Prototype for the harvesting of cultivated herbaceous energy crops,an economic and technical evaluation

The scope of this study was to evaluate a multi-purpose prototype, the biotriturator, for the harvesting of biomass species cultivated in Northern Italy that would allow the baling of biomass to reduce the handling and storage costs. Harvesting trials were conducted on two herbaceous perennials: giant reed (Arundo donax L.) and switchgrass (Panicum virgatum L.), plus a herbaceous annual fiber sorghum (Sorghum bicolor L. Moench).A technical and economic evaluation compared three harvesting systems in which the biomass was shredded with the biotriturator. The first system was a cutting-shredding-baling in the same operation. The second required two successive steps, the first was cutting and shredding with the biotriturator, the second was baling. The third harvesting system required three successive steps: cutting and shredding with the biotriturator, windrowing with star wheel rakes and baling. While the first and second systems were evaluated on the two perennial crops the third was evaluated on an annual crop.Considering the hectares that can be covered by the biotriturator (170 ha of sorghum and 270 of switchgrass, with an average annual use of 200 h) and the total harvest cost (9.9–12.1 € Mg⁻¹ dry biomass), the harvesting system represents an effective solution for situations like that in Italy, where average farm sizes are small.     

Characteristics and compositional change in round and square switchgrass bales stored in South Central Oklahoma

Storage studies were conducted in 2009 and 2010 on large round (1.83 m × 1.53 m) and square (1.22 m × 1.22 m × 2.44 m) switchgrass bales stored for 6 months. Round and square bales were stored outside under different conditions: tarped (on pallets, gravel and ground) and untarped (on pallets, gravel and ground). Round and square bales were also stored inside and served as a control treatment. During both years, outside tarped bales resisted moisture accumulation and thus dry matter losses were equivalent to bales stored inside. The average dry matter loss for the round and square bales stored inside was 0.6% compared to 0.9 and 2.8% for the tarped round and square bales stored outside, respectively. However, untarped round (11.3%) and square (32.7%) bales on an average had greater dry matter loss than the tarped round (0.9%) and square (2.8%) bales. The untarped square bales consistently had higher moisture contents than untarped round bales which resulted in greater dry matter loss in untarped square bales. Hemicellulose content was more severely affected than cellulose content during storage. In 2010, untarped square bales stored on gravel, ground and pallets lost 30%, 24% and 16% of hemicellulose content, respectively.     

Technical and economic evaluation of solar hydrogen production by supercritical water gasification of biomass in China

A novel thermochemical method for solar hydrogen production was proposed by state key laboratory of multiphase flow in power engineering (SKLMFPE) of Xi’an Jiaotong University. In this paper, a technical and economic evaluation of the new solar hydrogen production technology was conducted. Firstly, the advantages of this new solar hydrogen production process, compared with other processes, were assessed and thermodynamic analysis of the new process was carried out. The results show that biomass gasification in supercritical water driven by concentrating solar energy may be used to achieve high efficiency solar thermal decomposition of water and biomass for hydrogen production. Secondly, the hydrogen production cost was analyzed using the method of the total annual revenue requirement. The estimated hydrogen production cost was 38.46RMB/kg for the experimental demonstration system with a treatment capacity of 1 ton wet biomass per hour, and it would be decreased to 25.1 RMB/kg if the treatment capacity of wet biomass increased from 1 t/h to 10 t/h. A sensitivity analysis was also performed and influence of parameters on the hydrogen production cost was studied. The results from technical and economic evaluation show that supercritical water gasification of biomass driven by concentrated solar energy is a promising technology for hydrogen production and it is competitive compared to other solar hydrogen production technologies.     

Study on key parameters design and economic evaluation of the electric heating and solid sensible heat thermal storage device

电制热固体储热系统对可再生能源消纳、能源清洁化利用具有重要意义。电制热固体储热装置的关键参数设计以及经济性分析是提高经济效益的重要手段。因此,本文提出了电制热固体储热装置投资运行费用计算方法。通过对比不同供暖方式所需费用分析了电制热固体储热装置的经济性。同时研究了谷电利用系数对电制热固体储热装置经济性的影响。最后,采用案例分析验证本文所提经济性评估方法的合理性与正确性。本文的研究内容为用户对电制热固体储热装置的选择提供参考。     

Assessment of the wind power potential at SANAE IV base, Antarctica: a technical and economic feasibility study

This paper presents a study for the utilization of wind energy at the South African research station, SANAE IV, in Antarctica (71°40’ S 2° 50’ W). A procedure to evaluate the feasibility of utilising wind power for Antarctic stations is given. The analysis is based on the technical and economic aspects of installing and operating a wind turbine at remote locations. Special attention has been given to conditions encountered at Antarctica, like site accessibility, low temperatures, icing and snow, long transportation distances and environmental issues. The aspect of externalities is incorporated into the economic analysis. The Northern Power Systems NW100/19 wind turbine is found to be the best-suited wind turbine for use at SANAE IV, given the harsh climatic conditions, like frequent windstorms and extreme temperatures. The wind turbine features a yearly energy output of 430 MWh with a capacity factor of 0.49, at a mean wind speed of 10.8 m/s. The study shows that a wind turbine installation at SANAE IV is an attractive solution to reduce fuel consumption and therefore emissions of the diesel electric generators considerably. The use of a wind turbine at SANAE IV could lead to a savings in externalities of about R110 000, -per annum.     

Economic and environmental evaluation of transporting imported pellet: A case study

This work compares the different methods of transport used to import pellets, through a case study of pellets imported into Italy. The objective was to evaluate the economic and environmental sustainability of the different transport methods, the former via a cost analysis, and the latter via an LCA analysis. In particular, the method of transport by sea from Virginia (USA) was compared to overland transport from some European locations. Industrial pellet markets strictly depend on the import of wood pellets from outside the EU-27. The analysis of transport phase is therefore crucial, for inspecting the consequences of transporting such a commodity along considerable distances and allowing decision makers to make strategic decisions about trade planning, optimize international routes, and choose the most sustainable transport methods. The economic analysis showed that road transport cost ranged from 18 to 112 € t⁻¹, while sea cost from 68 to 82 € t⁻¹. Concerning the environmental evaluation, the impact categories most involved were Fossil Fuels, Respiratory Inorganics and Land Use, showing that the critical points in the transport phase are the oil consumption per km and the production of high quantities of SO₂ and NO_x. Basically, transport by sea appeared to be better, from the economic viewpoint, and for what concerns one of the major environmental impacts involved (fossil fuels) and primary energy consumption, compared to road transport from some of the European locations normally supplying the Italian market. On the contrary, road transport was preferred if transporting pellets from locations nearest to Italy.     

Capacity assessment and cost analysis of geologic storage of hydrogen: A case study in Intermountain-West Region USA

Hydrogen is an integral component of the current energy transition roadmap to decarbonize the economy and create an environmentally-sustainable future. However, surface storage options (e.g., tanks) do not provide the required capacity or durability to deploy a regional or nationwide hydrogen economy. In this study, we have analyzed the techno-economic feasibility of the geologic storage of hydrogen in depleted gas reservoirs, salt caverns, and saline aquifers in the Intermountain-West (I-WEST) region. We have identified the most favorable candidate sites for hydrogen storage and estimated the volumetric storage capacity. Our results show that the geologic storage of hydrogen can provide at least 72% of total energy consumption of the I-WEST region in 2020. We also calculated the capital and levelized costs of each storage option. We found that a depleted gas reservoir is the most cost-effective candidate among the three geologic storage options. Interestingly, the cushion gas type plays a significant role in the storage cost when we consider hydrogen storage in saline aquifers. The levelized costs of hydrogen storage in depleted gas reservoirs, salt caverns, and saline aquifers with large-scale storage capacity are approximately $1.15, $2.50, and $3.27 per kg of H₂, respectively. This work provides essential guidance for the geologic hydrogen storage in the I-WEST region.     

An experimental and numerical investigation of heat transfer during technical grade paraffin melting and solidification in a shell-and-tube latent thermal energy storage unit

The latent thermal energy storage system of the shell-and-tube type during charging and discharging has been analysed in this paper. An experimental and numerical investigation of transient forced convective heat transfer between the heat transfer fluid (HTF) with moderate Prandtl numbers and the tube wall, heat conduction through the wall and solid–liquid phase change of the phase change material (PCM), based on the enthalpy formulation, has been presented. A fully implicit two-dimensional control volume Fortran computer code, with algorithm for non-isothermal phase transition, has been developed for the solution of the corresponding mathematical model. The comparison between numerical predictions and experimental data shows good agreement for both paraffin non-isothermal melting and isothermal solidification. In order to provide guidelines for system performance and design optimisation, unsteady temperature distributions of the HTF, tube wall and the PCM have been obtained by a series of numerical calculations for various HTF working conditions and various geometric parameters, and the thermal behaviour of the latent thermal energy storage unit during charging and discharging has been simulated.     

An overview of the environmental,economic, and material developments of the solar and wind sources coupled with the energy storage systems

There is a constant growth in energy consumption and consequently energy generation around the world. During the recent decades, renewable energy sources took heed of scientists and policy makers as a remedy for substituting traditional sources. Wind and photovoltaic (PV) are the least reliable sources because of their dependence on wind speed and irradiance and therefore their intermittent nature. Energy storage systems are usually coupled with these sources to increase the reliability of the hybrid system. Environmental effects are one of the biggest concerns associated with the renewable energy sources. This study summarizes the last and most important environmental and economic analysis of a grid‐connected hybrid network consisting of wind turbine, PV panels, and energy storage systems. Focusing on environmental aspects, this paper reviews land efficiency, shaded analysis of wind turbines and PV panels, greenhouse gas emission, wastes of wind turbine and PV panels' components, fossil fuel consumption, wildlife, sensitive ecosystems, health benefits, and so on. A cost analysis of the energy generated by a hybrid system has been discussed. Furthermore, this study reviews the latest technologies for materials that have been used for solar PV manufacturing. This paper can help to make a right decision considering all aspects of installing a hybrid system. Copyright © 2017 John Wiley & Sons, Ltd.     

Hydrogen production from swine manure biogas via steam reforming of methane (SRM) and water gas shift (WGS): A ecological,technical, and economic analysis

Inadequate management of swine manure can lead to contamination of watercourses, groundwater, soil, and air, representing a risk to the sustainability and expansion of pig farming as an economic activity. The aim of this study was to evaluate the potential of this waste for the production of hydrogen from swine manure biogas through steam reforming and water gas shift processes. In this study, calculations of ecological, exergetic and economic efficiencies were carried out. The ecological efficiency, pollution indicator and energy efficiency of the process were, respectively, 93.73%, 19.15 and 79.06%, showing the viability from an ecological standpoint. This is an 8-year plant payback with a hydrogen production cost of $0.14/kWh, in a production scenario of 8760 h/year, showing an exergetic efficiency of 76%. The results from these analyses demonstrates that this type of hydrogen production is an attractive economic route. The results from these analyses have shown that this hydrogen production technology has great economic potential and presents high exegetic yield.     

Clustering assisted artificial neural network for handling noisy big data: An application for estimation of parameter in combined mode conduction and radiation heat transfer

A pattern net assisted mapping artificial neural network (PAMANN) model for estimation of parameters in problem with large data (1300 × 121 matrix size) is reported. A pattern net-based multilayer perceptron neural network (MLPNN) model for clustering the data, followed by mapping MLPNN model for mapping the target with the input, is developed as PAMANN model. A heat transfer problem with combined mode conduction and radiation in porous medium is solved numerically, and is called direct model. In the inverse model, a PAMANN model is developed by using data generated through the direct model. The PAMANN model is able to estimate two parameters (extinction coefficient β and convective coupling P₂) after taking temperature profile as input. The model is tested for different number of neurons in hidden layer, and different levels of noise in input data. Twelve different algorithms are explored in training of mapping MLPNN, and compared for performance. Levenberg–Marquardt algorithm is found to estimate the parameters with high accuracy, but took high CPU time. Bayesian regularization is found to consume very high CPU time with moderate accuracy in estimation of parameters. Variations in hidden layer neuron number and noise in input data, were done to analyze the performance of mapping MLPNN with different training algorithms. Algorithms O-Step Secant, conjugate gradient with Polak-Ribiére updates, and conjugate gradient with Fletcher-Reeves updates are able to handle all variations of noise and number of neurons in hidden layer, with good accuracy of estimation and low CPU time consumption. Under high computational resource LM algorithm can be used for all cases. Up to 0.99132 value of regression coefficient is obtained in mapping MLPNN model with 15 hidden neurons, indicating the high accuracy of the model. With the help of PAMANN model, highly accurate (absolute error 1.78%) estimation of parameters is obtained. The model can handle upto 1% noise in input data, while giving accurate results.