (ii) higher efficiency but higher costs and reduced heat available for cogeneration in the bottoming ORC; (ii) higher primary energy savings and revenues from feed-in tariff available for biomass electricity fed into the grid.


2020 ◽  
Vol 12 (24) ◽  
pp. 10602
Author(s):  
Huilong Lin ◽  
Yanfei Pu ◽  
Xueni Ma ◽  
Yue Wang ◽  
Charles Nyandwi ◽  
...  

“Introducing grass into fields”, the major approach to modern grassland agriculture, is the crucial direction of agricultural structure adjustment in the farming-pastoral zone of Northern China. However, there have been few studies on the environmental impacts of agricultural production in this pattern. We used the life cycle assessment (LCA) method for the first time from the perspective of the entire industry chain from agricultural material production to livestock marketing, which involves the combination of planting and breeding. A comparative analysis of the environmental impact processes of beef and pork, the main products of the two existing agricultural systems in Eastern Gansu, was conducted. The findings showed that based on the production capacity of the 1 ha land system, the comprehensive environmental impact benefit of the grassland agricultural system (GAS) in the farming-pastoral zone was 21.82%, higher than that of the cultivated land agricultural system (CLAS). On Primary energy demand (PED) and environmental acidification potential (AP), the GAS needs improvement because those values were 38.66% and 22.01% higher than those of the CLAS, respectively; on global warming potential (GWP), eutrophication potential (EP), and water use (WU), the GAS performed more environment-friendlily because those values were 25.00%, 68.37%, and 11.88% lower than those of the CLAS, respectively. This indicates that a change in land use will lead to a change in environmental impacts. Therefore, PED and AP should be focused on the progress of grassland agriculture modernization by “introducing grass into fields” and new agricultural technologies.


Author(s):  
Sergio Mario Camporeale ◽  
Patrizia Domenica Ciliberti ◽  
Bernardo Fortunato ◽  
Marco Torresi ◽  
Antonio Marco Pantaleo

Small-scale combined heat and power (CHP) plants present lower electric efficiency in comparison to large scale ones, and this is particularly true when biomass fuels are used. In most cases, the use of both heat and electricity to serve on-site energy demand is a key issue to achieve acceptable global energy efficiency and investment profitability. However, the heat demand follows a typical daily and seasonal pattern and is influenced by climatic conditions, in particular in the case of residential and tertiary end users. During low heat demand periods, a lot of heat produced by the CHP plant is discharged. In order to increase the electric conversion efficiency of small-scale micro-gas turbine for heat and power cogeneration, a bottoming organic Rankine cycle (ORC) system can be coupled to the cycle, however, this option reduces the temperature and the amount of cogenerated heat available to the thermal load. In this perspective, the paper presents the results of a thermo-economic analysis of small-scale CHP plants composed of a micro-gas turbine (MGT) and a bottoming ORC, serving a typical residential energy demand. For the topping cycle, three different configurations are examined: (1) a simple recuperative micro-gas turbine fueled by natural gas (NG); (2) a dual fuel externally fired gas turbine (EFGT) cycle, fueled by biomass and natural gas (50% share of energy input) (DF); and (3) an externally fired gas turbine (EFGT) with direct combustion of biomass (B). The bottoming ORC is a simple saturated cycle with regeneration and no superheating. The ORC cycle and the fluid selection are optimized on the basis of the available exhaust gas temperature at the turbine exit. The research assesses the influence of the thermal energy demand typology (residential demand with cold, mild, and hot climate conditions) and CHP plant operational strategies (baseload versus heat-driven versus electricity-driven operation mode) on the global energy efficiency and profitability of the following three configurations: (A) MGT with cogeneration; (B) MGT+ ORC without cogeneration; and (C) MGT+ORC with cogeneration. In all cases, a back-up boiler is assumed to match the heat demand of the load (fed by natural gas or biomass). The research explores the profitability of bottoming ORC in view of the following trade-offs: (i) lower energy conversion efficiency and higher investment cost of biomass input with respect to natural gas; (ii) higher efficiency but higher costs and reduced heat available for cogeneration with the bottoming ORC; and (iii) higher primary energy savings and revenues from feed-in tariff available for biomass electricity fed into the grid.


2021 ◽  
Vol 3 (4) ◽  
pp. 699-710
Author(s):  
Sarat Chandra Togarcheti ◽  
Ramesh Babu Padamati

The present study aims at comparing the life cycle environmental impacts of polyunsaturated fatty acids production (PUFA) from microalgae and farmed fish. PUFA production from microalgae cultivated via heterotrophy and photoautotrophy was assessed and compared. The primary energy demand (PED) and environmental impacts (EI) of PUFA production from microalgae via heterotrophy were significantly lower compared to PUFA produced via photoautotrophy. Furthermore, PED and EI of PUFA production from fish farmed in marine net pens were assessed. The results indicated that the PED and EI of PUFA production from farmed fish are higher than that produced from microalgae cultivated via heterotrophy. Therefore, the results suggest that PUFA produced from microalgae via heterotrophy could substitute fish oil from an environmental perspective. Furthermore, life cycle analysis results indicate that PUFA derived from microalgae could potentially replace fish oil in the fish feed, thus reducing the pressure on oceans.


Energy Policy ◽  
2012 ◽  
Vol 42 ◽  
pp. 329-340 ◽  
Author(s):  
Shiwei Yu ◽  
Yi-Ming Wei ◽  
Ke Wang

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Junli Shi ◽  
Junyu Hu ◽  
Mingyang Ma ◽  
Huaizhi Wang

Purpose The purpose of this paper is to present a method for the environmental impact analysis of machine-tool cutting, which enables the detailed analysis of inventory data on resource consumption and waste emissions, as well as the quantitative evaluation of environmental impact. Design/methodology/approach The proposed environmental impact analysis method is based on the life cycle assessment (LCA) methodology. In this method, the system boundary of the cutting unit is first defined, and inventory data on energy and material consumptions are analyzed. Subsequently, through classification, five important environmental impact categories are proposed, namely, primary energy demand, global warming potential, acidification potential, eutrophication potential and photochemical ozone creation potential. Finally, the environmental impact results are obtained through characterization and normalization. Findings This method is applied on a case study involving a machine-tool turning unit. Results show that primary energy demand and global warming potential exert the serious environmental impact in the turning unit. Suggestions for improving the environmental performance of the machine-tool turning are proposed. Originality/value The environmental impact analysis method is applicable to different machine tools and cutting-unit processes. Moreover, it can guide and support the development of green manufacturing by machinery manufacturers.


2018 ◽  
Vol 192 ◽  
pp. 790-800 ◽  
Author(s):  
Heiko Dunkelberg ◽  
Johannes Wagner ◽  
Conrad Hannen ◽  
B. Alexander Schlüter ◽  
Long Phan ◽  
...  

2011 ◽  
Vol 133 (01) ◽  
pp. 24-29 ◽  
Author(s):  
John Reilly ◽  
Allison Crimmins

This article predicts future global energy demand under a business-as-usual scenario. According to the MIT projections, conventional technology supported by fossil fuels will continue to dominate under a business-as-usual scenario. In fact, in the absence of climate policies that would impact energy prices, fossil fuels will supply nearly 80% of global primary energy demand in 2100. Alternative energy technologies will expand rapidly. Non-fossil fuel use will grow from 13% to 20% by 2100, with renewable electricity production expanding nearly tenfold and nuclear energy increasing by a factor of 8.5. However, those sources currently provide such a small share of the world's energy that even rapid growth is not enough to significantly displace fossil fuels. In spite of the growth in renewables, the projections indicate that coal will remain among the least expensive fuel sources. Non-fossil fuel alternatives, such as renewable energy and nuclear energy, will be between 40% and 80% more expensive than coal.


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