Productivity and costs of slash bundling in Nordic conditions

The number of slash bundlers and the volume of slash bundling have been rapidly increasing during the last few years in Finland. However, no comprehensive time or follow-up studies have been carried out on slash bundling technology in Finland or in any other country. Metsäteho Oy carried out studies on the productivity and costs of slash bundling in different Nordic recovering conditions. The study methods included both time and follow-up studies. Data were collected during the summer and winter period primarily in Norway spruce (Picea abies L. Karst.) dominated clear cutting sites. The bundling techniques performed by different types of bundler (Fiberpac 370, Timberjack 1490D, Pika RS 2000, Valmet WoodPac) were studied.

The average productivity of slash bundling was 18.1 bundles per operating (E₁₅, including delays shorter than 15 min) hour with the Timberjack 1490D and Fiberpac 370 bundlers in the follow-up study. The operator of the slash bundler had the greatest effect on the productivity of bundling. The prerequisite for increased bundling volumes is a reduction in the costs of the most expensive sub-stage of the bundling supply chain, i.e. bundling itself. This requires improved recovery conditions at bundling sites, increased bundling productivity, larger sized bundles, and the execution of bundling operations in two work shifts using an efficient bundler and effective operator working methods. Implementation of these development measures will bring the bundling supply chain up to a speed that makes it the most competitive supply chain for forest chips in terms of total supply costs for long-distance transportation distances of more than 60 km.     

Short-term behavior of classical analytic solutions for the design of ground-source heat pumps

Over the years several methods have been proposed to simulate and design the earth heat exchanger for a ground-source heat pump (GSHP) system. Some of these methods are based on numerical techniques while others rely on analytic solutions. Among the latter, two classical solutions have been extensively used over the years, the infinite line source (ILS) solution and the infinite cylindrical source (ICS). These solutions were known to overestimate the fluid temperature when the time scale is important and are valid only in a time range between a minimum and a maximum value which are often adequate for must design applications. It is usually accepted that for small Fourier numbers, the ICS solution should be used instead of the ILS. This paper revisits the short-term behavior of these solutions and we arrive at different conclusions than those usually accepted in the literature if the Fourier number is based on the borehole radius, which is normally the case. The reasons for these discrepancies are discussed and several options are proposed.     

Techno-economic and environmental assessment of LNG export for hydrogen production

A critical requirement of a widely contemplated hydrogen economy is the development of a low carbon hydrogen supply chain that is cost competitive. This comprehensive techno-economic assessment demonstrates, for the first time, the viability of a complete hydrogen supply chain based on the transport of liquefied natural gas (LNG). This is demonstrated via the established LNG trade route from Australia to Japan against three key performance indicators (KPIs): delivered hydrogen cost, CO₂ emissions intensity (EI) across the entire supply chain, and technology readiness level (TRL). The hydrogen supply chain entails LNG export to Japan where it is used for blue hydrogen production; the by-product CO₂ is then liquefied and repatriated to Australia for sequestration or utilisation. Within this supply chain, various hydrogen production technologies are assessed, including steam methane reforming (SMR), autothermal reforming (ATR) and natural gas pyrolysis (NGP). SMR with carbon capture and storage (CCS) resulted in the lowest total hydrogen supply cost of 19 USD/GJ (2.3 USD/kgH2) which comfortably meets the 2030 Japanese hydrogen cost target of 25 USD/GJ (3 USD/kgH2) and is very close to the 17 USD/GJ 2050 Japanese hydrogen cost target. This technology also obtained the lowest CO₂ emission intensity (EI) of 38 kgCO2/GJ (4.5 kgCO2/kgH2); this was surprisingly lower than ATR with CCS primarily due to the emissions associated with ATR electricity provision for air separation. Future technologies and strategies are detailed so as to further reduce cost and supply chain emissions; these were shown to be able to reduce total CO2 EI to 14 kgCO2/GJ (1.6 kgCO2/kgH2). Hence this analysis indicates that this supply chain can act to significantly reduce CO2 emissions whilst uniquely meeting targeted hydrogen supply costs up to 2050. As such it is proposed here as an eminently viable hydrogen export option deploying both existing technology and capacity, at least until other hydrogen supply chain vectors (such as liquid hydrogen and ammonia) derived from green hydrogen production become competitive across all the KPIs.     

Sustainability of hydrogen supply chain. Part I: Identification of critical criteria and cause–effect analysis for enhancing the sustainability using DEMATEL

The enhancement of sustainability of hydrogen supply chain is of vital importance for the stakeholders/decision-makers to design a sustainable hydrogen supply chain. The objective of this paper is to develop a method for prioritizing the influential factors, identifying the key driving factors that influence the sustainability of hydrogen supply chain and mapping the cause–effect relationships to improve the sustainability of hydrogen supply chain. In this paper, thirty seven criteria in four aspects including economic, technological, environmental and societal aspects are considered for enhancing the sustainability of hydrogen supply chain, and decision making trial and evaluation laboratory has been used to analyze the relationships among these criteria. The status of hydrogen supply chain in China has been studied by the proposed method, and the results are consistent with the actual conditions. It could be concluded that the proposed method is feasible and could be popularized to some other cases.     

RDEA: A recursive DEA based algorithm for the optimal design of biomass supply chain networks

The optimal design of supply chain networks is often examined based on one or more economic or other criteria (e.g., cost, profit environmental impact, danger, time). However, the efficiency of the derived solutions is often ignored. In this work, a recursive DEA (RDEA) algorithm is presented, which introduces a different way of designing a supply chain network. The selection of possible installed facilities is based on minimum cost and maximum efficiency, through a MILP model. Optimal supply chain structure is obtained when the termination criterion is met, yielding only the efficient solutions, while simultaneously reducing the overall cost. An application of this RDEA algorithm to a biomass supply chain is examined. A comparative study is also presented, demonstrating the results obtained when solving the MILP without the proposed algorithm and with the use of an RDEA.     

基于状态序列的分段开关及主变备自投调试方法研究

备用电源自动投入装置的传统调试方法要求多人配合,且无法严格校验电流、电压、动作时间整定值,不符合继电保护调试标准化作业要求。为此,分析了湖北省电网变电站分段开关及主变备自投方式,将其动作过程状态序列化,提出了基于状态序列的分段开关及主变备自投调试方法。备自投装置调试实例表明,所提方法正确有效,可准确校验动作逻辑及整定值,克服了传统调试方法的不足,更加严谨、高效,对备自投装置调试工作的标准化具有指导意义。     

Logistical supply chain design for bioeconomy applications

This paper proposes and tests novel supply chain designs for bioenergy and biobased products that result in logistical costs savings of 2–38%. The proposed supply chain design reduces the costs of: (1) purchasing logistical harvesting equipment; (2) operating logistical harvesting equipment; and (3) holding feedstock inventory, by using a multitude of crop types as feedstock, instead of just one, as is common in research and practice today. In so doing, this research challenges the prevalent assumption that monocultures, despite their known environmental concerns, are preferable from a costs perspective. Simulation/optimization is used to test supply chain designs, and then to find the environmental conditions where these new supply chain designs could be most profitably implemented.     

Supply chain network design and operation: Systematic decision-making for centralized,distributed, and mobile biofuel production using mixed integer linear programming (MILP) under uncertainty

Biomass resources are dispersed and subject to seasonal and geographical uncertainties. Therefore, supply chain network design and management can significantly influence the economic viability of a biofuel technology. Fast pyrolysis offers several advantages for biofuel production. It is a relatively cheap process and can be conducted in centralized, decentralizes, or even mobile configurations. Furthermore, it does not overlap with the human food supply chain, using wastes or lignocellulosic feedstocks. In this article, a mixed integer (piece-wise) linear program (MILP) was developed to determine the optimal supply chain design and operation, under uncertainty. Rigorous process modelling and detailed economic analysis were coupled with exhaustive search of potential production locations and biomass resources in order to enhance the fidelity of the solution. The optimisation results suggest that a combination of geographically centralized pyrolysis and upgrading centres would suffice for supply chain management under deterministic conditions. However, under uncertain scenarios, it is advantageous to deploy mobile pyrolyzers to add extra flexibility to the process operation. Further analysis suggested that as the mobile pyrolyzers are commercialized and their unit price is reduced, this technology has the potential to become a key member of the biofuel supply chain.     

Risk and sustainability analysis of complex hydrogen infrastructures

Building a network of hydrogen refuelling stations is essential to develop the hydrogen economy within transport. Additional, hydrogen is regarded a likely key component to store and convert back excess electrical power to secure future energy supply and to improve the quality of biomass-based fuels. Therefore, future hydrogen supply and distribution chains will have to address several objectives. Such a complexity is a challenge for risk assessment and risk management of these chains because of the increasing interactions. Improved methods are needed to assess the supply chain as a whole. The method of “Functional modelling” is discussed in this paper. It will be shown how it could be a basis for other decision support methods for comprehensive risk and sustainability assessments.     

Towards a more efficient energy use in photovoltaic powered products

This paper analyzes the energy saving and power management solutions necessary to improve the energy consumption efficiency in photovoltaic powered products. Important in the design of such products is not only the energy supply optimization required to deliver the actual energy to fulfil their function, but also efficient energy transfer along the energy chain. In this paper, several methods to improve the efficiency of the energy chain are described. This includes an analysis of optimization methods for photovoltaic powered products, its functional system and product use.     

Modelling and control of hydrogen and energy flows in a network of green hydrogen refuelling stations powered by mixed renewable energy systems

The planning of a hydrogen infrastructure with production facilities, distribution chains, and refuelling stations is a hard task. Difficulties may rise essentially in the choice of the optimal configurations. An innovative design of hydrogen network has been proposed in this paper. It consists of a network of green hydrogen refuelling stations (GHRSs) and several production nodes. The proposed model has been formulated as a mathematical programming, where the main decisions are the selection of GHRSs that are powered by the production nodes based on distance and population density criteria, as well the energy and hydrogen flows exchanged among the system components from the production nodes to the demand points. The approaches and methodologies developed can be taken as a support to decision makers, stakeholders and local authorities in the implementation of new hydrogen infrastructures. Optimal configurations have been reported taking into account the presence of an additional hydrogen industrial market demand and a connection with the electrical network. The main challenge that has been treated within the paper is the technical feasibility of the hydrogen supply chain, that is mainly driven by uncertain, but clean solar and wind energy resources. Using a Northern Italian case study, the clean hydrogen produced can be technically considered feasible to supply a network of hydrogen refuelling stations. Results show that the demands are satisfied for each time period and for the market penetration scenarios adopted.     

基于供应链的现代煤炭物流体系构建研究

煤炭是中国经济发展所需的最重要能源,煤炭物流在占据中国物流较大比重的同时,存在着市场混乱、成本高、第三方物流企业少、煤炭供应链不完整等问题。设计了三级网链状结构的现代煤炭物流供应链体系,提出了建立配套煤炭集运体系、仓储配送体系以及信息服务体系,培育专业第三方物流企业,解决铁路运输瓶颈等举措。     

Planning sustainable hydrogen supply chain infrastructure with uncertain demand

This study introduces a multi-period optimization model taking into account the stochasticity and the effect of uncertainty in the hydrogen production, storage and usage in macro view (e.g. county level). The objective function includes minimization of total daily social cost of the hydrogen supply chain network with uncertain demand. There are several factors and key attributes, which influence consumer choice to buy a fuel cell vehicle. At the same time, consumer preference on the demand side is the most important factor in predicting changes in the auto market. A spatially aggregated demand model was developed to estimate the potential demand for fuel cell vehicles based on different household attributes such as income, education etc. These models were applied to evaluate the future hydrogen supply chain for State of New Jersey.     

Heat treatment of carbon-based powders carrying platinum alloy catalysts for oxygen reduction: influence on corrosion resistance and particle size

The influence of heat treatment of carbon-based powders carrying platinum and platinum-iron binary alloy catalysts for oxygen reduction is investigated. The catalysts powders are subjected to heating at various temperatures for a certain time. An accelerated ageing test (AAT) is used to evaluate the corrosion resistance and sintering resistance of each catalyst. The dissolution of the catalyst in the AAT filtrate is analysed with a spectrophotometer and provides a measure of the corrosion resistance. The particle size of catalyst powders before and after AAT is determined by X-ray diffraction and indicates the sintering resistance. Transmission electron microscopy and electron diffraction techniques are also employed as supplementary testing methods. So-called ‘anchor effects’ are proposed to explain the enhanced effect of iron in platinum-iron binary catalysts compared with catalysts that contain platinum alone.     

Review of modern methods and technologies for using of solar energy in the operation of anaerobic digestion systems

The article presents various methods and technologies for using of solar energy in anaerobic bioconversion systems. Various methods of convertion of solar radiation are consistently considered – from its direct use to photovoltaic, thermal, photovoltaic thermal and concentrating. Schemes for introducing solar energy converters into anaerobic bioconversion systems, as well as various solar radiation converters for heat and electricity supply of anaerobic bioconversion systems, are proposed. As power generating components in the article also discusses photovoltaic modules with an extended rated power period, photovoltaic thermal roofing panels with a two-component polysiloxane compound, thermal and photovoltaic thermal solar roofing panels, air-cooled photovoltaic thermal siding panel and concentrator solar photovoltaic thermal module with high-voltage matrix photovoltaic converters. The proposed schemes of systems and design of solar modules will ensure a reduction in the use of thermal energy from the produced gas for power supply for the own needs of anaerobic bioconversion systems, which will make them cheaper and more efficient in operation.     

Stored energy control for long-term continuous operation of an electric and hydrogen hybrid energy storage system for emergency power supply and solar power fluctuation compensation

In order to realize a large-capacity stand-alone emergency power supply that enables highly reliable and high-quality power supply at the time of a large-scale natural disaster and enables effective use of solar power generation, we proposed an electric and hydrogen hybrid energy storage system (HESS). It is composed of an electric double-layer capacitor bank, fuel cell, electrolyzer, and hydrogen storage (buffer gas tank and metal hydride). In an emergency, this HESS is expected to supply power for loads together with photovoltaics panels for a long time. In usual time, it should not only cooperate with external electricity grids to convert unstable photovoltaic output power into reliable power supply, but also maintain sufficient stored energy in case of emergency. To realize the continuous operation of the HESS in both emergency and usual time, we proposed an electric double-layer capacitor's state-of-charge feedback control method and a hydrogen energy feedback control method, coordinating an energy management method based on Kalman filter algorithm. An experiment and a simulation demonstrated the operations of a 10-kW scale model HESS in emergency and usual time mode, respectively. The demonstrations verified the correct performance of the proposed HESS with the proposed control methods and enabled the continuous operation of the HESS.     

Integrated planning method of green hydrogen supply chain for hydrogen fuel cell vehicles

To satisfy the growing refueling demand of hydrogen fuel cell vehicles (HFCVs) with carbon-free hydrogen supply, this paper proposes an integrated planning method of green hydrogen supply chain. First, the k-shorted path method is introduced to analyze HFCV refueling load considering vehicle travel habits and routing diversity. Second, based on it, a two-stage integrated planning model is established to minimize the total investment and operation cost. The construction of hydrogen refueling stations, electrolysis-based hydrogen generation stations and hydrogen pipelines are coordinated with their operating constraints, constituting the green hydrogen supply chain, in which hydrogen storage is also an important part for consideration to address variable renewable power. Then, the proposed model is reformulated as a mixed integer linear programing (MILP) problem solved efficiently. Finally, the case studies are carried out on an urban area in Xi'an China to verify the validity and correctness of the proposed method. The results show that the integrated planning can realize synergy benefits. The influence of electricity prices and k values is also discussed.     

船舶温室气体减排对主机的影响分析

介绍了航运业温室气体排放现状,以及针对脱碳目标的主要减排措施:技术性减排措施、营运性减排措施及基于市场的减排措施。分析了以上各类减排措施对船舶主机的影响。在综合分析IMO船舶温室气体减排法规及相关减排技术对我国船舶主机、相关零部件技术发展,供应链建设以及复合型人才培养等方面的影响的基础上提出了发展建议。     

Supply chain cost analysis of long-distance transportation of energy wood in Finland

The increasing use of bioenergy has resulted in a growing demand for long-distance transportation of energy wood. For both biofuels and traditional forest products, the importance of energy efficiency and rail use is growing. A GIS-based model for energy wood supply chains was created and used to simulate the costs for several supply chains in a study area in eastern Finland. Cost curves of ten supply chains for logging residues and full trees based on roadside, terminal and end-facility chipping were analyzed. The average procurement costs from forest to roadside storage were included. Railway transportation was compared to the most commonly used truck transportation options in long-distance transport. The potential for the development of supply chains was analyzed using a sensitivity analysis of 11 modified supply chain scenarios.For distances shorter than 60 km, truck transportation of loose residues and end-facility comminution was the most cost-competitive chain. Over longer distances, roadside chipping with chip truck transportation was the most cost-efficient option. When the transportation distance went from 135 to 165 km, depending on the fuel source, train-based transportation offered the lowest costs. The most cost-competitive alternative for long-distance transport included a combination of roadside chipping, truck transportation to the terminal and train transportation to the plant. Due to the low payload, the energy wood bundle chain with train transportation was not cost-competitive. Reduction of maximum truck weight increased the relative competitiveness of loose residue chains and train-based transportation, while reduction of fuel moisture increased competitiveness, especially of chip trucks.     

Electric load forecasting by using dynamic neural network

Electrical energy is fundamental for the wellbeing and for the economic development of any country. However, all countries must ensure access to essential resources and ensure the continuity of its supply. Due to the non-storable nature of electrical energy, the amount of consumed active power should always be equal the produced active power just to avoid power system frequency deviation problem. In order to keep the relationship production–consumption relation in compliance with different standards and to secure profitable operations of power system, electric load consumption must be predicted and controlled instantaneously. Several statistical and classical techniques are proposed in the literature but unfortunately all these methods are not accurate in a satisfactory manner. In this paper, a dynamic neural network is used for the prediction of daily power consumption. The suitability and the performance of the proposed approach is illustrated and verified with simulations on load data collected from French Transmission System Operator (RTE) website. The obtained results show that the accuracy and the efficiency are improved comparatively to conventional methods widely used in this field of research.