Showing papers on "Base load power plant published in 2011"

Comparing the Costs of Intermittent and Dispatchable Electricity Generating Technologies

Abstract: Economic evaluations of alternative electric generating technologies typically rely on comparisons between their expected life-cycle production costs per unit of electricity supplied. The standard life-cycle cost metric utilized is the “levelized cost” per MWh supplied. This paper demonstrates that this metric is inappropriate for comparing intermittent generating technologies like wind and solar with dispatchable generating technologies like nuclear, gas combined cycle, and coal. Levelized cost comparisons are a misleading metric for comparing intermittent and dispatchable generating technologies because they fail to take into account differences in the production profiles of intermittent and dispatchable generating technologies and the associated large variations in the market value of the electricity they supply. Levelized cost comparisons overvalue intermittent generating technologies compared to dispatchable base load generating technologies. They also overvalue wind generating technologies compared to solar generating technologies. Integrating differences in production profiles, the associated variations in the market value of the electricity supplied, and life-cycle costs associated with different generating technologies is necessary to provide meaningful comparisons between them. This market-based framework also has implications for the appropriate design of procurement auctions created to implement renewable energy procurement mandates, the efficient structure of production tax credits for renewable energy, and the evaluation of the additional costs of integrating intermittent generation into electric power networks.

Energy Harvesting From Hybrid Indoor Ambient Light and Thermal Energy Sources for Enhanced Performance of Wireless Sensor Nodes

Abstract: In this paper, a hybrid of indoor ambient light and thermal energy harvesting scheme that uses only one power management circuit to condition the combined output power harvested from both energy sources is proposed to extend the lifetime of the wireless sensor node. By avoiding the use of individual power management circuits for multiple energy sources, the number of components used in the hybrid energy harvesting (HEH) system is reduced and the system form factor, cost and power losses are thus reduced. An efficient microcontroller-based ultra low power management circuit with fixed voltage reference based maximum power point tracking is implemented with closed-loop voltage feedback control to ensure near maximum power transfer from the two energy sources to its connected electronic load over a wide range of operating conditions. From the experimental test results obtained, an average electrical power of 621 μW is harvested by the optimized HEH system at an average indoor solar irradiance of 1010 lux and a thermal gradient of 10 K, which is almost triple of that can be obtained with conventional single-source thermal energy harvesting method.

Integration of Vehicle-to-Grid in the Western Danish Power System

Abstract: The Danish power system is characterized by a large penetration of wind power. As the nature of the wind power is unpredictable, more balancing power is desired for a stable and reliable operation of the power system. The present balancing power in Denmark is provided mostly by the large central power plants followed by a number of decentralized combined heat and power units and connections from abroad. The future energy plans in Denmark aim for 50% wind power capacity integration which will replace many conventional large power plant units. The limited control and regulation power capabilities of large power plants in the future demands for new balancing solutions like vehicle-to-grid (V2G) systems. In this paper, aggregated electric vehicle (EV)-based battery storage representing a V2G system is modeled for the use in long-term dynamic power system simulations. Further, it is analyzed for power system regulation services for typical days with high and low wind production in the Western Danish power system. The results show that the regulation needs from conventional generators and the power deviations between West Denmark and Union for the Coordination of Electricity Transmission (UCTE) control areas are significantly minimized by the faster up and down regulation characteristics of the EV battery storage.

Reserve Requirement Impacts of Large-Scale Integration of Wind, Solar, and Ocean Wave Power Generation

Abstract: Many sources of renewable energy, including solar, wind, and ocean wave, offer significant advantages such as no fuel costs and no emissions from generation. However, in most cases these renewable power sources are variable and nondispatchable. The utility grid is already able to accommodate the variability of the load and some additional variability introduced by sources such as wind. However, at high penetration levels, the variability of renewable power sources can severely impact the utility reserve requirements. This paper presents an analysis of the interaction between the variability characteristics of the utility load, wind power generation, solar power generation, and ocean wave power generation. The results show that a diversified variable renewable energy mix can reduce the utility reserve requirement and help reduce the effects of variability.

Power Tower Technology Roadmap and Cost Reduction Plan

Abstract: Concentrating solar power (CSP) technologies continue to mature and are being deployed worldwide. Power towers will likely play an essential role in the future development of CSP due to their potential to provide dispatchable solar electricity at a low cost. This Power Tower Technology Roadmap has been developed by the U.S. Department of Energy (DOE) to describe the current technology, the improvement opportunities that exist for the technology, and the specific activities needed to reach the DOE programmatic target of providing competitively-priced electricity in the intermediate and baseload power markets by 2020. As a first step in developing this roadmap, a Power Tower Roadmap Workshop that included the tower industry, national laboratories, and DOE was held in March 2010. A number of technology improvement opportunities (TIOs) were identified at this workshop and separated into four categories associated with power tower subsystems: solar collector field, solar receiver, thermal energy storage, and power block/balance of plant. In this roadmap, the TIOs associated with power tower technologies are identified along with their respective impacts on the cost of delivered electricity. In addition, development timelines and estimated budgets to achieve cost reduction goals are presented. The roadmap does not present a single path formore » achieving these goals, but rather provides a process for evaluating a set of options from which DOE and industry can select to accelerate power tower R&D, cost reductions, and commercial deployment.« less

Smart Operation of Wind Turbines and Diesel Generators According to Economic Criteria

Abstract: This paper proposes an innovative system for Smart Grid (SG) management aiming at minimizing the total costs supported for carrying out the delivery of energy to consumers. These costs include the production costs of distributed generators, the cost of the power provided by the primary substation, and the cost associated with grid power losses. After a brief overview on the main SG aspects, this paper describes the proposed approach that makes use of an optimal power flow algorithm and the active management schemes. The efficiency of the method is verified on a distribution system comprising wind turbines and diesel generators, considering the time-varying characteristics of the load demand and wind power generation.

Optimal energy storage control policies for the smart power grid

Abstract: Electric energy storage devices are prime candidates for demand load management in the smart power grid. In this work, we address the optimal energy storage control problem from the side of the utility operator. The operator controller receives power demand requests with different power requirements and durations that are activated immediately. The controller has access to one energy storage device of finite capacity. The objective is to devise an energy storage control policy that minimizes long-term average grid operational cost. The cost is a convex function of instantaneous power demand that is satisfied from the grid, and it reflects the fact that each additional unit of power needed to serve demands is more expensive as the demand load increases. For the online dynamic control problem, we derive a threshold-based control policy that attempts to maintain balanced power consumption from the grid at all times, in the presence of continual generation and completion of demands. The policy adaptively performs charging or discharging of the storage device. The former increases power consumption from the grid and the latter satisfies part of the grid demand from the stored energy. We prove that the policy is asymptotically optimal as the storage capacity becomes large, and we numerically show that it performs very well even for finite capacity. The off-line problem over a finite time horizon that assumes a priori known power consumption to be satisfied at all times, is formulated and solved with Dynamic Programming. Finally, we show that the model, approach and structure of the optimal policy can be extended to also account for a renewable source that feeds the storage device.

Optimization of pv/wind/ micro-hydro/diesel hybrid power system in homer for the study area

Abstract: A large proportion of the world's population lives in remote rural areas that are geographically isolated and sparsely populated. This paper proposed a hybrid power generation system suitable for remote area application. The concept of hybridizing renewable energy sources is that the base load is to be covered by largest and firmly available renewable source(s) and other intermittent source(s) should augment the base load to cover the peak load of an isolated mini electric grid system. The study is based on modeling, simulation and optimization of renewable energy system in rural area in Sundargarh district of Orissa state, India. The model has designed to provide an optimal system conFigureuration based on hour-by-hour data for energy availability and demands. Various renewable/alternative energy sources, energy storage and their applicability in terms of cost and performance are discussed. The homer software is used to study and design the proposed hybrid alternative energy power system model. The Sensitivity analysis was carried out using Homer program. Based on simulation results, it has been found that renewable/alternative energy sources will replace the conventional energy sources and would be a feasible solution for distribution of electric power for stand alone applications at remote and distant locations.

Probabilistic Load Flow Including Wind Power Generation

Abstract: In this paper, a procedure is established for calculating the load flow probability density function in an electrical power network, taking into account the presence of wind power generation. The probability density function of the power injected in the network by a wind turbine is first obtained by utilizing a quadratic approximation of its power curve. With this model, the DC power flow of a network is calculated, considering the probabilistic nature of the power injected or consumed by the generators and the loads.

A Design Methodology for Smart LED Lighting Systems Powered By Weakly Regulated Renewable Power Grids

Abstract: The increasing use of intermittent renewable energy sources to decarbonize electric power generation is expected to introduce dynamic instability to the mains. This situation is of particular concern for mini-grids or isolated grids in which wind and/or solar power sources are the dominant or the sole power sources. In this paper, we utilize the photo-electro-thermal theory to develop a design methodology for LED lighting systems for weakly regulated voltage sources, with the objectives of minimizing the fluctuation of the human luminous perception and adopting reliable LED driver with long lifetime and robustness against extreme weather conditions. The proposed LED system, practically verified in a 10 kVA small power grid driven by an ac voltage source and a wind energy simulator, can be considered as a smart load with its load demand following the power generation. A typical swing of 40 V in the mains will cause only 15% actual light variation in a 132 W LED system when compared with 40% change in 150 W high-pressure-sodium lamp system. The design methodology enables future large-scale LED systems to be designed as a new generation of smart loads that can adapt to the voltage and power fluctuations arising from the intermittent nature of renewable energy sources.

Efficient Storage Capacity in Power Systems with Thermal and Renewable Generation

Abstract: Power systems with high shares of wind and solar power have to balance their intermittent nature. Pumped‐hydro storage plants can provide the required flexibility, while thermal backup plants offer an alternative. This paper proposes a model based on peak‐load‐pricing theory to describe the efficient technology portfolio. Drawing on a load duration curve, we derive the efficient storage capacity and discuss its dependence on cost parameters. It is shown that renewable generation affects the efficient storage capacity by changing the shape of the residual load duration curve, while limited time periods with renewable generation in excess of load do not necessarily affect the level of storage. A case study for Germany applies the model and highlights the impact of CO2 prices on storage efficiency.

On the minimization of power consumption in base stations using on/off power amplifiers

Abstract: Using energy generated with fossil fuel causes global warming due to the greenhouse effect, which threatens our environment One of the challenges for New Generation Networks (NGN) is then the reduction of energy consumption, in particular at the BSs (Base Stations) which use about 85% of the total network energy We contribute to the research with a mathematical model that calculates the total power consumption of a BS and enlightens the way to minimize it First, we analyze the power consumed at every different component of the BS Second, based on the cost incurred in turning off the BS's power amplifiers, we show how to decide whether it is convenient to keep the BS idle during those intervals in which no traffic has to be sent, or to turn off the amplifiers Our model is evaluated by means of numerical examples, and shows that interesting power gain can be obtained under a large spectrum of load conditions

Stochastic MPC for real-time market-based optimal power dispatch

Abstract: We formulate the problem of dynamic, real-time optimal power dispatch for electric power systems consisting of conventional power generators, intermittent generators from renewable sources, energy storage systems and price-inelastic loads. The generation company managing the power system can place bids on the real-time energy market (the so-called regulating market) in order to balance its loads and/or to make profit. Prices, demands and intermittent power injections are considered to be stochastic processes and the goal is to compute power injections for the conventional power generators, charge and discharge levels for the storage units and exchanged power with the rest of the grid that minimize operating and trading costs. We propose a scenario-based stochastic model predictive control algorithm to solve the real-time market-based optimal power dispatch problem.

Managing renewable power generation

Abstract: A power delivery rate from a renewable power source to a load is managed by determining, by processing circuitry, a change in a power generation rate, determining, by the processing circuitry, whether the change in the power generation rate exceeds a limit, and then, adjusting, by control circuitry, a power transfer rate to or from a power storage device, such that the adjusting is sufficient to prevent the power delivery rate from exceeding the limit.

Currents of change

Abstract: The power systems in Denmark, Portugal, Spain, Ireland, and Germany have some of the highest wind penetrations in the world, as shown in the paper. In this article, the situations of five countries with high wind penetration are briefly presented, with special emphasis given to their future needs with respect to accommodating targeted wind power amounts. The final section provides an overview of offshore grid developments and plans in Europe.

Optimal power flow with distributed energy storage dynamics

Abstract: Restructuring of the electric power industry along with mandates to integrate renewable energy sources is introducing new challenges for electric power systems and the power grid. Intermittent power sources in particular require mitigation strategies in order to maintain consistent power on the electric grid. We investigate distributed energy storage as one such strategy. Our model for optimal power flow consists of simple charge/discharge dynamics for energy storage collocated with load and/or generation buses cast as a finite-time optimal control problem. We illustrate the effects of energy storage using a modified version of the IEEE 14 bus benchmark example along with time-varying demand profiles. We use both time-invariant and demand based cost functions. The addition of energy storage along with demand based cost functions significantly reduces the generation costs and flattens the generation profiles.

A family of non-isolated three-port converters for stand-alone renewable power system

Abstract: The stand-alone renewable power system with three-port converter features high efficiency, high power density, high reliability, small size and low cost. Analyzing power flow among the ports, it is found that a three-port converter (TPC) can be treated as a dual-output converter from the point of primary source and as a dual-input converter from the load, respectively. Begin with reconstructing the power flow paths, both combined and integrated non-isolated TPC (NI-TPC) topologies are proposed. The topology generation principles and methods are given with a series of NI-TPC topologies presented. The TPCs developed features single stage conversion between any two of the three ports. Operational mode analysis and experimental results of one of the proposed NI-TPC are given to verify the analysis.

Flexible and cost efficient power consumption using economic MPC a supermarket refrigeration benchmark

Abstract: Supermarket refrigeration consumes substantial amounts of energy. However due to the thermal capacity of the refrigerated goods, parts of the cooling capacity delivered can be shifted in time without deteriorating the food quality. In this paper we introduce a novel economic-optimizing MPC scheme that reduces operating costs by utilizing the thermal storage capabilities. In the study we specifically address advantages coming from daily variations in outdoor temperature and electricity prices but other aspects such as peak load reduction are also considered. An important contribution of this paper is also the formulation of a new cost function for our proposed power management system. This means the refrigeration system is enabled to contribute with ancillary services to the balancing power market. Since significant amounts of regulating power are needed for a higher penetration of intermittent renewable energy sources such as wind turbines, this feature will be in high demand in a future intelligent power grid (Smart Grid). Our perspective is seen from the refrigeration system but, as we demonstrate, the involvement in the balancing market can be economically beneficial for the system itself, while delivering crucial services to the Smart Grid. We simulate the system using models validated against data from real supermarkets as well as weather data and spot and regulating power prices from the Nordic power market.

Design of a Multi-time Scale Coordinated Active Power Dispatching System for Accommodating Large Scale Wind Power Penetration

Abstract: Large scale wind power has posed a great challenge for the power system dispatching mode and technology.By analyzing the characteristics of the predicting accuracy of wind power that increases level by level with different time scales and the inherent features of active power dispatch,a multi-time scale coordinated automatic power dispatching mode and its key technologies are proposed.In this mode,the deviations left over by the preceding level are corrected by the next level based on the idea of "multi-level coordination,level by level refining".First,the framework and general idea of this system is described.Second,the methods of evaluating the generation trend are proposed including such problems as the ideal generation output model,extended short-term forecasting,ultra short-term forecasting and decomposition of the load curve.Third,the online rolling power scheduling model and its relationship with the day-ahead schedule,as well as the real-time power dispatching model using the waste wind minimum as the objective,and its relationship with the wind farm dispatch are presented.Finally,the application effects of an actual system are illustrated.