Times Of Low Demand Research Articles

Enhancing Distribution Grid Efficiency and Congestion Management through Optimal Battery Storage and Power Flow Modeling

The significant growth in demand for electricity has led to increasing congestion on distribution networks. The challenge is twofold: it is needed to expand and modernize our grid to meet this increased demand but also to implement smart grid technologies to improve the efficiency and reliability of electricity distribution. In order to mitigate these congestions, novel approaches by using flexibility sources such as battery energy storage can be used. This involves the use of battery storage systems to absorb excess energy at times of low demand and release it at peak times, effectively balancing the load and reducing the stress on the grid. In this paper, two optimal power flow formulations are discussed: the branch flow model (non-convex) and the relaxed bus injection model (convex). These formulations determine the optimal operation of the flexibility sources, i.e., battery energy storage, with the objective of minimizing power losses while avoiding congestions. Furthermore, a comparison of the performance of these two formulations is performed, analyzing the objective function results and the flexibility operation. For this purpose, a real Spanish distribution network with its corresponding load data for seven days has been used.

Model predictive control of a Lab-Scale thermal energy storage system in RELAP5-3D

Increased renewable energy penetration of an electrical grid generally creates more supply fluctuations. Traditional base-load systems, such as nuclear power, can be retrofitted with thermal energy storage (TES) systems to meet supply demand fluctuations. These systems can store energy during low electricity demand times to allow the reactor to operate at constant power while simultaneously fluctuating electricity output. The control of these systems is of vital importance and Model Predictive Control (MPC) is a leading control mechanism for optimized production plans with forecast information. This study combines high fidelity RELAP5-3D models with MPC to control an experimental benchtop system that approximates expected nuclear power thermal-hydraulics. RELAP5-3D is a high-fidelity code utilized for thermal–hydraulic phenomenon simulations for nuclear applications. The United States Nuclear Regulatory Commission (NRC) has supported the use of this code for licensing purposes. The NRC requires in depth testing before nuclear plants can be built or changed. The use of MPC with RELAP5-3D is used here to demonstrate the potential of a lab-scale TES coupled with a high-fidelity thermal–hydraulic model for use in the NRC licensing process.

Influences on hydrogen production at a wind farm

If an affordable infrastructure for low-carbon-intensity hydrogen can be developed, then hydrogen is expected to become a key factor in decarbonizing the atmosphere. This research focuses on factors an existing wind farm operator would consider when weighing participating in the electricity market, the hydrogen market, or both.The solutions depend on the state of technology, which is changing rapidly, the local market structures, the local natural resources, and the local pre-existing infrastructure. Consequently, this investigation used an assessment approach that examined the variation of net present value. The investigation identified profitability conditions under three different scenarios: 1) Make and sell what makes economic sense at the time of production, 2) Use electrolyzer and fuel cell to consume power from the grid at times of low net demand and to produce electricity at times of high net demand, 3) Same as #2 but also market hydrogen directly when profitable.

Optimal Schedule the Operation Policy of a Pumped Energy Storage Plant Case Study Zimapán, México

Pumped-storage hydroelectric plants are an alternative to adapting the energy generation regimen to that of the demand, especially considering that the generation of intermittent clean energy provided by solar and wind power will cause greater differences between these two regimes. In this research, an optimal operation policy is determined through a simulation tool that allows the annual benefits under the energy arbitration service (purchase–sale) to be estimated, considering the variations of the energy price in Mexico. A case study is proposed in the Zimapán hydroelectric facility, where reservoir operation at the hourly level is simulated with records for a period of 3 years, considering historical values. The results establish that this type of pumped storage power plant obtains greater benefits by generating electrical energy during 8 h of high demand and pumping for more than 11 continuous hours in times of low demand. With this configuration, the PHES consumes 82.33 GWh/year more energy than it produces, and the energy generated is 210.83 GWh/year; however, when considering the energy arbitration service, a net income of more than USD 3.25 million per year is identified, which represents a 123.52% increase for the annual energy purchase.

Review of Hydrogen Production Techniques from Water Using Renewable Energy Sources and Its Storage in Salt Caverns

Hydrogen is becoming an increasingly important energy carrier in sector integration for fuel cell transportation, heat and electricity. Underground salt caverns are one of the most promising ways to store the hydrogen obtained from water electrolysis using power generation from renewable energy sources (RES). At the same time, the production of hydrogen can be used to avoid energy curtailments during times of low electricity demand or low prices. The stored hydrogen can also be used during times of high energy demand for power generation, e.g., with fuel cells, to cover the fluctuations and shortages caused by low RES generation. This article presents an overview of the techniques that were used and proposed for using excess energy from RES for hydrogen production from water and its storage techniques, especially in underground salt caverns, for the aforementioned purpose, and its feasibility. This paper compares and summarizes the competing technologies based on the current state-of-the-art, identifies some of the difficulties in hydrogen production and storage, and discusses which technology is the most promising. The related analysis compares cost and techno-economic feasibility with regard to hydrogen production and storage systems. The paper also identifies the potential, technical challenges and the limitations associated with hydrogen integration into the power grid.

Turn-Down Capability of Ansaldo Energia's GT26

Abstract The operational flexibility of heavy-duty gas turbines is of increasing importance in today's power generation market. Fast startup, fast loading, grid frequency support, fuel flexibility, and turn-down capability are only some of the keywords that describe the challenges for GT manufacturers. This paper reports Ansaldo Energia's activities to further reduce the minimum environmental load of the GT26. The difficulties related to operation at very low loads and the solutions that were developed are explained. Furthermore, the results of engine validation tests of the new extended low load operation and extended low part load operation concepts are presented. The enhancement of the operational flexibility of the GT26 is in the focus of Ansaldo's development activities since many years. Its sequential combustion system is a very good basis for flexible and emission compliant operation down to very low loads. Ansaldo Energia's low part load (LPL) and low load operation (LLO) concepts are standard products in the GT26 flexibility portfolio and established in the market for many years. LPL operation extends the standard operating range down to low loads by switching off individual burners in the second combustor (sequential environmental (burner) (SEV) combustor). The compressor mass flow can be varied between idle and base load levels. Low load operation is characterized by a combination of idle compressor mass flow and base load temperatures in the first combustor (environmental (burner) combustor). The SEV combustor is switched off. LLO is intended to be a “parking point,” where the plant can operate in combined cycle mode during times of low electricity demand. Ansaldo Energia has conducted a development project in the past two years to further reduce the minimum simple cycle and combined cycle loads. The extension of the LLO and LPL operating ranges and their combination into one single feature are the main targets of the project.

Facilitating higher photovoltaic penetration in residential distribution networks using demand side management and active voltage control

AbstractFuture power networks are certain to have high penetrations of renewable distributed generation such as photovoltaics (PV). At times of high PV generation and low customer demand (e.g., summer), network voltage is likely to rise beyond limits mandated by grid codes resulting in a curtailment of PV generation, unless appropriate control means are used. This leads to a reduction in energy yield and consequently reduces the economic viability of PV systems. This work focuses on scenario‐based impact assessments underpinned by a net prosumer load forecasting framework as part of power system planning to aid sustainable energy policymaking. Based on use‐case scenarios, the efficacy of smart grid solutions demand side management (DSM) and Active Voltage Control in maximizing PV energy yield and therefore revenue returns for prosumers and avoided costs for distribution networks between a developed country (the UK) and developing country (India) is analyzed. The results showed that while DSM could be a preferred means because of its potential for deployment via holistic demand response schemes for India and similar developing nations, technically the combination of the weaker low voltage network with significantly higher solar resource meant that it is not effective in preventing PV energy curtailment.

WITHDRAWN: Dynamic power load distribution using simulated annealing

Load balance, load matching, or frequent demand reserve apply to the usage, during low-demand times of different technology by Power plants to store excess Power. It strives to provide a load factor of 1 in the Power supply device. Network energy storage holds Power beyond the customer's transmission system. Alternatively, the energy may often be dispersed and consumer active, For example, in the case of demand-response storage heaters, such as the UK's economy, or car-to-grid storage networks, which can use electric car storage in high hours, and then reload in off-peak times. These require customer benefits to join, typically by higher off-peak energy prices. Telephone exchanges also have a variety of batteries in their Power plants, which in former Underground networks like the London Underground do not only have their own strength plants, but also the grid to balance loads. Now these supplies are mostly supplemented by a direct grid supply and so for the purposes of load balancing they are no longer usable. Load balancing technologies rely on “smart grid” infrastructure, where many customer and enterprise equipment connect with the utilities through automated means and the utilities can be enabled and turned on to work off-peak hours. The power utilities send a signal down the line and to transform a special circuit through a certain telecoms chip with a basic demand balancing system at home. This circuit is usually connected to a room or a water heater storage unit. This manuscript presents the usage patterns of metaheuristics of simulated annealing for the usage patterns in the load balancing of Power systems with huge elevation in the performance.

The Acid-Base Flow Battery: Sustainable Energy Storage via Reversible Water Dissociation with Bipolar Membranes.

The increasing share of renewables in electric grids nowadays causes a growing daily and seasonal mismatch between electricity generation and demand. In this regard, novel energy storage systems need to be developed, to allow large-scale storage of the excess electricity during low-demand time, and its distribution during peak demand time. Acid–base flow battery (ABFB) is a novel and environmentally friendly technology based on the reversible water dissociation by bipolar membranes, and it stores electricity in the form of chemical energy in acid and base solutions. The technology has already been demonstrated at the laboratory scale, and the experimental testing of the first 1 kW pilot plant is currently ongoing. This work aims to describe the current development and the perspectives of the ABFB technology. In particular, we discuss the main technical challenges related to the development of battery components (membranes, electrolyte solutions, and stack design), as well as simulated scenarios, to demonstrate the technology at the kW–MW scale. Finally, we present an economic analysis for a first 100 kW commercial unit and suggest future directions for further technology scale-up and commercial deployment.

An Optimization Model for Operational Planning and Turnaround Maintenance Scheduling of Oil and Gas Supply Chain

Hydrocarbon supply chain (HCSC) is a complex network that extends from oil and gas fields to demand nodes. Integrating operation and maintenance activities along this complex network is crucial since the hydrocarbon industry is the most influential sector in the world economy, and any disruptions or variations in hydrocarbon product supply will affect the whole world economy. Therefore, effective and thoughtful maintenance extends the life of an asset and enhances its reliability. To prevent huge losses in production and ultimately satisfy customer needs, the maintenance jobs are preferred to be performed during times of low demand. Thus, operation planning and maintenance scheduling decisions are dependent and should be optimized simultaneously. Therefore, the aim of this study is to develop an integrated mathematical model for the operation and maintenance planning of the oil and gas supply chain. The utility of the proposed model has been demonstrated using the Saudi Arabian HCSC. The proposed model effectively produces optimal operation and maintenance schedule decisions. A sensitivity analysis was conducted to study the effect of critical parameters on the obtained results.

Reducing Emissions and Costs with Vehicle-to-Grid

Determining when and how to charge electric vehicles to minimize costs and potential greenhouse gas emissions is a complex optimization problem. Recently in Applied Energy, Brinkel et. al. developed a multi-objective smart charging method that can reduce costs and cut carbon emissions without upgrading existing grid infrastructure in model case scenarios.

Examining the relationships between innovation, quality, productivity, and customer satisfaction in pure service companies

PurposeThis study investigates the relationships between innovation, quality, productivity and customer satisfaction in pure service companies. Previous studies have shown a negative relationship between quality and productivity in services. However, we argue the two can be positively related when innovation is present.Design/methodology/approachThis paper develops and tests hypotheses using secondary data from COMPUSTAT, KLD STAT and the American Customer Satisfaction Index (ACSI). We test these hypotheses using ordinary least squares regression and conduct additional testing using path analysis.FindingsThe findings show that quality and productivity are positively related when innovation is present in pure service companies. The findings also reveal find that innovation is antecedent to both service quality and productivity which in turn positively affect customer satisfaction.Practical implicationsBoth companies and customers can increase their outcomes including higher levels of service quality, productivity and customer satisfaction. Managers should therefore design innovative systems that enable customers to participate in service production. Other innovative systems may help to increase capacity utilization by smoothing high and low demand times, thus increasing both service quality and productivity.Originality/valueThis study contributes to service research by identifying innovation as the key to simultaneously increasing service quality and productivity. The authors find empirical support for a model in which service quality and productivity have a complementary relationship leading to customer satisfaction with innovation as an antecedent, and we do so using a sample of pure service firms.

Mothballing in a Duopoly: Evidence from a (Shale) Oil Market

The mothballing option has been studied in the literature, but mainly in decision theoretic frameworks. This paper looks at it from a strategic point of view and applies it to an incumbent-entrant framework. In particular, based on the recent strategic interactions between OPEC and the shale oil industry, we conduct a case study where the incumbent OPEC is a exible producer that competes with a representative shale oil firm. Upon entry, the latter produces a fixed amount but it can apply the mothballing option in times of low demand. Our main results are threefold. First, we find that under low demand uncertainty, the mothballing option has a negative effect on the value of the entrant. Second, a large market share of the entrant will stimulate mothballing, caused by a so-called squeeze strategy of the incumbent. Third, our empirical analysis of the (shale) oil market learns that a higher demand elasticity induces mothballing.

Power System Stability Enhancement Using FACTS Devices

To utilize maximum cross section of installed power system conductors, the diversion of imaginary power should be must .With this; we can achieve maximum utilization of real power generated at the station. Generally preset passive inductive VAR generators may share conductor portion when low demand times. Active VAR generators are preferred to overcome this issue .Further control systems helps to determine the required VAR and type of VAR such that conduction period of switch varies according to the requirement of load which is very advantageous nature of active VAR generators. The simulink models of STATCOM and SVC are present in this paper. The results are analyzed accordingly in this paper.

P6V2G: a privacy-preserving V2G scheme for two-way payments and reputation

The number of electric vehicles (EVs) is steadily growing. This provides a promising opportunity for balancing the smart grid of the future, because vehicle-to-grid (V2G) systems can utilize the batteries of plugged-in EVs as much needed distributed energy storage: In times of high production and low demand the excess energy in the grid is stored in the EVs’ batteries, while peaks in demand are mitigated by EVs feeding electricity back to the grid. But the data needed for managing individual V2G charging sessions as well as for billing and rewards is of a highly personal and therefore sensitive nature. This causes V2G systems to pose a significant threat to the privacy of their users. Existing cryptographic protocols for this scenario either do not offer adequate privacy protection or fail to provide key features necessary to obtain a practical system.Based on the recent cryptographic toll collection framework P4TC, this work introduces a privacy-preserving but efficient V2G payment and reward system called P6V2G. Our system facilitates two-way transactions in a semi online and post-payment setting. It provides double-spending detection, an integrated reputation system, contingency traceability and blacklisting features, and is portable between EVs. The aforementioned properties are holistically captured within an established cryptographic security framework. In contrast to existing protocols, this formal model of a V2G payment and reward system allows us to assert all properties through a comprehensive formal proof.

Techno-economic assessment of polygeneration based on fluidized bed gasification

The electric power sector contributes to about a quarter of the total CO2 emissions worldwide. Therefore, in most mitigation scenarios for the climate change the share of low-carbon electricity supply increases from the current share of approximately 30% to more than 80% by 2050. A promising approach is the polygeneration concept for electrical power and chemicals based on integrated gasification combined cycle. It offers the possibility to capture CO2 in a very efficient pre-combustion process and is able to accommodate the intermittent renewable power generation from wind and solar while operating the gasification island at full load by producing synthetic chemical products during times of low power demand. In this work, a process model of a polygeneration plant including a 350 MWel combined cycle power plant with a fluidized bed dryer, a fluidized bed gasifier, a gas purification unit, a CO-Shift unit, a Rectisol acid gas removal, and a synthesis reactor array is developed. The model is used to investigate the specific CO2 emissions and the process efficiency for different operation modes for power and methanol production. The model offers two options to introduce excess electricity from renewable sources into the process: via hydrogen from electrolysis or via additional drying and heating of the feedstock. The influence on the process efficiency and the economics are assessed.

Technology Focus: Natural Gas Processing and Handling (April 2019)

Technology Focus To cater to the seasonal highs and lows in demand throughout a year, natural gas is stored in underground storage facilities. The need for such facilities arose because increasing (or decreasing) gas production to mirror changes in demand is neither practical nor economical. Therefore, gas is produced and stored during low-demand times and retrieved to meet the highs during winters. This cyclic trend can be observed also in gas-storage inventories [as reported by the Energy Information Administration (EIA)]. The northeast US has the highest concentration of such storage facilities, close to the biggest market. Most of the underground gas-storage facilities are depleted reservoirs, but aquifers and leached salt caverns are also used. The US and Canada were the pioneers in realizing the potential of depleted reservoirs for gas storage and, hence, have several well-developed facilities. What makes depleted reservoirs attractive is the presence of existing wells used to produce the reservoir, plus the geologic and engineering knowledge acquired during the development of the field. All that information is leveraged when repurposing the field for gas storage. Depleted reservoirs also contain some amount of gas already in the reservoir, which decreases the requirement to inject gas as cushion gas. (Cushion gas is immobile gas that remains in the reservoir and allows the reservoir to be used for storage.) Depleted reservoirs are also the most abundant. I would be remiss not to touch upon the Aliso Canyon incident of 2015. Aliso Canyon was the second-largest storage facility in the US at the time. The industry learned a harsh lesson about the repercussions when containment is lost for such facilities. The loss of containment was because of the casing failure of one of the wells (along with having subsurface safety valves removed in the past). This led to 109,000 tonnes of methane emissions by some estimates. One measure that was proposed to reduce such risks is to use offshore reservoirs nearing abandonment for gas storage (instead of onshore ones that are close to populated urban areas). At the time of this writing, the week-to-week change in the natural gas storage inventory was –237 Bcf, and levels remained lower than the 5-year historical average, according to the EIA. This withdrawal from the inventory was less than most forecasts based on the extreme cold temperatures faced by the US. The Henry Hub natural gas prices reached highs of more than $4.5/million Btu in 2018 because of record gas demand. The price has since dipped to $2.57/million Btu because of abatement in the extreme weather leading to lower demand for heating. To learn more, visit the SPE Annual Technical Conference and Exhibition in Calgary, 30 September–2 October, and the Gastech Exhibition and Conference in Houston, 17–19 September. Recommended additional reading at OnePetro: www.onepetro.org. SPE 190838 Comprehensive Evaluation of the Dynamic Sealing Capacity of Clayey Caprocks in a Large Underground Gas Storage by Junchang Sun, PetroChina, et al. SPE 192961 Maintaining Flare-Tip Health by Venugopal Bakthavachsalam, ADNOC, et al. SPE 192783 Cutting-Edge Solutions for Sour-Gas Treatment: A Retrospective Study by Kuwait Oil Company by Fahad Al-Ghanem, Kuwait Oil Company, et al.

Investigation of viability of seasonal waste heat storage in rock piles for remote communities in cold climates

Communities situated in distant areas are deemed as 'remote' and have either very limited or no access to power grid lines. Therefore, most of these communities greatly depend on diesel-burning for power and heat provision at all times. Nonetheless, nearly 30% of the energy associated with the diesel burning and power generation process is dissipated as heat through the exhaust streams of diesel generators. The waste heat in the exhaust stream is usually recovered during the winter season and directly used as a heat source when the communal heat demand is peaked. However, recovery of this energy potential is usually discarded during the summer period due to the low demand. Seasonal thermal storage on rock piles is a developing concept that can be a low-cost solution to resolve this issue. This paper proposes utilization of the heat wasted through the exhaust stream of diesel generators on rock piles as temporary storage during low demand times. In this sense, a remote cold climate community, such as those of Canada and Norway, is selected and potentiality of the seasonal rock pile thermal storage is investigated and presented.

Investigation of Energy Storage Batteries in Stability Enforcement of Low Inertia Active Distribution Network

The inherent intermittency of renewable power generation poses one of the great challenges to the future smart grid. With incentives and subsidies, the penetration level of small-scale renewable energy into power grids is sharply increasing worldwide. Battery energy storage systems (BESS) are used to curtail the extra power during low demand times. These energy storage systems are capable of absorbing and delivering real power to the grid. The increased penetration level of inverter-based distributed generation (DG) reduces the inertia of the grid and thus affects the transient stability of the network. This paper discusses and investigates the impact of BESS on distribution networks’ stability with high penetration levels of inverter based DG. The obtained results show that proper charging and discharging schemes of the BESS can enhance the transient stability of the network. Fast switching between charging and discharging mode would be helpful during transient fault disturbance to keep the system in a balanced condition.

Inaccurate consumer perceptions of monetary savings in a demand-side response programme predict programme acceptance

Demand-side response (DSR) measures are critical to integrating variable renewable generation into electric grids. Time-of-use rates (TOU) are a common DSR mechanism that seeks to shift electricity use to low-demand times using financial instruments. However, consumers generally have a poor understanding of their electricity use and bills, raising questions about the extent to which TOU participation is driven by perceptions of savings versus actual savings. We find that among 8,702 residents who opted into a pilot TOU programme, the TOU treatment decreases on-peak use compared to a control group, but this effect is small. Perceived savings is the strongest predictor of intent to remain on TOU, over and above actual savings, even though it is only weakly related to actual changes in bills and usage. Residents may thus join DSR programmes based on perceived savings without achieving actual monetary or energy use savings, which may undermine the goals of these programmes. Time-of-use tariffs aim to shift energy use to better match available supply. This study shows that perception of savings, more so than actual savings, predicts intent to remain enrolled in time-of-use programmes, which may undermine benefits for household finances and energy-reduction goals.