Electrical Energy Price Research Articles

Two alternative robust optimization models for flexible power management of electric vehicles in distribution networks

This paper presents a robust optimization problem of the flexible bidirectional power management of a smart distribution network and harmonic compensation of nonlinear loads using electric vehicles (EVs) equipped with bidirectional chargers. The base deterministic model of the proposed problem is as mixed-integer nonlinear programming (MINLP), having the objective function to minimize the economic and technical indices subject to harmonic load flow equations, EVs constraints, system operation and harmonic indices limits. This model is converted to a mixed-integer linear programming (MILP) model in the next step. In the proposed MILP model, the active, reactive and apparent loads, electrical energy, reactive power and harmonic current prices, as well as EVs characteristics, are considered uncertain parameters. Accordingly, two alternative robust optimization approaches have been implemented for the conditions of having both the probability distribution function or the bounded uncertainty in the proposed MILP problem model. The proposed model is tested on distribution networks to demonstrate its efficiency and performance. The results show that the MINLP model can be substituted by the proposed high-speed MILP model. In addition, the capacity of the injecting power of EVs is reduced in the worst-case scenario with respect to the scenario that is used in the deterministic model, while the consumed power of loads and EVs and energy price increases in this scenario. Finally, the payment of EV owners is reduced by considering EVs power and harmonic control.

A PV installation framework concerning electricity variable rates

ABSTRACTThis paper assesses building integrated photovoltaic (BIPV) installation parameters based on the profit generated by a photovoltaic system. It takes into consideration a home building case study and it investigates its monthly energy demand based on a specific location and a typical occupancy. The capability of a photovoltaic (PV) system to generate more profit occurs when solar intensity is maximum while the electric energy price is at its highest rate. The paper traces a framework that encompasses different aspects such as energy demand, energy price, and solar intensity. This framework identifies profit alternatives according to different installation parameters. A tool that predicts a PV installation hourly electric energy production is developed. The profit generated is simulated for home buildings located in Beirut (Lebanon) and Xihua (China), both at 33.8° latitude north. The paper highlights a new approach for BIPV installations, taking into account weather conditions, energy demand, and electric energy utility rates.

A two-layer decentralized approach to the optimal energy management of a building district with a shared thermal storage

We propose a decentralized scheme for the energy management of a district composed of multiple buildings. Each building is equipped with its own chiller, whereas a single thermal storage is shared among all buildings. The buildings aim at jointly minimizing the electric energy costs while guaranteeing comfort conditions for their occupants, and they can act on their own temperature set-point and the usage of the common storage to this purpose. The problem can be formulated as a constrained optimization program where the buildings decision variables are coupled via some global constraints, due to the shared storage, and the cost function, since the electric energy price depends on the district demand. To distribute the computational load and reduce the amount of transmitted information, we propose a two-layer solution where a central entity takes care of the global constraints by updating some dual variables (outer layer), whereas the primal variables, i.e., zone temperature set-point and storage usage, are optimized locally by the buildings through nested iterations where the price is recomputed based on the updated information on the district demand provided by the central entity (inner layer).

Tariff Rate for Electrical Thermal Storage for Heating, Ventilation, and Air Conditioning Systems

Background. The most efficient use of available electricity capacity during the hours of consumption decline is very important problem in Ukraine. This article provides an analysis of the actual tariff policy and the use of electricity during the hours of the low tariff for heating, ventilation and air conditioning systems. Objective. The aim of the paper is to analyze the set validity periods of the reduced prices for electrical energy. Priority attention is paid to the tariff policy differences for the cost of electricity in Ukraine and abroad and how these differences affect possible storage system cost and, thus, payback period. Methods. The general feasibility of using electricity as the heat source is presented, different energy sources as a generator of heat are compared, the possibility of strengthening cooperation between producers and consumers of electricity in order to achieve optimal modes of generation and consumption of heat is stated, the tariff plans for electricity in Ukraine and abroad are provided. Results. As a result of the work it was made the comparison of tariff policy in Ukraine and three other countries: the UK, Canada and Spain. It is shown that overseas tariff rates are more flexible than in Ukraine, and promotes more effective relationships between the power generating companies and consumers in both economic and technological aspects. It was also shown that additional day charging can significantly reduce a necessary amount of heat storage material as well as the set power of the system. Conclusions. At the current level of technological development, the actual policy for determining electricity tariffs should be based on innovative technologies, for example, on the dynamic determination of the electricity cost. It becomes relevant with the growth of the share of renewable energy sources in general electricity generation.

Optimal design and integration of a cryogenic Air Separation Unit (ASU) with Liquefied Natural Gas (LNG) as heat sink, thermodynamic and economic analyses

LNG regasification terminals are the final destination of LNG carriers. This is where the liquefied natural gas is returned to the gaseous state and fed into transmission and distribution grids. While regasification process, cryogenic LNG has a great potential for cold energy recovery. This cold energy can be used in various applications such as power generation, material freezing and sea water desalination. In this study, we used the mentioned cold energy for cryogenic air separation unit to improve the performance of this cycle. Some of the most important results of this integration are 8.04% reduction in the amount of power requirement and also 17.05% reduction in initial capital cost of ASU plant. In this paper, the required LNG flow rate for applied integration was 24.43% of ASU cycle generated oxygen flow rate. Annualized cost of system was chosen as an economic approach. A year reduction of system period of return in relation to the before integration of ASU cycle with LNG, was the most important economic result of this integration. Sensitivity analysis was done on the system economic parameters (electrical energy, oxygen and nitrogen price). The results show that the considered integration will have a more positive impact on the system period of return in higher prices of electrical energy and also in lower prices of oxygen in the market.

Análisis de los fundamentales del precio de la energía eléctrica: evidencia empírica para Colombia

Análisis de los fundamentales del precio de la energía eléctrica: evidencia empírica para Colombia

Modeling prices of wholesale market of electric energy and power by the example of the UPS of the Ural

The article oversees forecasting model for deviations of the balancing market index and day-ahead market index according to the maximum similarity sample for different levels of approximation in the context of positive and negative time-series value. The model was being tested on the factual data of the Integrated Power system of the Ural, Wholesale market for electricity and power of Russian Federation. Describes the price formation on the day-ahead market and the balancing market index. The necessity to use accurate forecasting methods consumption and prices of electrical energy and power to reduce penalties when the electric power industry entities on the energy exchange. The testing of mathematical models to predict the balancing market index deviations and day-ahead market based on a sample of maximum similarity with certain approximation equations for positive and negative values gave the prediction error of 3.3%.

ANÁLISE DA VIABILIDADE ECONÔMICA DO PROCESSO DE PIRÓLISE PARA TRATAMENTO DE RESÍDUOS SÓLIDOS URBANOS: ESTUDO DE CASO APLICADO A UMA CIDADE DE MÉDIO PORTE

Find new solutions for the treatment of municipal solid waste is a challenge of modern society. The fast pyrolysis process arises as an alternative, besides generating by-products of commercial value. The general objective of this work is to evaluate the economic viability of the pyrolysis process for treatment of municipal solid waste (MSW) applied to a medium-sized town. To meet the overall objective were determined specific objectives who understood the locational alternatives study and methods of investment analysis provided certainty, uncertainty, and risk analysis. The pyrolysis process for MSW was attractive due to high operating costs and taxes on the sale of electricity and fertilizer. The Net present value-NPV resulting cash flow is negative and there is no return on capital invested, for both the enterprise and the investor's cash flow. In this case, the research has enabled the study of vario us scenarios for economic viability of the project through sensitivity analysis. Considering the possibility of integration with more municipalities to supplement the volume of raw material, reducing the cost of transport of MSW pyrolysis plant and even th e increase in the price of electrical energy for sale, or tax exemption, the project is a cost effective alternative, while in addition to the economic benefits, the pyrolysis plant enables the Elimination of environmental liabilities generated by landfill s.

An optimal energy co-scheduling framework for smart buildings

The Heating, Ventilation and Air Conditioning (HVAC) system accounts for nearly half of the energy consumption of a typical building. Additionally, the need for HVAC changes over hours and days as does the electric energy price. Level of comfort of the building occupants is, however, a primary concern, which tends to overwrite pricing. Dynamic HVAC control under a dynamic energy pricing model while meeting an acceptable level of occupants' comfort is thus critical to achieve energy efficiency in buildings in a sustainable manner. Finally, there is the possibility that the building is equipped with some renewable sources of power such as solar panels mounted on the rooftop. The presence of Hybrid Electrical Energy Storage (HEES) system in a target building would enable peak power shaving by adopting a suitable charging and discharging schedule for each Electrical Energy Storage (EES) element, while simultaneously meeting building energy efficiency and user comfort requirements. Achieving this goal requires detailed information (or predictions) about the amount of local power generation from the renewable source plus the power consumption load of the building.This paper addresses the co-scheduling problem of HVAC control and HEES system management to achieve energy-efficient smart buildings, while also accounting for the degradation of the battery state-of-health during charging and discharging operations (which in turn determines the amortized cost of owning and utilizing a battery storage system). A time-of-use dynamic pricing scenario is assumed and various energy loss components are considered, including power dissipation in the power conversion circuitry, the rate capacity effect in the batteries, and the self-discharge in the super-capacitor. A global optimization framework targeting the entire billing cycle is presented and an adaptive co-scheduling algorithm is provided to dynamically update the optimal HVAC air flow control and the HEES system management in each time slot during the billing cycle to mitigate the prediction error of unknown parameters. Experimental results show that the proposed algorithm achieves up to 10% in the total electric utility cost compared with some baseline methods.

Deregulation of Electricity Market and Drivers of Demand for Electrical Energy in Industry

Abstract This paper investigates deregulation of electricity market focusing on electricity prices and drivers of demand for electrical energy in industry in Slovenia. The patterns in evolution of real electricity price developments and the three main components of the electricity price are calculated: liberalized market share for purchased electricity price, regulated infrastructure share for use of electricity network grids and mandatory state charges in the sale of electricity (duty, excise duty and value-added tax). To calculate the real value of electricity prices, producer price index of industrial commodities for electricity prices in industry is used as deflator and implicit deflator of gross domestic product for the size of the economy. In the empirical econometric part is used regression analysis for the amount electricity consumption in the industry depending on the real gross domestic product, direct and cross-price elasticity for natural gas prices in the industry. The results confirmed volatility in real electricity price developments with their increasing tendency and the increasing share of different taxes and state charges in the electricity prices for industry. Demand for electrical energy in industry is positively associated with gross domestic product and price of natural gas as substitute for electrical energy in industry use, and negatively associated with prices of electrical energy for industry.

Integration of Air to Water Heat Pumps into Industrial District Heating Substations

The paper aims to evaluate a potential of integration of air to water heat pumps in existing district heating substations, especially for supply of heat in an industrial sector. Facts and data from the literary search support the idea that the air source heat pumps (ASHP) should be more often used as a supplementary source of heat in district heating substations. Heat pump is fully integrated in the system and thus efficient for the industrial practice only if the actual return on investment (ROI) is positive. The ROI depends especially on investment cost, average COP, on prices of electrical energy and on the price of heat from district heating. The paper presents a case study of effective integration of 25 kW ASHP into an industrial district heating substation. Sensitivity analysis is conducted to study all the above mentioned aspects of the integration.

Decades of Disconnect: Proper Pricing Is Important [In My View

Examines the proper pricing of electrical energy that incorporates future expenses. Using marginal pricing ignores future expenses and constant expenses. Pricing without including all expenses is offering “tidbits today to offset the megatons of tomorrow’s profits.”

A fuzzy clustering approach to a demand response model

This paper proposes a novel demand response model using a fuzzy subtractive cluster approach. The model development provides support to domestic consumer decisions on controllable loads management, considering consumers’ consumption needs and the appropriate load shape or rescheduling in order to achieve possible economic benefits. The model based on fuzzy subtractive clustering method considers clusters of domestic consumption covering an adequate consumption range. Analysis of different scenarios is presented considering available electric power and electric energy prices. Simulation results are presented and conclusions of the proposed demand response model are discussed.

El servicio de energía eléctrica, un análisis a nivel nacional y provincial

Se analiza la evolución de la producción, demanda, cobertura, pérdida y precios de la energía eléctrica a nivel nacional y en Tungurahua durante el periodo 2011-2014, utilizando datos de: EEASA, Agencia de Regulación y Control de Electricidad – ARCONEL, Consejo Nacional de Electricidad – CONELEC y Sistema Nacional de Información - SNI. URL: http://revistas.uta.edu.ec/erevista/index.php/bcoyu/article/view/580

REVITALISASI INVESTASI PENGEMBANGAN ENERGI PANAS BUMI DI INDONESIA

Premises as a country that is being build, requiring electrical energy very much. It is therefore necessary for the utilization of various sources of insufficiency. During this energy from fossil sources dominate the national energy needs. But this fossil energy sources will eventually run out. So that the necessary renewable energy, among other things of geothermal energy. This energy is in addition to friendly neighborhood also has a reserve that very much. Recorded 26 percent of world geothermal energy in Indonesia. However, until recently the development of new geothermal energy range from 4 percent The main obstacle is the issue of investment is still limited, as well as policy and institutional reforms to increase investment. It is therefore necessary to revitalize geothermal energy investments through several fiscal and non fiscal incentives in the form of investment attraction such as the selling price of electricity energy geothermal interest. Current selling price of geothermal electrical energy for U.S. $ 0.97. This needs to be re-evaluated, in order to attract investors in geothermal development in Indonesia.

Price model of electrical energy for PSE applications

The electrical energy (EE) price plays a significant role in the economic assessment of industrial processes. PSE/CAPE applications are often based on economic evaluations/optimizations where EE price and its possible dynamic evolution are important input data. Planning, scheduling, on-line optimization (dynamic) conceptual design, and feasibility studies are some of the applications where short-, medium-, and long-term predictions of EE quotations are involved. The paper discusses the main issues that contribute to EE quotations such as geographical, meteorological, seasonal, political, social, and financial terms. EE prices show a significant dependency on crude oil quotations with a time-delay of about a quarter/season. An econometric model comprising both linear and periodic components with an implicit stochastic term delivered by the reference component is first commented, then identified, and finally validated respect to real EE quotations. The paper provides also a discussion on how to forecast EE prices ranging from short- to long-term horizons.

Techno economic and environmental assessment of using gasification process in order to mitigate the emission in the available steam power cycle

As a result of the gas pressure drop in natural grid pipelines in the cold seasons, the feedstock of steam power plant is changed from the natural gas into the heavy fuel oil. Sometimes this change happens for the whole winter and causes lots of environmental problems for the cities near the big power plant. Gasification is a technologically advanced and environmentally friendly process of disposing the heavy fuel oil and the coal by converting them into the usable gas products named Syngas which mainly consists of CO and H2. In this article, the feasibility study of gasification process application in the available steam power plant is considered. The 1000 MW steam power cycle is simulated and the natural gas, heavy oil, and generated syngas from gasification process of heavy fuel oil are selected as the feedstock. Results of economic analysis illustrate that in current economic conditions, the application of gasification process is not feasible in the available steam power cycle. It also shows that in the higher market prices of electrical energy, the revenue of system is much more than the emission penalty cost. So the difference between two types of calculation (considering emission penalty cost) is not noticeable.

Algorithm for Optimum Sizing of a Photovoltaic Water Pumping System

Algorithm for Optimum Sizing of a Photovoltaic Water Pumping System

A Model for Wind Turbines Placement Within a Distribution Network Acquisition Market

This paper proposes an innovative exhaustive search method for the optimal placement of wind turbines (WTs) in electrical distribution systems taking into account wind speed and load demand uncertainty, and the variability of electrical energy prices within a distribution network operator (DNO) acquisition market environment. The method combines Monte Carlo simulation (MCS) and market-based optimal power flow (OPF) to maximize the net present value (NPV) related to the investment made by WTs' developers over a planning horizon. In particular, the MCS data feed the market-based OPF problem with inter-temporal constraints in order to find the most convenient WTs allocation and priority on the network, based on distribution-locational marginal prices (D-LMPs) in a competitive electricity market. The effectiveness of the proposed method is demonstrated with an 84-bus 11.4-kV radial distribution system.

Optimization of the various modes of flexible operation for post-combustion CO2 capture plant

One option to mitigate the adverse effect of power plant output loss from adding a CO2 capture plant is to operate it in flexible modes in which the capture level and/or regeneration rate are dynamically varied in response to varying electricity market demand and price. This can help the plant meet peak electricity demand and improve its overall profit. However, the benefit is offset by higher capital costs and/or CO2 emission penalty. Various modes of flexible operation including capture level reduction and solvent storage have been optimized for a given post-combustion capture system with typical daily electrical energy price patterns and the results are compared with those from a fixed point operation. Effects of varying storage capacities and energy price patterns have also been evaluated. Simultaneous use of the two flexible modes is also optimized and the result showed significantly higher cost savings compared to the individual uses.