Increase Power Production Research Articles

State-of-the-Art Review on Shipboard Microgrids: Architecture, Control, Management, Protection, and Future Perspectives

Shipboard microgrids (SBMGs) are becoming increasingly popular in the power industry due to their potential for reducing fossil-fuel usage and increasing power production. However, operating SBMGs poses significant challenges due to operational and environmental constraints. To address these challenges, intelligent control, management, and protection strategies are necessary to ensure safe operation under complex and uncertain conditions. This paper provides a comprehensive review of SBMGs, including their classifications, control, management, and protection, as well as the most recent research statistics in these areas. The state-of-the-art SBMG types, propulsion systems, and power system architectures are discussed, along with a comparison of recent research contributions and issues related to control, uncertainties, management, and protection in SBMGs. In addition, a bibliometric analysis is performed to examine recent trends in SBMG research. This paper concludes with a discussion of research gaps and recommendations for further investigation in the field of SBMGs, highlighting the need for more research on the optimization of SBMGs in terms of efficiency, reliability, and cost-effectiveness, as well as the development of advanced control and protection strategies to ensure safe and stable operation.

Exergy analysis of a negative CO[formula omitted] emission gas power plant based on water oxy-combustion of syngas from sewage sludge gasification and CCS

A power cycle with water-injected oxy-combustion (water cycle) is investigated by exergy analysis. It is fueled with syngas (aka. producer gas) from gasification of sewage sludge. The cycle is equipped with a spray-ejector condenser (SEC). CO2 is separated and compressed for transportation and storage. The net delivered electric power is 31% of the fuel exergy. The task efficiency is 39% when the flue gas bleed to gasification and O2 penalty are subtracted from fuel, and CO2 capture is included in the useful product. The large part of exergy destruction, 80%, pertains to the combustor. Increasing the temperature or the pressure of the combustor outlet (turbine inlet) lead, as expected, to reduced exergy destruction and more power delivery. Reducing pressure of the gas turbine outlet (SEC inlet) also increases power production. Varying pressure and temperature of the SEC outlet affects the distribution of exergy destruction among units of the condenser, however scarcely the overall efficiency. Reducing the ambient temperature, including cooling water temperature, reduces the efficiency of the plant, contrary to the effect of conventional plants. The reason is that the low pressure of SEC relies on the pressure and mass flow of injected water, rather than the temperature.

CFD Investigation of a Hybrid Wells Turbine with Passive Flow Control

In the past decade, there has been renewed interest in wave energy harvesting utilizing oscillating water columns (OWC), one of the most well-studied wave energy harnessing technologies. In the OWC, pneumatic power from ocean waves is converted to mechanical energy by Wells turbines. It should be noted, however, that such turbines tend to perform poorly, have a limited operating range, and have low efficiency. In the present study, we incorporate a rectangular Gurney flap (GF) at the trailing edge (TE) of a Wells turbine consisting of hybrid airfoil (NACA 0015 and NACA 0025) blades with variable chord distribution along the span. This passive flow control mechanism was adopted to achieve increased power production by the Wells turbine. This study aimed to determine the aerodynamic performance of the variable chord turbine with GF compared to a turbine with a constant chord. By using ANSYS™ CFX, the three-dimensional, steady-state, incompressible Reynolds averaged Navier–Stokes (RANS) equations coupled with the k-ω SST turbulence model are solved. The performance was evaluated through the use of non-dimensional coefficients of torque, pressure drop, and efficiency. In addition, the numerical accuracy was achieved through a grid independence study. There was a good agreement between the computed results and the available experimental and numerical data. The GF increased the torque coefficient by 18.6% and 47.3% but with the expense of peak efficiency of 8.5% and 7.4% for the baseline and the hybrid turbine, respectively. Additionally, the hybrid turbine with GF delayed the onset of the stall by ~3° angle of attack (AOA).

Hydrodynamic design of a horizontal axis current turbine with passive flow control using vortex generator and inserted tube

ABSTRACT Energy from river currents is one of the available renewable energy sources to produce electricity. An improvement in the efficiency of the horizontal axis current turbine is required for the successful utilization of this energy. This paper compares the power production of a horizontal axis current turbine and a turbine with two passive flow control attachments, the vortex generator, and the inserted tube. Firstly, the NACA S1210 hydrofoil shape has been selected. Then the variation of chord length and twist angle along the blade span has been determined. Finally, a 5-meter-diameter, three-bladed, horizontal-axis current turbine has been designed using the blade element momentum theory.The rotor has a maximum power coefficient and a maximum power of 0.47 and 42.71 kW, respectively, at the current speed of 2.1 m/s and a tip speed ratio of 6 when the hydrofoil with tubes has been chosen to design the horizontal axis current turbine. It has been proven that including vortex generators and tubes on the turbine can help increase power production by 9.8% and 14.7%, respectively.

Re-designing district heating networks through innovative CO2 solutions

One of the main problems of current district heating networks is the significant heat losses that occur due to the high temperature of the heat distribution fluid (usually, water in the Italian climate conditions). Moreover, in ORC- or steam-turbine-based cogeneration power plants, the heat distribution fluid is heated directly by the condenser of the ORC cycle resulting in low efficiency of the power production section of the system. Considerable power is also employed for pumping the district heating flow rate through a long distribution ring. In this work, the effect of replacing water with low-temperature CO2 as a working fluid in a district heating network is analyzed. Specifically, a real district heating installation (the Biogenera-Calenzano network) providing at design conditions 850 kW of electricity and 1.7 MW (average) of heat is assessed using an experimental data set, simulating the equivalent working conditions with CO2 distributed through the network.The proposed innovative solution continues to receive the heat from the condenser of an ORC cycle, but the temperature of the working fluid is significantly lower providing a relevant increase in the power production because of the reduction of the condenser temperature (determining an increase of the expansion ratio of the turbine). The increased power production of the turbine exceeds the power needed by local heat pumps which should be installed near the utilities of the district heating network to provide flexible heat on demand.

FarmConners wind farm flow control benchmark – Part 1: Blind test results

Abstract. Wind farm flow control (WFFC) is a topic of interest at several research institutes and industry and certification agencies worldwide. For reliable performance assessment of the technology, the efficiency and the capability of the models applied to WFFC should be carefully evaluated. To address that, the FarmConners consortium has launched a common benchmark for code comparison under controlled operation to demonstrate its potential benefits, such as increased power production. The benchmark builds on available data sets from previous field campaigns, wind tunnel experiments, and high-fidelity simulations. Within that database, four blind tests are defined and 13 participants in total have submitted results for the analysis of single and multiple wakes under WFFC. Here, we present Part I of the FarmConners benchmark results, focusing on the blind tests with large-scale rotors. The observations and/or the model outcomes are evaluated via direct power comparisons at the upstream and downstream turbine(s), as well as the power gain at the wind farm level under wake steering control strategy. Additionally, wake loss reduction is also analysed to support the power performance comparison, where relevant. The majority of the participating models show good agreement with the observations or the reference high-fidelity simulations, especially for lower degrees of upstream misalignment and narrow wake sector. However, the benchmark clearly highlights the importance of the calibration procedure for control-oriented models. The potential effects of limited controlled operation data in calibration are particularly visible via frequent model mismatch for highly deflected wakes, as well as the power loss at the controlled turbine(s). In addition to the flow modelling, the sensitivity of the predicted WFFC benefits to the turbine representation and the implementation of the controller is also underlined. The FarmConners benchmark is the first of its kind to bring a wide variety of data sets, control settings, and model complexities for the (initial) assessment of farm flow control benefits. It forms an important basis for more detailed benchmarks in the future with extended control objectives to assess the true value of WFFC.

Gait-related Factors That Explain Power Production In Patients Before And After Total Ankle Arthroplasty

Total ankle arthroplasty (TAA) reduces pain and improves joint function, including power production at the ankle. Patients can ambulate at higher velocities and generate greater joint power after TAA. To date, little is known about which factors – angular velocity (AV), ground reaction force (GRF), or range of motion (ROM) – most influence power production before and after TAA. Identifying the factors that affect power production and their relative contribution can provide rehabilitation targets. PURPOSE: To examine the role of ankle kinematics and kinetics in generating power in the last third of the stance phase and to evaluate which factors play the most important role in generating increased power after surgery. It is hypothesized that reduction in pain will primarily increase GRF and AV to a greater degree than ankle ROM. METHODS: Two hundred and eighteen patients (101 male and 117 female; age = 63.1 + 9.4) with requiring TAA were studied using a motion analysis system and force plates before and after TAA. Peak ankle power and associated vertical GRF (vGRF), center of pressure (COP) position, ankle angle, moment and AV were compared before and after surgery using Wilcoxon signed rank tests. Predictive models for pre and post surgical power generation were created using AIC multiple stepwise regression. RESULTS: Following TAA, ankle plantarflexion power increased on both the surgical and nonsurgical limbs (0.83 to 1.1, p < 0.001; 0.97 to 1.4, p < 0.001 respectively). To increase power, patients increased surgical and non-surgical side vGRF (0.51 to 0.58, p < 0.001; 0.51 to 0.57, p = 0.002 respectively) and AR (1.1 to 1.7, p < 0.001; 1.1 to 1.8, p < 0.001 respectively). Ankle ROM did not change significantly on either limb following surgery. Ankle AV and vGRF are the best predictors of peak plantar flexion power across all models, with AV being the strongest single predictor. CONCLUSIONS: TAA improves power production at the ankle by allowing patients to generate a greater force at a higher rate. Increased power production relates to faster and more efficient gait, relieving other joints of the need to generate compensatory power. Pre and post-TAA treatment strategies should focus on helping patients increase vGRF and plantarflexion angular velocity during terminal stance to improve physical functional before and after TAA.

Assessment of district heating and cooling systems transition with respect to future changes in demand profiles and renewable energy supplies

District energy systems are about to shift towards closer temperature configurations, i.e. low-temperature district heating and high-temperature district cooling. Challenges and benefits of these transitions are mostly analyzed from a perspective of current energy demand and supply scenarios while the influence from future changes in these domains remains unknown. Based on a representative residential community in the Nordic district heating context, centralized district heating and cooling (DHC), ultra-low temperature district heating (ULTDH), and bi-directional fifth generation 5GDHC systems were assessed from technical, economical, and environmental aspects. Moreover, the applications of thermal energy storage (TES) and their roles in the future DHC systems were also investigated. The assessment was done by a generalized methodology framework, integrating the future changes, multiple operation scenarios modellings and system design optimizations. Results suggest that in the future low-energy building stock, the increased cooling demand makes the 5GDHC system the most economically attractive choice. In the supply side, with a 50% share of wind power in the future national grid, the electricity prices can make 5GDHC and ULTDHC either cost-saving or more expensive compared to the central DHC system dependent on if nuclear plants are decommissioned or not. Besides, with increasing power production from VRE, the limited application of TES for active shift of electricity demand is found when a system’s heat-to-power ratio is high. The methodology framework can be applied to similar systems to increase the understandings on system transitions.

Influence of chemical coatings on solar panel performance and snow accumulation

Solar panel performance can be impacted when panel surfaces are coated with substances like dust, dirt, snow, or ice that scatter and/or absorb light and may reduce efficiency. As a consequence, time and resources are required to clean solar panels during and after extreme weather events or whenever surface coating occurs. Treating solar panels with chemical coatings that shed materials may decrease the operating costs associated with solar panel maintenance and cleaning. This study investigates three commercial coatings for use as self-cleaning glass technologies. Optical and thermal properties (reflectivity, absorption, and transmission) are investigated for each coating as well as their surface wettability and particle size. Incoming solar radiation was continuously monitored and snow events were logged to estimate power production capabilities and surface accumulation for each panel. In terms of power output, the commercial coatings made little impact on overall power production compared to the control (uncoated) panels. This was attributable to the overall high transmission, low absorption, and low reflection of each of the commercial coatings, making their presence on the surface of solar panels have minimal impact besides to potentially shed snow While the coatings made no observable difference to increase power production compared to the control panels, the shedding results from video monitoring suggest both the hydrophilic or hydrophobic test coatings decreased snow accumulation to a greater extent than the control panels (uncoated). Controlling the wettability properties of the solar panel surfaces has the potential to limit snow accumulation when compared to uncoated panel surfaces.

Intermittent propulsion in largemouth bass, Micropterus salmoides, increases power production at low swimming speeds.

Locomotion dominates animal energy budgets, and selection should favour behaviours that minimize transportation costs. Recent fieldwork has altered our understanding of the preferred modes of locomotion in fishes. For instance, bluegill employ a sustainable intermittent swimming form with 2-3 tail beats alternating with short glides. Volitional swimming studies in the laboratory with bluegill suggest that the propulsive phase reflects a fixed-gear constraint on body-caudal-fin activity. Largemouth bass (Micropterus salmoides) also reportedly display intermittent swimming in the field. We examined swimming by bass in a static tank to quantify the parameters of volitional locomotion, including tailbeat frequency and glide duration, across a range of swimming speeds. We found that tailbeat frequency was not related to speed at low swimming speeds. Instead, speed was a function of glide duration between propulsive events, with glide duration decreasing as speed increased. The propulsive Strouhal number remained within the range that maximizes propulsive efficiency. We used muscle mechanics experiments to simulate power production by muscle operating under intermittent versus steady conditions. Workloop data suggest that intermittent activity allows fish to swim efficiently and avoid the drag-induced greater energetic cost of continuous swimming. The results offer support for a new perspective on fish locomotion: intermittent swimming is crucial to aerobic swimming energetics.

Super-rated operational concept for increased wind turbine power with energy storage

• New method of Region 3 operation proposed to increase power production. • Hydraulic transmission and energy storage proposed to decouple rotor and generator. • Super-rated operation has the potential to increase energy production by 23% • Capacity factor may increase from 53% to 66% without increasing generator size. • This system will require solving several hydraulic transmission engineering issues. A new super-rated method of wind turbine control is proposed for operation between rated and cut-out wind speeds, in conjunction with integrated energy storage, that may allow dramatically increased power capture as well as improved energy dispatchability without increasing turbine size or generator size. In the proposed system, a hydraulic transmission is used to decouple the wind turbine rotor from the electric generator, allowing for mechanical energy storage to be integrated into the system before the generator. Rather than the conventional Region 3 control, the new super-rated Region 3 + operation allows the rotor to generate additional power above the rated power limit and store that additional power for later regeneration. In this Region 3+ operation, the limit on operation is based on rotor thrust loads (instead of rotor power) so that power can increase with increasing wind speed. A case study with the NREL 5 MW reference turbine in steady Class I winds showed that super-rated operation could increase annual power production by 23% (including hydraulic transmission storage losses), without increasing mean out-of-plane blade loads, rotor size, or generator power. In addition, this new operation for this case increases the capacity factor from 53% to 66%, which increases power levelization. However, a wide array of component design issues must be addressed (especially for the hydraulic drivetrain) to determine if this potential can be realized.

An effective solution to boost generation from waves: Benefits of a hybrid energy storage system integration to wave energy converter in grid-connected systems

Background: Wave energy represents one of the most promising renewable energies due to its great theoretical potential. Nevertheless, the electrical compliance of grid-connected systems is a great issue nowadays, due to the highly stochastic nature of wave energy. Methods: In this paper, a Hybrid Energy Storage System (HESS) consisting of a Li-ion battery and a flywheel is coupled to a Wave Energy Converter (WEC) that operates in grid connected mode. The study is performed using real yearly wave power profiles relating to three different sites located along the European coasts. The Simultaneous Perturbation Stochastic Approximation (SPSA) principle is implemented as real-time power management strategy for HESS in wave energy conversion systems. Results: Obtained results demonstrate how the proposed HESS and the implementation of the SPSA power management coupled to a WEC allow a reduction of more than 80% of power oscillations at the Point of Common Coupling (PCC), while proving the robustness of the developed management strategy over the investigated sites. Moreover, the average energy penalty due to the HESS integration results slightly higher than 5% and battery solicitation is reduced by more than 64% with respect to the flywheel solicitation, contributing to extend its lifetime. Conclusions: HESS integration in renewable generation systems maximizes the WEC production while smoothing the power at the PCC. Specifically, flywheel-battery HESS together with the implemented power management strategy could provide a great flexibility in the view of increasing power production from waves, strongly mitigating the variability of this source while enhancing grid safety and stability.

Large eddy simulations of curled wakes from tilted wind turbines

One control strategy to increase power production in wind farms is angling wind turbine rotors, in order to steer wakes away from downwind turbines. Although rotor yaw is the most common approach to wake steering, tilting the rotor vertically to steer the wake downward can also increase total farm power. In this study, large eddy simulations of a 15 MW turbine are performed for rotor tilt angles of 0°, 15°, and 30° with below-rated turbulent inflow. Wake characteristics are analyzed, including using circulation to quantify the curled wake's counter-rotating vortex pair and quantifying wake shapes by fitting Legendre polynomials to wake edge polar coordinates. Tilting the rotor causes downward wake steering, wider and vertically compressed wake cross-sections, and stronger counter-rotating vortices. Although the wake velocity deficit recovers similarly for tilted and non-tilted wakes, the power available to a downwind rotor recovers faster because the tilted wake is steered away from the downwind rotor area and is replaced by high-speed air from above. This also causes higher effective wind shear across the downwind rotor. Additional simulations double the gap between the ground surface and the rotor bottom, which affects the wake geometry as well as the downwind power recovery and wind shear.

Optimizing of the installed capacity of hybrid renewable energy with a modified MPPT model

The lack of wind speed capacity and the emission of photons from sunlight are the problem in a hybrid system of photovoltaic (PV) panels and wind turbines. To overcome this shortcoming, the incremental conductance (IC) algorithm is applied that could control the converter work cycle and the switching of the buck boost therefore maximum efficiency of maximum power point tracking (MPPT) is reached. The operation of the PV-wind hybrid system, consisting of a 100 W PV array device and a 400 W wind subsystem, 12 V/100 Ah battery energy storage and LED, the PV-wind system requires a hybrid controller for battery charging and usage and load lamp and it’s conducted in experimental setup. The experimental has shown that an average increase in power generated was 38.8% compared to a single system of PV panels or a single wind turbine sub-system. Therefore, the potential opportunities for increasing power production in the tropics wheather could be carried out and applied with this model.

Great power comes at a high (locomotor) cost: the role of muscle fascicle length in the power versus economy performance trade-off.

Muscle design constraints preclude simultaneous specialization of the vertebrate locomotor system for explosive and economical force generation. The resulting performance trade-off between power and economy has been attributed primarily to individual differences in muscle fiber type composition. While certainly crucial for performance specialization, fiber type likely interacts with muscle architectural parameters, such as fascicle length, to produce this trade-off. Longer fascicles composed of more serial sarcomeres can achieve faster shortening velocities, allowing for greater power production. Long fascicles likely reduce economy, however, because more energy-consuming contractile units are activated for a given force production. We hypothesized that longer fascicles are associated with both increased power production and locomotor cost. In 11 power-trained and 13 endurance-trained recreational athletes, we measured (1) muscle fascicle length via ultrasound in the gastrocnemius lateralis, gastrocnemius medialis and vastus lateralis, (2) maximal power during cycling and countermovement jumps, and (3) running cost of transport. We estimated muscle fiber type non-invasively based on the pedaling rate at which maximal cycling power occurred. As predicted, longer gastrocnemius muscle fascicles were correlated with greater lower-body power production and cost of transport. Multiple regression analyses revealed that variability in maximal power was explained by fiber type (46% for cycling, 24% for jumping) and average fascicle length (20% for cycling, 13% for jumping), while average fascicle length accounted for 15% of the variation in cost of transport. These results suggest that, at least for certain muscles, fascicle length plays an important role in the power versus economy performance trade-off.

Optimization of PV array tilt angle for minimum levelized cost of energy

This paper studies the effects of PhotoVoltaic (PV) tilt angle variation over the cost efficiency of PV networks. The monthly modification of the tilt angle β conducted by this study, decreased the levelized cost of energy (LCOE), thus enhancing the system's economical status, by reducing its capital investment's payback period. The intended outcome of this work is twofold: it corresponds to a generalized novel mathematical model which enables the maximum number of PV panels to be fit into a square shaped area without any mutual shading, plus it investigates the monthly tilt angle values based on a specific selection, and their effects on the LCOE. The application of the obtained results (i.e., numerical values of β) has diminished both the LCOE as well as the power cost, while increasing power production for a PV system located in Tripoli-Lebanon (latitude: 34.38°), Belfort-France (latitude: 47.63°) and Tantan-Morocco (latitude: 28.38°).

Improved Microbial Fuel Cell Performance by Engineering E. coli for Enhanced Affinity to Gold

Microorganism affinity for surfaces can be controlled by introducing material binding motifs into proteins such as fimbrial tip and outer membrane proteins. Here, controlled surface affinity is used to manipulate and enhance electrical power production in a typical bioelectrochemical system, a microbial fuel cell (MFC). Specifically, gold-binding motifs of various affinity were introduced into two scaffolds in Escherichia coli: eCPX, a modified version of outer membrane protein X (OmpX), and FimH, the tip protein of the fimbriae. The behavior of these strains on gold electrodes was examined in small-scale (240 µL) MFCs and 40 mL U-tube MFCs. A clear correlation between the affinity of a strain for a gold surface and the peak voltage produced during MFC operation is shown in the small-scale MFCs; strains displaying peptides with high affinity for gold generate potentials greater than 80 mV while strains displaying peptides with minimal affinity to gold produce potentials around 30 mV. In the larger MFCs, E. coli strains with high affinity to gold exhibit power densities up to 0.27 mW/m2, approximately a 10-fold increase over unengineered strains lacking displayed peptides. Moreover, in the case of the modified FimH strains, this increased power production is sustained for five days.

Identification of wind turbine clusters for effective real time yaw control optimization

Control algorithms seeking to maximize wind plant power production may not require that all turbines communicate with each other for the purpose of coordinating an optimal control solution. In practice, an efficient and robust control solution may result by coordinating only turbines that are aerodynamically coupled through wake effects. The implementation of such control strategy would require information of which clusters of turbines are coupled in this way. As the wind changes direction, the clusters of coupled turbines may vary continuously within the array. Hence, in practical applications, the identification of these clusters has to be performed in real time in order to efficiently apply a coordinated control approach. Results from large eddy simulations of the flow over a wind farm array of 4 × 4 turbines are used to mimic Supervisory Control And Data Acquisition (SCADA) data needed for the cluster identification method and to evaluate the effectiveness of the yaw control applied to the identified clusters. Results show that our proposed method is effective in identifying turbine clusters, and that their optimization leads to a significant gain over the baseline. When the proposed method does not find clusters, the yaw optimization is ineffective in increasing the power of the array of turbines. This study provides a model-free method to select the turbines that should communicate with another to increase power production in real time. In addition, the analysis of the flow field provides general insights on the effect of the local induction, as well as of the wind farm blockage, on yaw optimization strategies.

Bidirectional speed range extension of DFIG‐based WECS with dynamic minimum dc‐bus voltage

Enlarging the speed range of wind turbines is an effective way to increase power production in low-frequency band wind which contains more energy and is very challenging for DFIG-based wind energy conversion system (WECS). The analysis shows that current controllability of the converter is the main factor limiting bidirectional speed range extension (BSRE). This problem can be solved by increasing dc-bus voltage, but a constant and high dc-bus voltage will increase the electrical stress and switching losses of the converter. This paper proposed a dynamic minimum dc-bus voltage (DMDCV) technique in which the dc-bus voltage can automatically adjust to enable the back-to-back voltage source converter to work in linear modulation mode at its minimum value, thus supporting BSRE while also achieving multiple goals including low electrical stress and low switching losses. Two implementation methods of DMDCV with and without modulation depth loop are proposed and discussed. The co-simulation results verified the feasibility of DMDCV and the advantages of BSRE in improving power generation.

Thermal Energy Estimation by In-situ Combustion in An Abandoned Oil Well

A downside of producing oil is that it can never be fully recovered. After the end of a well's life span, the residual oil remaining in the reservoir on average can be over 30%. This residual oil can be extracted using enhanced oil recovery techniques, one of which combusts the oil in the formation where the average reservoir temperature can increase to 400⁰C for light oil and over 600⁰C for heavy oils. This method can become a significant catalyst in solving Pakistan's energy need and increasing power production. This paper aims to estimate the thermal energy production by combusting this residual oil using in-situ combustion by air injection technique. The study deals with the well Kahi-01 located in the upper Indus basin having three formations. The main target is the Hangu formation and its three reservoir blocks. This formation is characterized by its high residual oil percentage of 76-85% at depths of about 1691-1741 meters. The results show that the highest thermal energy output among the three reservoirs was 34.6e6 Megajoules. The highest power output from the binary plant was 38.5e4 Kilowatt hour.