752 research outputs found
Supervisory model predictive control of building integrated renewable and low carbon energy systems
To reduce fossil fuel consumption and carbon emission in the building sector,
renewable and low carbon energy technologies are integrated in building energy
systems to supply all or part of the building energy demand. In this research, an
optimal supervisory controller is designed to optimize the operational cost and the
CO2 emission of the integrated energy systems. For this purpose, the building
energy system is defined and its boundary, components (subsystems), inputs and
outputs are identified. Then a mathematical model of the components is obtained.
For mathematical modelling of the energy system, a unified modelling method is
used. With this method, many different building energy systems can be modelled
uniformly. Two approaches are used; multi-period optimization and hybrid model
predictive control. In both approaches the optimization problem is deterministic, so
that at each time step the energy consumption of the building, and the available
renewable energy are perfectly predicted for the prediction horizon. The controller
is simulated in three different applications. In the first application the controller is
used for a system consisting of a micro-combined heat and power system with an
auxiliary boiler and a hot water storage tank. In this application the controller
reduces the operational cost and CO2 emission by 7.31 percent and 5.19 percent
respectively, with respect to the heat led operation. In the second application the
controller is used to control a farm electrification system consisting of PV panels, a
diesel generator and a battery bank. In this application the operational cost with
respect to the common load following strategy is reduced by 3.8 percent. In the
third application the controller is used to control a hybrid off-grid power system
consisting of PV panels, a battery bank, an electrolyzer, a hydrogen storage tank
and a fuel cell. In this application the controller maximizes the total stored energies
in the battery bank and the hydrogen storage tank
Artificial Neural Network and its Applications in the Energy Sector – An Overview
In order to realize the goal of optimal use of energy sources and cleaner environment at a minimal cost, researchers; field professionals; and industrialists
have identified the expediency of harnessing the computational benefits provided by artificial intelligence (AI) techniques. This article provides an
overview of AI, chronological blueprints of the emergence of artificial neural networks (ANNs) and some of its applications in the energy sector. This short survey reveals that despite the initial hiccups at the developmental stages of ANNs, ANN has tremendously evolved, is still evolving and have been found to be effective in handling highly complex problems even in the areas of modeling, control, and optimization, to mention a few
Dynamic Optimization Algorithms for Baseload Power Plant Cycling under Variable Renewable Energy
The growing deployment of variable renewable energy (VRE) sources, such as wind and solar, is mainly due to the decline in the cost of renewable technologies and the increase of societal and cultural pressures. Solar and wind power generation are also known to have zero marginal costs and fuel emissions during dispatch. Thereby, the VRE from these sources should be prioritized when available. However, the rapid deployment of VRE has heightened concerns regarding the challenges in the integration between fossil-fueled and renewable energy systems. The high variability introduced by the VRE as well as the limited alignment between demand and wind/solar power generation led to the increased need of dispatchable energy sources such as baseload natural gas- and coal-fired power plants to cycle their power outputs more often to reliably supply the net load. The increasing power plant cycling can introduce unexpected inefficiencies into the system that potentially incur higher costs, emissions, and wear-and-tear, as the power plants are no longer operating at their optimal design points.
In this dissertation, dynamic optimization algorithms are developed and implemented for baseload power plant cycling under VRE penetration. Specifically, two different dynamic optimization strategies are developed for the minute and hourly time scales of grid operation. The minute-level strategy is based on a mixed-integer linear programming (MILP) formulation for dynamic dispatch of energy systems, such as natural gas- and coal-fired power plants and sodium sulfur batteries, under VRE while considering power plant equipment health-related constraints. The hourly-level strategy is based on a Nonlinear Multi-objective dynamic real-time Predictive Optimization (NMPO) implemented in a supercritical pulverized coal-fired (SCPC) power plant with a postcombustion carbon capture system (CCS), considering economic and environmental objectives. Different strategies are employed and explored to improve computational tractability, such as mathematical reformulations, automatic differentiation (AD), and parallelization of a metaheuristic particle swarm optimization (PSO) component.
The MILP-based dynamic dispatch framework is used to simulate case studies considering different loads and renewable penetration levels for a suite of energy systems. The results show that grid flexibility is mostly provided by the natural gas power plant, while the batteries are used sparingly. Additionally, considering the post-optimization equivalent carbon analysis, the environmental performance is intrinsically connected to grid flexibility and the level of VRE penetration. The stress results reinforce the necessity of further considering and including equipment health-related constraints during dispatch.
The results of the NMPO successfully implemented for a large-scale SCPC-CCS show that the optimal compromise is automatically chosen from the Pareto front according to a set of weights for the objectives with minimal interaction between the framework and the decision maker. They also indicate that to setup the optimization thresholds and constraints, knowledge of the power system operations is essential. Finally, the market and carbon policies have an impact on the optimal compromise between the economic and environmental objectives
A Survey on Intelligent Optimization Approaches to Boiler Combustion Optimization
This paper reviews the researches on boiler combustion optimization, which is an important direction in the field of energy saving and emission reduction. Many methods have been used to deal with boiler combustion optimization, among which evolutionary computing (EC) techniques have recently gained much attention. However, the existing researches are not sufficiently focused and have not been summarized systematically. This has led to slow progress of research on boiler combustion optimization and has obstacles in the application. This paper introduces a comprehensive survey of the works of intelligent optimization algorithms in boiler combustion optimization and summarizes the contributions of different optimization algorithms. Finally, this paper discusses new research challenges and outlines future research directions, which can guide boiler combustion optimization to improve energy efficiency and reduce pollutant emission concentrations
Computational intelligence techniques for maximum energy efficiency of cogeneration processes based on internal combustion engines
153 p.El objeto de la tesis consiste en desarrollar estrategias de modelado y optimización del rendimiento energético de plantas de cogeneración basadas en motores de combustión interna (MCI), mediante el uso de las últimas tecnologías de inteligencia computacional. Con esta finalidad se cuenta con datos reales de una planta de cogeneración de energía, propiedad de la compañía EnergyWorks, situada en la localidad de Monzón (provincia de Huesca). La tesis se realiza en el marco de trabajo conjunto del Grupo de Diseño en Electrónica Digital (GDED) de la Universidad del País Vasco UPV/EHU y la empresa Optimitive S.L., empresa dedicada al software avanzado para la mejora en tiempo real de procesos industriale
On the analysis and design of genetic fuzzy controllers : An application to automatic generation control of large interconnected power systems using genetic fuzzy rule based systems.
Frequency Control of large interconnected power systems is governed by means
of Automatic Generation Control (AGC), which regulates the system frequency
and tie line power interchange at its nominal parameter set points. Conventional
approaches to AGC controller design is centered around the Proportional, Integral
and Derivative (PID) controller structures, which have found widespread
application within industry.
However, the dynamic changes experienced throughout the life cycle of power
systems have many contributing factors, in part attributed to unknown knowledge
of system behavior, neglected process dynamics and a limited knowledge of
system interactions, which makes modeling for AGC systems particularly trying
for conventional AGC controller design approaches.
Therefore, in this study, Genetic - Fuzzy controllers (GA - Fuzzy) are applied as
plausible candidates for Automatic Generation Controller design and application.
In GA - Fuzzy controllers, genetic algorithms which are based on the foundation
of evolutionary heuristics are used as a global search method for FLC design.
This is particularly motivated by the fact that Fuzzy controllers, especially where
there are large data sets, unknown process knowledge and insu cient expert data
available, FLC controller design proves to be a daunting task.
Therefore, this thesis explores the automatic design of FLC controllers through
evolutionary heuristics and applies the designed controller to the AGC problem
of large interconnected power systems. The design methodology followed is to
understand power system interactions through power plant modeling and the
simulation power plant models for the basis for AGC controller design.
It is shown in this study that the performance of the GA - Fuzzy controller
have favourable characteristics in terms of robust performance, robustness properties
and compares favorably with conventional AGC controller techniques. The
analysis of the GA - Fuzzy controller shows that problem formulation and chromosome
encoding of the problem search space forms an important prerequisite
for controller design by evolutionary methods.
Therefore the study concludes by stating that GA - Fuzzy controllers are plausible
for application within the power industry because of its desirable attributes
and that future work would include extending this research into areas of renewable
energy for study and application
Small-signal stability analysis of hybrid power system with quasi-oppositional sine cosine algorithm optimized fractional order PID controller
This article deals with the frequency instability problem of a hybrid energy power system (HEPS) coordinated with reheat thermal power plant. A stochastic optimization method called a sine-cosine algorithm (SCA) is, initially, applied for optimum tuning of fractional-order proportional-integral-derivative (FOPI-D) controller gains to balance the power generation and load profile. To accelerate the convergence mobility and escape the solutions from the local optimal level, quasi-oppositional based learning (Q-OBL) is integrated with SCA, which results in QOSCA. In this work, the PID-controller's derivative term is placed in the feedback path to avoid the set-point kick problem. A comparative assessment of the energy-storing devices is shown for analyzing the performances of the same in HEPS. The qualitative and quantitative evaluation of the results shows the best performance with the proposed QOSCA: FOPI-D controller compared to SCA-, grey wolf optimizer (GWO), and hyper-spherical search (HSS) optimized FOPI-D controller. It is also seen from the results that the proposed QOSCA: FOPI-D controller has satisfactory disturbance rejection ability and shows robust performance against parametric uncertainties and random load perturbation. The efficacy of the designed controller is confirmed by considering generation rate constraint, governor dead-band, and boiler dynamics effects
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