Optimal subsidy in promoting distributed renewable energy generation based on policy benefit

Distributed renewable energy generation via micro-grid plays a strategic role in defining energy policy for mitigating the pressure of global climate changes and energy reservation. As the initial installation of the renewable generation equipment is costly, it is necessary that the government provides incentive schemes to private investors aiming at mobilizing private capital to support distributed renewable energy generation. This paper brings forward optimal subsidy to stimulate private investment and focuses more on the government’s expected policy benefit. We formulate principal–agent model in which the private investor’s preference toward renewable generation is described as asymmetric information. We analyze the optimal subsidy with the purpose of maximizing the expected policy benefit; besides, this paper reveals benefit conflicts between the policymakers and the private investors, and examines the parameters’ effect on the government’s purpose under the condition of asymmetric information. Finally, a numerical example is presented to test the effectiveness of the model. The results shed new light on the role of investor’s preference in determining the share of renewable energy generation; moreover, it has important implication for policymakers: the results suggest that radically innovative systems will get down the cost curve and may display higher long-term potentials, but in the short run, the government should eliminate asymmetric information as far as possible and improve the investors’ environment-friendly awareness.     

Optimal operation of a multibasin reservoir system

A simulation-optimization procedure is presented for evaluating the extent of interbasin transfer of water in the Peninsular Indian river system consisting of 15 reservoirs on four river basins. A system-dependent simulation model is developed incorporating the concept of reservoir zoning to facilitate releases and transfers. The simulation model generates a larger number of solutions which are then screened by the optimization model. The Box complex nonlinear programming algorithm is used for the optimization. The performance of the system is evaluated through simulation with the optimal reservoir zones with respect to four indices, reliability, resiliency, vulnerability and deficit ratio. The results indicate that by operating the system of 15 reservoirs as a single unit the existing utilization of water may be increased significantly.     

Radiation safety assessment of a system of small reactors for distributed energy

A passively safe small reactor for a distributed energy system, PSRD, is an integral type of light-water reactor with a thermal output of 100 or 300 MW aimed to be used for supplying district heat, electricity to small grids, and so on. Candidate locations for the PSRD as a distributed energy source are on-ground, deep underground, and in a seaside pit in the vicinity of the energy consumption area. Assessments of the radiation safety of a PSRD were carried out for three cases corresponding to normal operation, shutdown and a hypothetical postulated accident for several siting candidates. Results of the radiation safety assessment indicate that the PSRD design has sufficient shielding performance and capability and that the exposure to the general public is very low in the case of a hypothetical accident.     

Optimal sizing of energy storage system for microgrids

Microgrids (MGs) are Low Voltage distribution networks comprising various distributed generators (DG), storage devices and controllable loads that can operate either interconnected or isolated from the main distribution grid as a controlled entity. Energy storage system (ESS) is a vital part of an MG. In this paper, a methodology is proposed for the optimal allocation and economic analysis of ESS in MGs on the basis of net present value (NPV). As the optimal operation of an MG strongly depends on the arrangement and allocation of its ESS, economic operation strategies and optimal allocation methods of the ESS devices are required for the MG. Self-adaptive Bee Swarm Optimization (SBSO) algorithm is applied to optimize the operation strategies and capacities of ESS in MGs in order to find maximal NPV, the generation schedule of ESS and distributed generation sources. This paper is to suggest, among those available ESS, the optimal sizes and types of them and their optimal arrangement, such that the total NPV achieved during the system operational lifetime period is maximized. After introducing the methodology, a case study is presented for illustration.     

Combined design and load shifting for distributed energy system

Renewable distributed energy generation (DEG) system plays an important role in future power developments and is one of the options to reduce energy consumption. It is envisaged that energy efficiency of DEG systems can be improved via load shifting (LS). This study proposed a heuristic-based numerical approach to perform LS analysis on renewable stand-alone DEG systems. The technique is an extension from a method known as the Electric System Cascade Analysis (ESCA). The new technique, which focuses on efficient electricity utilisation is able to determine the optimal: (i) load profiles, (ii) capacity of power generator, (iii) capacity and power of energy storage (ES) and (iv) charging/discharging schedule of ES. The stage-wise technique allows user to compare and determine the optimal design in a flexible way while having a better understanding of the selection of options. The application of ESCA-LS on a case study revealed that after incorporation of direct LS (load manipulation) in addition to LS by ES (supply manipulation), the power generators and ES capacity can be further reduced. While reduction of 3.1 % for solar-PV installation area and 3.9 % for biomass power generator is recorded, ES power-related capacity and energy-related capacity managed a higher reduction of up to 19.0 and 13.2 % for the main case study     

Optimal operation of a complex thermal system: a case study

The paper focuses on the search for the optimal operation modes of a complex thermal plant. The system under analysis is basically made-up by four gas-fueled reciprocating engines with heat recovery. Each engine can drive simultaneously an electric generator as well as the compressor of a heat-pump/chiller. The plant is interconnected to the electric utility grid, both to receive additional power and to deliver power in excess. In addition, each heat-pump/chiller can be driven electrically, using the electric generator as a motor. For any given load condition, a large number of operation modes are possible. The problem of finding out the configuration that minimizes the economic cost of operating the system is dealt with. This cost is regarded as the objective function to be minimized in a typical constrained optimization problem. Statement and solution of this problem are discussed. Numerical examples are included and commented.     

An integrated computer-aided system for generation and evaluation of sustainable process alternatives

This paper presents an integrated system for generation of sustainable process alternatives with respect to new process design as well as retrofit design. The generated process alternatives are evaluated through sustainability metrics, environmental impact factors as well as inherent safety factors. The process alternatives for new process design as well as retrofit design are generated through a systematic method that is simple yet effective and is based on a recently developed path flow analysis approach. According to this approach, a set of indicators are calculated in order to pinpoint unnecessary energy and material waste costs and to identify potential design (retrofit) targets that may improve the process design (in terms of operation and cost) simultaneously with the sustainability metrics, environmental impact factors and the inherent safety factors. Only steady state design data and a database with properties of compounds, including, environmental impact factor related data and safety factor related data are needed. The integrated computer-aided system generates the necessary data if actual plant or experimental data are not available. The application of the integrated system is highlighted through a number of examples including the well-known HDA process.     

A compact system for timing and energy pulse generation

This paper describes a new kind of pulse generator, able to provide not only two pairs of coincident pulses, with continuously variable amplitude (0–5 V) for each pulse and delay (40–150 μs) between the two pairs — energy simulation — but also the corresponding timing signals — time of flight simulation — with different intrinsic variable delays ranging from 50 ps up to 128 ns, in steps of 50 ps, with a proper time resolution better than 15 ps. Some experimental results, obtained using the present device, are also reported.     

Indicators for sustainable energy development from a negentropic perspective

In this paper, the indicators for sustainable energy development derived recently by several international organizations and national teams are reviewed, in the light of a negentropic perspective related to the non-material human needs. Specifically, indicators for efficient use of mental resources and capacities (in addition to energy and material ones) are derived, an approach which is lacking in the present lists of sustainability indicators. As a result, some additional indicators concerning organizational attention deficit, occupational stress, corruption pressure and brain-drain are introduced and discussed.     

Optimal distributed generation location using mixed integer non-linear programming in hybrid electricity markets

This study presents mixed integer non-linear programming (MINLP) approach for determining optimal location and number of distributed generators in hybrid electricity market. For optimal location of distributed generation (DG), first the most appropriate zone has been identified based on real power nodal price and real power loss sensitivity index as an economic and operational criterion. After identifying the suitable zone, mixed integer non-linear programming approach has been applied to locate optimal place and number of distributed generators in the obtained zone. The non-linear optimisation approach consists of minimisation of total fuel cost of conventional and DG sources as well as minimisation of line losses in the network. The pattern of nodal real and reactive power prices, line loss reduction and fuel cost saving has been obtained. The results have also been obtained for pool electricity market model for comparison. The impact of demand variation on the results has also been obtained for both the market models. The proposed MINLP-based optimisation approach has been applied for IEEE 24 bus reliability test system.     

Nanowires for energy generation

As a result of their morphology, nanowires bring new properties and the promise of performance for a range of electronic devices. This review looks into the properties of nanowires and the multiple ways in which they have been exploited for energy generation, from photovoltaics to piezoelectric generators.     

An optimization study of a palm oil-based regional bio-energy supply chain under carbon pricing and trading policies

Biomass residues due to their low bulk density typically require frequent transportation from biomass plantations in rural areas to conversion bio-energy power plants. This issue contrasts with environmental protection strategies, especially when power plants are facing different carbon reduction policies that enforce them to emit less than a given specific carbon amount. Although several researchers have investigated bio-energy supply chains concerning environmental policies, the majority of studies have been devoted to strategic decisions over a single planning period. This paper presents a multi-period bio-energy supply chain under carbon pricing (carbon tax) and carbon trading (cap-and-trade) policies at the tactical planning level. A mixed-integer linear programming model was adopted to optimize the proposed regional oil-palm biomass-to-bio-energy supply chain planning model. The numerical results indicate that when carbon pricing is in place when carbon tax increases linearly, carbon emissions’ reductions have a nonlinear trend, whereas both cost increase and carbon emissions’ reductions have a relatively upward trend in the carbon trading scheme. This paper also presents the sensitivity analysis of the proposed model regarding cost, emissions’ generation and supply chain performance. Finally, the paper recommends several significant practical implications and policy-making insights for managers and policymakers.     

Investigation of the use of a central unique renewable energy system versus distributed units for crop irrigation

This paper discusses a comparison study of the use of 100% renewable energy systems for desert and remote areas, investigating both a central unique unit and distributed units. An initial HRES consisting of a photovoltaic (PV) array and wind generator is used to power an agricultural area of 4 ha once with a central unit and then with four distributed units. The selection of the optimal size is accomplished through linear programming based on the simplex algorithm to minimize the total life cycle cost. The results show for the first time that the use of a distributed renewable energy system containing a full PV array is cost-effective compared to a central unit.     

Costs of sustainable electricity generation

This article is based on a report commissioned by the IEE Professional Network on Engineering for a Sustainable Future. It looks at the actual present-day costs of generating electricity from all the available technologies, and also summarises the sustainability characteristics of each technology. It discusses the current situation of power in the UK, the development of new generation plant, fossil fueled power generation, hydroelectric power, nuclear power and renewable energy resources     

基于负荷预测的冰蓄冷空调系统的优化运行策略

为了在不同冷负荷下合理分配蓄冰/释冰量和制冷机组运行时间,提出一种基于负荷预测的冰蓄冷空调系统的优化运行策略,使用ELM算法建立负荷预测模型,根据该负荷预测值系统自动制定优化运行策略。将该优化运行策略应用于西安咸阳国际机场4号制冷站冰蓄冷系统,控制制冷机组运行和蓄冰装置的冷量分配。经实际运行数据对比验证,基于该模型的负荷预测值与实际运行值匹配度达到85%,应用优化运行策略之后系统运行成本降低6.11%。     

Patent fees for a sustainable EU patent system

This paper puts forward a sustainable fee structure for the EU Patent (COMPAT). The proposal includes pre-grant and post-grant fees and illustrates the differences between Euro-direct applications and PCT applications. The break-even analysis shows that the COMPAT would make the European patent system more attractive with significantly lower relative costs. At the same time, the new schedule provides a financially sustainable model for the system by preserving relatively high absolute fees and allowing for a fee reduction for small innovative firms and public research organizations.