Operating Reserve Research Articles

Análise tarifária em instalações elevatórias de água – cenários para mitigação do impacto econômico das faturas de energia elétrica

Este artigo tem por objetivo avaliar a situação econômico-operacional de uma estação elevatória de água bruta, que atende a dois grandes municípios do sul do Brasil, frente ao estabelecido na resolução normativa n° 414, de 09 de setembro de 2010, da ANEEL. A instalação é composta de cinco conjuntos motobombas que são acionados de acordo com as sazonalidades do consumo de água tratada no sistema de abastecimento. Na configuração de projeto, dois conjuntos motobombas eram reservas operacionais e, portanto, até três equipamentos eram acionados de maneira paralela. A partir de janeiro de 2016, por uma necessidade operacional de maior vazão disponibilizada ao sistema de abastecimento, um dos equipamentos reservas foi colocado em operação. Com esse aumento do volume captado de água bruta e frente aos valores elevados das faturas de energia elétrica, o presente estudo se concentrou na análise de dados anuais operacionais, propondo, com o uso do software EPANET 2.0, o estabelecimento de possíveis cenários que possam resultar em diminuição dos valores pagos à companhia de energia elétrica. Objetivo esse que pode ser atingido através de duas alternativas: contratação de nova modalidade tarifária e/ou diminuição do número de conjuntos motobombas acionados durante o horário de ponta (com ou sem alterações da demanda contratada). As simulações demonstraram que é viável a diminuição do número de conjuntos motobombas acionados, bem como a diminuição do valor da demanda contratada para o mesmo período. Valores próximos aos 21.136,00 R$ mês-1 ou 253.632,00 R$ ano-1 podem ser alcançados com aplicação de simples medidas operacionais/contratuais.

Operating Reserve Demand Curve, Scarcity Pricing and Intermittent Generation: Lessons from the Texas ERCOT Experience

Resolving the resource adequacy problem has been usually entrusted to the imposition of some kind of long-term capacity requirements or to forward markets. The Operating Reserve Demand Curve (ORDC), which is linked to short-term market conditions and does not require central planning, has been presented as an alternative system with which to ensure resource adequacy. Using hourly data from the Texas ERCOT market, we empirically show that ORDC prices are significantly negatively affected by wind generation. We find that, if wind generation is relatively low, a 1% increase in wind generation decreases the ORDC price by around 0.2-0.1%. Moreover, if wind generation is greater than 8,000-9,000 MW, the ORDC price is expected to be zero. This may preclude investors from obtaining clearly perceivable long-term price signals, such as capacity requirements intent.

About the necessity to organize the undeveloped ground water deposits

The article considers the issue of streamlining of groundwater operational reserves in the State Ba­lance of Minerals of Ukraine, taking into account their development. It was proposed to create within the State balance of mineral deposits of Ukraine a separate reserve of groundwater deposits that had not been developed for 10 years after they were approved. This reserve should also include groundwater reserves, which were tested by decisions of the Scientific and Technical Councils of industrial geological enterprises of the Ministry of Geology of the Ukrainian SSR and its successors, as well as those reserves, the use of which is not planned as a result of revaluations due to a decrease in water users’ needs. 
 The proposed changes in the approaches to the removal from the inventory of groundwater reserves of deposits that have not been commissioned for a long time and their further use is impossible as a result of the construction of buildings jf the territory of deposits, their destruction or pollution of groundwater.

Multi-state operating reserve model of aggregate thermostatically-controlled-loads for power system short-term reliability evaluation

Thermostatically-controlled-loads (TCLs) have been regarded as a good candidate for maintaining the power system reliability by providing operating reserve. The short-term reliability evaluation of power systems, which is essential for power system operators in decision making to secure the system real time balancing, calls for the accurate modelling of operating reserve provided by TCLs. However, the particular characteristics of TCLs make their dynamic response different from the traditional generating units, resulting in difficulties to accurately represent the reliability of operating reserve provided by TCLs with conventional reliability model. This paper proposes a novel multi-state reliability model of operating reserve provided by TCLs considering their dynamic response during the reserve deployment process. An analytical model for characterizing dynamics of operating reserve provided by TCLs is firstly developed based on the migration of TCLs’ room temperature within the temperature hysteresis band. Then, considering the stochastic consumers’ behaviour and ambient temperature, the probability distribution functions of reserve capacity provided by TCLs are obtained by cumulants. On this basis, the states of reserve capacity and the corresponding probabilities at each time instant are obtained for representing the reliability of operating reserve provided by TCLs in the LZ-transform approach. Case studies are conducted to validate the proposed technique.

Социально-педагогические аспекты формирования студенческого потенциала как кадрового резерва

We present the social and pedagogical aspects of the formation of student potential as a personnel reserve. We reveal the functions and applied tasks of the social and pedagogical activity of the formation of student potential as a personnel which includes diagnostic, organizing, educating, developing, correcting, forming, prognostic components. We distinguish several typologies of the personnel reserve according to the type of activity, the speed of replacing posts, and the level of preparedness of a strategic and operational reserve. We study the student potential as a personnel reserve through an analysis of public opinion among full-time students of higher and secondary specialized educational institutions of Moscow and Tambov. The survey involved 220 full-time students. In addition to the survey, students were interviewed by the heads of various structural divisions and firms in order to find out their opinions on student employment and the formation of student potential as a personnel reserve. We indicate that in the process of formation of the personnel reserve a number of interrelated stages are distinguished: social and psychological study, selection of psychodiagnostic methods, psychodiagnostics and social and psychological prognosis.

The Virtual Power Plant – A Review Of Business Models

The aim of the article is to present a critical comparison of different business models of Virtual Power Plant and pointing out both the common and the unique features for each model. Therefore, the American, German, Finnish, Danish and Australian VPP’s business models are described in the article. The VPP is an IT structure which integrates different types of distributed energy sources, flexible consumers and energy storage with each other and with other market segments in real time through a smart grid. The VPP gives positive effects on electricity grid like ensuring energy security, improving grid stability and reliability, optimization of energy resources use, lowering the load - demand response, regulation of frequency, using operational reserves, management of peak demand. The business model is perceived as a method of increasing and exploitation of company’s resources for preparing new products or services for customers in order to obtain added value (expanding the competition advantage or increasing profitability). A potential VPP’s business model in Polish conditions was proposed in case of two different types of customers.

ТРАНСПОРТНО-ГЕОГРАФІЧНЕ ПОЛОЖЕННЯ ЯК ЧИННИК ФОРМУВАННЯ СХІДНОЄВРОПЕЙСЬКОГО ГАЗОВОГО ХАБУ

The Eastern European gas hub is one of the largest energy projects that can liberalize the natural gas market, integrate the Ukrainian gas transportation system into a European gas pipeline system and ensure the profitability of the country’s underground gas storage facilities. The article considers the geographical position as an important factor in the formation of the East European gas hub. There are analysed the basic parameters of functioning of gas storages in the article. There is also considered the European experience of functioning of gas hubs in the paper. The analysis of functioning of gas hubs of Germany and their connection with gas storage of the country is discovered. In the case of Ukraine, the gas storages of the Western region provides extraordinary manoeuvrability of gas flows, optimization of the operating modes of the energy sector, as well as the creation of necessary operational and strategic gas reserves, which is important in the context of market relations. All these preconditions can serve as a powerful base for the creation of a European-style gas hub in Ukraine. The development of the gas sector in Ukraine has a priority in the context of the implementation of Ukraine’s European integration plans in the economic sphere and is determined not only by the geographical location but also by the technological integration of the gas transportation infrastructure in the Middle East European economic area over the past decades. The entry of the Ukrainian natural gas market into the European gas market system will contribute to: enhancement of Ukraine’s energy security; improving the quality and level of relations between Ukraine and the EU countries in cooperation on the gas markets of Central and Eastern Europe; creating a favourable investment climate for the further development of the gas transmission system. Taking into account the European experience, it can be argued that gas storages of Western part of Ukraine, from the transport and logistics point of view, create a powerful base for the formation and further operation of the East European gas hub.

High Efficiency Operational Reserve by SOFC for the Effective Grid Integration of Variable Renewable Energies

For an effective grid integration of a large share of intermittent renewable energy sources such as a photovoltaic and a wind power, the flexible operation of the centralized or decentralized thermal power plants are required as a control reserve of demandsupply balance (frequency control). It is cleared that the Solid Oxide Fuel Cell and Gas Turbine (SOFC/GT) with additional air compressor system offers high efficiency in the wide range load operation. The efficiencyload ratio curve of the Gas Turbine Combined Cycle (GTCC) and SOFC/GT with air compressor system are applied to the secondary control reserve (SCR) operation units, and the daily schedule of power units in the modelled power grid is calculated. Since the efficiency at low load is high in SOFC/GT with air compressor system, the total fuel cost of the modelled power grid diminishes in the case that the SOFC/GT with air compressor system is operated at low load as a load frequency control (LFC) unit for the SCR.

ВЫБОР РЕЗЕРВОВ ГЕНЕРИРУЮЩЕЙ МОЩНОСТИ С УЧЕТОМ СОЛНЕЧНОЙ ЭНЕРГЕТИКИ

The paper considers the impact of electricity on the environment. The method of selection of the operational reserve of generating capacity taking into account solar energy is offered.

Architectural-Typological Innovations as a Key Factor for Sustainable Development of Specially Protected Natural Areas

The issues of improving the architectural solutions of the objects of infrastructure for specially protected natural areas of the Russian Federation considered from the point of view of tourist activity activation. Extensive international experience analyzed. The relationship investigated between the typological diversity of buildings and structures and the categories of territories, which is determined depending on the landscape value and the mode of operation (reserves, national parks, natural parks, nature sanctuary, natural monuments, arboretums and botanical gardens). The conclusions were that the development of scientific research and educational activities in natural areas and settlements with active tourist traffic should be associated with the design and construction of multifunctional buildings, saturation of areas with municipal and engineering facilities contributes for the safety of operation, the use of resource-saving technologies increases the comfort of people’s stay.

Evaluation and Sequential Dispatch of Operating Reserve Provided by Air Conditioners Considering Lead–Lag Rebound Effect

Air conditioners (ACs) are widely considered as good candidates to provide operating reserve. Demand response rebound, i.e., the rebound peak of aggregate power, may exist when ACs are controlled by changing the set point temperature. The rebound peak during the recovery period, named lag rebound, may cause significantly higher demand than that prior to the reserve deployment event. The rebound peak during the reserve deployment period, named lead rebound, is rarely considered in previous researches but will constrain the duration time to a short period (e.g., 10 min), which greatly limits the utilization of ACs. This paper proposes an optimal sequential dispatch strategy of ACs to mitigate the lead–lag rebound, and thus realize flexible control of the duration time from minutes to several hours. To quantify the effects of lead–lag rebound, a capacity-time evaluation framework of the operating reserve is developed. On this basis, ACs are grouped to be dispatched in sequence to mitigate the lead–lag rebound. The co-optimization of sequential dispatch on the capacity dimension and time dimension forms a mixed-integer nonlinear bilevel programming problem, in which the consumers’ thermal comfort is also guaranteed. Case studies are conducted to validate the proposed strategy.

Does The Increase in Wind Generation in ERCOT Justify An Arbitrary Increase to its ORDC LOLP Calculation

A suggestion of multiplying the standard deviation () used in the Electric Reliability Council of Texas’ (ERCOT) Operating Reserve Demand Curve (ORDC) loss of load probability (LOLP) by a factor greater than 1.0 has been posited to solve the “missing money argument.” After the fact justification for this position has been given by the rational assumption that the increase in intermittent generation in ERCOT (mostly wind) has increased the LOLP but has not resulted in a corresponding increase in the standard deviation used in the equation. No supporting data has been provided for this rational hypothesis. This paper provides some supporting data of increased intermittency and provides an analysis (with assumptions) of the data to estimate the factor (calculated to be 1.02 to no more than 1.08) to be applied to the standard deviation to account for the increase in intermittent generation in ERCOT. Other less controversial methods of eliminating this perceived shortcoming of the ERCOT LOLP are also discussed.

Better Forecasting by ERCOT has Reduced the ORDC LOLP Even As Intermittent Generation Capacity has Increased

The suggestion of multiplying the standard deviation () used in the Electric Reliability Council of Texas’ (ERCOT) Operating Reserve Demand Curve (ORDC) loss of load probability (LOLP) by a factor greater than 1.0 has been posited to solve the “missing money argument.” Historical data from 2015 through 2017 supports this theory, although the calculated factor is only 1.02. This working paper compares the ERCOT 2015 LOLP distributions with the 2018 distributions. 21 of 24 distributions have seen their standard deviation decrease, despite the historical data that shows that the standard deviation of distribution of one hour change in wind generation has increased. Additionally, the change in the mean of the summer time distributions result in a shifting away from the minimum contingency level. These two outcomes both produce a lower LOLP for a given reserve level in 2018 compared to 2015. This is caused by more accurate forecasting by ERCOT. The greater forecasting accuracy overcomes the increase in change of wind generation over an hour resulting in a reduced LOLP. Further evidence suggests that in the windy, low load months, when wind generation makes up a larger percentage of total energy produced, the change in the mean of the distributions does reflect the increase in LOLP caused by intermittent generation. An analysis of the proposal to “shift the mean error by one standard deviation” is performed showing that is identical to increasing MCL by one standard deviation. Variations on this proposal are analyzed. ERCOT 2015 data (linked in references and recorded with Mendeley) is evaluated with the proposal to shift the mean error of the distribution by a standard deviation and the variations, and the increase electricity cost from the proposals ranges from $2.4 billion to $5.75 billion per year. Finally, the foundational problem of using a forecasted error distribution to model a scarcity pricing mechanism instead of a market driven change in price model is briefly discussed.

Dynamic dimensioning approach for operating reserves: Proof of concept in Belgium

This article discusses a new method for the sizing of operating reserves by electric power system operators. Operating reserves are used by system operators to deal with unexpected variations of demand and generation, and maintain a secure operation of the system. This becomes increasingly challenging due to the increasing share of renewable generation based on variable resources. This paper revisits the current sizing method applied in Belgium, which is based on a static approach that determines the required capacity once a year. The presented dynamic sizing method determines the required capacity on a daily basis, using the estimated probability of facing a system imbalance during the next day. This risk is estimated based on historical observations of system conditions by means of machine learning algorithms. A proof of concept is presented for the Belgian system, and demonstrates that the proposed methodology improves reliability management while decreasing the average capacity to be contracted. The method is compliant with European market design, and the corresponding regulatory framework, and is of particular interest for systems with a high share of renewable generation. For these reasons a gradual implementation in Belgium towards 2020 has been decided based on the results of this study.

Impact Evaluation of Wind Power Geographic Dispersion on Future Operating Reserve Needs

This paper evaluates the potential of diverse wind power patterns to balance the global power output of wind farms using the concept of operating reserve assessment. To achieve this, operating reserve assessment models are utilized to evaluate bulk generation systems under several conditions of wind power geographic distribution. Different wind behavior patterns and wind power penetration levels are tested using a modified configuration of the Institute of Electrical and Electronics Engineers Reliability Test System 96 (IEEE RTS-96). The results highlight that on a large country scale system with different wind characteristics, the diversification of wind behavior might be conducive to a compensation of wind power fluctuations, which may significantly decrease the need for system operating reserves. This effect is verified using probability distribution functions of reserve needs estimated by sequential Monte Carlo simulations (SMCS), such that useful information regarding generation capacity flexibility is drawn from the evaluations.

Techno-economic analysis and size optimization of an off-grid hybrid photovoltaic, fuel cell and diesel generator system

This paper presents multi-objective design of a hybrid system composed of photovoltaic (PV), fuel cell (FC) and diesel generator (DG) to supply electric power of an off-grid community in Kerman, south of Iran in the presence of operating reserve (OR) and uncertainties of load and solar power. Total net present cost (TNPC) and loss of power supply probability (LPSP) are considered as the objectives and the decision variables are the number of PV panels, DGs, FCs, electrolysers and hydrogen tanks. A recently developed meta-heuristic optimizer, multi-objective crow search algorithm (MOCSA), has been utilized to find Pareto front. The impact of different parameters (fuel price, FC system equipments cost, emission cost, etc) has been investigated on the sizing problem. Based on the simulation results, it is observed that integration of hydrogen energy technology will reduce the total cost of the hybrid energy systems. Moreover, the impact of OR on the Pareto front is more than that of load and solar power uncertainties.

Influences and uncertainty of battery-swapping electric scooters on energy system in Taiwan

This paper proposes a new formula to estimate the electricity demand from battery-swapping stations (BSSs) at peak hours, combining parameters of the number of battery-swapping electric scooters (NBSES) and the number of scooters served per BSS. It also presents a novel decision-support analysis for assessing future impact on energy system with an increasing NBSES in Taiwan. The VaR (Value at Risk) values and Monte Carlo method are combined to assess key variables of NBSES and potential benefits. This study finds that the probability for the percentage of operating reserve (OR), R, beyond 6.0 percent is only 86.3% in the past four years. When NBSES reaches 1.28 million, the probability for R beyond 6.0 percent is down to 69.0% and R is 2.9% (95%CI) without considering the storage ability of BSSs. However, R could be higher than 6.0% (95%CI) if considering the storage ability of BSSs.

Development of a tool for urban microgrid optimal energy planning and management

Small-sized variable renewable energy sources (RES) live a large-scale development in urban electrical systems. They increase local high dynamic unbalancing and then can create instabilities on the inertia response. Thus, setting an adequate operating reserve (OR) power to compensate the unpredicted imbalance between RES generation and consumption is essential for power system security. Indeed, effective calculation and dispatching of OR considering inaccurate forecast of both RES and load demand can provide substantial cost reductions. Thus, to facilitate the energy management and system optimization in an urban microgrid (MG), a user-friendly tool for Energy Management System and Operational Planning has been developed. The tool provides a complete set of user-friendly graphical interfaces to study the details of photovoltaic (PV) and batteries, load demand, as well as micro gas turbines (MGTs). Furthermore, this energy management system allows system operators to properly model RES uncertainty. In addition, it could assist operators for the day-ahead energy management with an efficient information system and an intelligent management.

Economic Analysis of Operating Reserve Using Forecasted Variable Renewable Generation

Economic Analysis of Operating Reserve Using Forecasted Variable Renewable Generation

Modeling of Operating Reserve Demand Curves and System-Level Price Adders in Real-Time Energy-Only Market

In order to support an appropriate level of resource adequacy in the long term and also to achieve a reliable operation in the short term, a new pricing design and mechanism is needed as a key success factor of real-time energy-only market. This paper proposes optimization-based mathematical models to explore operating reserve demand curves (ORDCs) and two price adders in real-time energy-only market, including dispatch correction and extended security-constrained economic dispatch. The Lagrangian multipliers of the dispatch correction problem are used to construct the ORDCs. Then, the derivative of the ORDCs’ social welfare is formulated as real-time online reserve price adders such as the scarcity adder and the price-lift adder. In case studies, we justify the effectiveness of the proposed ORDCs and two price adders by a simple example with two aggregated units and the Electric Reliability Council of Texas data.