1,416 research outputs found
Synthesis of a compact wind profile using evolutionary algorithms for wind turbine system with storage
In this paper, the authors investigate two methodologies for synthesizing compact wind speed profiles by means of evolutionary algorithms. Such profile can be considered as input parameter in a prospective design process by optimization of a passive wind system with storage. Compact profiles are obtained by aggregating elementary patterns in order to fulfil some target indicators. The main difference between both methods presented in the paper is related to the choice of these indicators. In the first method, they are related to the storage system features while they only depend on wind features in the second
Battery sizing for a stand alone passive wind system using statistical techniques
In this paper, an original optimization method to jointly determine a reduced study term and an optimum battery sizing is investigated. This storage device is used to connect a passive wind turbine system with a stand alone network. A Weibull probability density function is used to generate different wind speed data. The passive wind system is composed of a wind turbine, a permanent magnet synchronous generator feeding a diode rectifier associated with a very low voltage DC battery bus. This study is essentially based on a similitude model applied on an 8 kW wind turbine system. Our reference model is taken from a 1.7 kW optimized system. The wind system generated power
and the load demand are coupled through a battery sized
using a statistical approach
Numerical Analysis of National Travel Data to Assess the Impact of UK Fleet Electrification
Accurately predicting the future power demand of electric vehicles is
important for developing policy and industrial strategy. Here we propose a
method to create a representative set of electricity demand profiles using
survey data from conventional vehicles. This is achieved by developing a model
which maps journey and vehicle parameters to an energy consumption, and
applying it individually to the entire data set. As a case study the National
Travel Survey was used to create a set of profiles representing an entirely
electric UK fleet of vehicles. This allowed prediction of the required
electricity demand and sizing of the necessary vehicle batteries. Also, by
inferring location information from the data, the effectiveness of various
charging strategies was assessed. These results will be useful in both National
planning, and as the inputs to further research on the impact of electric
vehicles
Optimized battery sizing for merchant solar PV capacity firming in different electricity markets
ComunicaciĂł presentada a IECON 2019 - 45th Annual Conference of the IEEE Industrial Electronics Society (Lisbon, Portugal 14-17 Oct. 2019)This work analyses the minimum energy capacity requirements to be demanded to battery energy storage systems used in megawatt-range merchant solar PV plants to grant capacity firming. The operation of such a plant is simulated (with a 2-minute time step, at three different locations of the Iberian Peninsula, and for different battery sizes) after solving a quadratic programming optimization problem. The control algorithm takes into account the irradiance forecast and the intraday electricity market configuration, which presents certain peculiarities in the Iberian region with regard to other European markets. The analysis has been performed in an annual basis and current irradiance measured values have been used
Reliability of Dynamic Load Scheduling with Solar Forecast Scenarios
This paper presents and evaluates the performance of an optimal scheduling
algorithm that selects the on/off combinations and timing of a finite set of
dynamic electric loads on the basis of short term predictions of the power
delivery from a photovoltaic source. In the algorithm for optimal scheduling,
each load is modeled with a dynamic power profile that may be different for on
and off switching. Optimal scheduling is achieved by the evaluation of a
user-specified criterion function with possible power constraints. The
scheduling algorithm exploits the use of a moving finite time horizon and the
resulting finite number of scheduling combinations to achieve real-time
computation of the optimal timing and switching of loads. The moving time
horizon in the proposed optimal scheduling algorithm provides an opportunity to
use short term (time moving) predictions of solar power based on advection of
clouds detected in sky images. Advection, persistence, and perfect forecast
scenarios are used as input to the load scheduling algorithm to elucidate the
effect of forecast errors on mis-scheduling. The advection forecast creates
less events where the load demand is greater than the available solar energy,
as compared to persistence. Increasing the decision horizon leads to increasing
error and decreased efficiency of the system, measured as the amount of power
consumed by the aggregate loads normalized by total solar power. For a
standalone system with a real forecast, energy reserves are necessary to
provide the excess energy required by mis-scheduled loads. A method for battery
sizing is proposed for future work.Comment: 6 pager, 4 figures, Syscon 201
Battery Sizing Optimization in Power Smoothing Applications
The main objective of this work was to determine the worth of installing an electrical battery in order to reduce peak power consumption. The importance of this question resides in the expensive terms of energy bills when using the maximum power level. If maximum power consumption decreases, it affects not only the revenues of maximum power level bills, but also results in important reductions at the source of the power. This way, the power of the transformer decreases, and other electrical elements can be removed from electrical installations. The authors studied the Spanish electrical system, and a particle swarm optimization (PSO) algorithm was used to model battery sizing in peak power smoothing applications for an electrical consumption point. This study proves that, despite not being entirely profitable at present due to current kWh prices, implanting a battery will definitely be an option to consider in the future when these prices come down.The authors were supported by the government of the Basque Country through research grants ELKARTEK 21/10: BASQNET: Estudio de nuevas técnicas de inteligencia artificial basadas en Deep Learning dirigidas a la optimización de procesos industriales
Propulsive Battery Packs Sizing for Aviation Applications
This thesis derives analytical methods for sizing the propulsive battery packs for designing an electric-driven aircraft. Lithium-Ion (Li-Ion) battery is the primary choice of battery cell chemistry in this thesis research due to its superior specific energy and market availability. The characteristics of Lithium-Ion battery cells are first determined and studied using experimental test results and manufacturers published data. Based on the design requirement to the battery system, the battery sizing will fall into one of the two sizing categories. The first category is power sizing, which requires the batteryâs ability to deliver full power demanded by the electric motor. The second category is endurance sizing, which requires the battery system to store sufficient energy for the required endurance. Both types of sizing are analytically derived. From the sizing result, capacity is used to determine the parallel connected battery cells. The required system voltage governs the series connected cells. A battery discharging simulation model is built to validate the sizing results
Storage Size Determination for Grid-Connected Photovoltaic Systems
In this paper, we study the problem of determining the size of battery
storage used in grid-connected photovoltaic (PV) systems. In our setting,
electricity is generated from PV and is used to supply the demand from loads.
Excess electricity generated from the PV can be stored in a battery to be used
later on, and electricity must be purchased from the electric grid if the PV
generation and battery discharging cannot meet the demand. Due to the
time-of-use electricity pricing, electricity can also be purchased from the
grid when the price is low, and be sold back to the grid when the price is
high. The objective is to minimize the cost associated with purchasing from (or
selling back to) the electric grid and the battery capacity loss while at the
same time satisfying the load and reducing the peak electricity purchase from
the grid. Essentially, the objective function depends on the chosen battery
size. We want to find a unique critical value (denoted as ) of the
battery size such that the total cost remains the same if the battery size is
larger than or equal to , and the cost is strictly larger if the
battery size is smaller than . We obtain a criterion for evaluating
the economic value of batteries compared to purchasing electricity from the
grid, propose lower and upper bounds on , and introduce an efficient
algorithm for calculating its value; these results are validated via
simulations.Comment: Submitted to IEEE Transactions on Sustainable Energy, June 2011; Jan
2012 (revision
Quasi-dynamic Load and Battery Sizing and Scheduling for Stand-Alone Solar System Using Mixed-integer Linear Programming
Considering the intermittency of renewable energy systems, a sizing and
scheduling model is proposed for a finite number of static electric loads. The
model objective is to maximize solar energy utilization with and without
storage. For the application of optimal load size selection, the energy
production of a solar photovoltaic is assumed to be consumed by a finite number
of discrete loads in an off-grid system using mixed-integer linear programming.
Additional constraints are battery charge and discharge limitations and minimum
uptime and downtime for each unit. For a certain solar power profile the model
outputs optimal unit size as well as the optimal scheduling for both units and
battery charge and discharge (if applicable). The impact of different solar
power profiles and minimum up and down time constraints on the optimal unit and
battery sizes are studied. The battery size required to achieve full solar
energy utilization decreases with the number of units and with increased
flexibility of the units (shorter on and off-time). A novel formulation is
introduced to model quasi-dynamic units that gradually start and stop and the
quasi-dynamic units increase solar energy utilization. The model can also be
applied to search for the optimal number of units for a given cost function.Comment: 6 pages, 3 figures, accepted at The IEEE Conference on Control
Applications (CCA
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