Showing papers on "Base load power plant published in 2008"

Microgrids management

Abstract: The environmental and economical benefits of the microgrid and consequently its acceptability and degree of proliferation in the utility power industry, are primarily determined by the envisioned controller capabilities and the operational features. Depending on the type and depth of penetration of distributed energy resource (DER) units, load characteristics and power quality constraints, and market participation strategies, the required control and operational strategies of a microgrid can be significantly, and even conceptually, different than those of the conventional power systems.

Technical challenges associated with the integration of wind power into power systems

Abstract: Wind power is going through a very rapid development. It is among the fastest growing power sources in the world, the technology is being developed rapidly and wind power is supplying significant shares of the energy in large regions. The integration of wind power in the power system is now an issue in order to optimize the utilization of the resource and to continue the high rate of installation of wind generating capacity, which is necessary so as to achieve the goals of sustainability and security of supply. This paper presents the main technical challenges that are associated with the integration of wind power into power systems. These challenges include effects of wind power on the power system, the power system operating cost, power quality, power imbalances, power system dynamics, and impacts on transmission planning. The main conclusion is that wind power's impacts on system operating costs are small at low wind penetrations (about 5% or less). At higher wind penetrations, the impact will be higher, although current results suggest the impact remains moderate with penetrations approaching 20%. In addition, the paper presents the technology and expectations of wind forecasting as well as cases where wind power curtailment could arise. Future research directions for a better understanding of the factors influencing the increased integration of wind power into power systems are also provided.

Dc-link voltage control of full power converter for wind generator operating in weak grid systems

Abstract: In this paper, permanent magnet wind generator with full power converter is investigated in weak grid systems, where the dc-link voltage needs to be controlled from the generator side instead of grid side. When wind power takes a large portion of grid power, it needs to help grid to regulate the voltage and frequency. To achieve this, a variable step search algorithm based on the derivation of the electro-mechanical dynamic model describing the wind turbine is proposed, which enables the wind generator output power to match the load power, thus keeping the dc-link voltage regulated. Based on the non-linearity and different slopes of wind power curve, the controller is designed specifically for different sectors. A back-EMF observer based sensor-less generator control is adopted here to regulate the generator speed. Simulation is built up with a 10 kW wind power generator system and a reduced-scale 1.5 kW system experiment is also carried out in the condition of load power step change and wind speed change. Both simulation and experimental results validate the effectiveness of the proposed control scheme, where the dc-link voltage can be kept stable by adjusting the wind generator speed.

Estimating the impacts of wind power on power systems—summary of IEA Wind collaboration

Abstract: Adding wind power to power systems will have beneficial impacts by reducing the emissions of electricity production and reducing the operational costs of the power system as less fuel is consumed in conventional power plants. Wind power will also have a capacity value to a power system. However, possible negative impacts will have to be assessed to make sure that they will only offset a small part of the benefits and also to ensure the security of the power system operation. An international forum for the exchange of knowledge of power system impacts of wind power has been formed under the IEA Implementing Agreement on Wind Energy. The Task ‘Design and Operation of Power Systems with Large Amounts of Wind Power’ is analyzing existing case studies from different power systems. There are a multitude of studies completed and ongoing related to the cost of wind integration. However, the results are not easy to compare. This paper describes the general issues of wind power impacts on power systems and presents a comparison of results from ten case studies on increased balancing needs due to wind power.

Intermittent renewable generation and the cost of maintaining power system reliability

Abstract: There have been attempts, using various approaches, to assess the additional cost of running an electricity system when intermittent renewable generation is used to provide a significant proportion of the energy. The key issues are the difference, in statistical terms, between the resource availability of the intermittent source and conventional generation and the contribution the intermittent source can make to meet the system peak demand while maintaining system reliability. There is considerable agreement over the capacity credits that can be attributed to renewable energy sources, that is the amount of conventional capacity that renewables can reliably displace, yet the implications for costs have proved more controversial. Approaches to calculate changes in overall system cost are examined and an expression for the additional cost that intermittent generation imposes on a system that is attributable to its intermittent nature is identified. Further, it is shown that this expression can be reconciled with approaches that look at intermittent renewables on a stand-alone basis and factor in the additional costs of 'standby' capacity. It is shown that the main source of divergence between estimates of the cost of intermittency is the load factor implicitly assumed for the conventional plant used as a reference. There is only one consistent way to impute the costs of intermittency when the unit cost of intermittent plant is being compared with that of baseload generation plant.

Method of start up at least a part of a wind power plant, wind power plant and use of the wind power plant

Abstract: A wind power plant and a method of start up at least a part of a wind power plant connected to an external grid substantially without any energy delivered from the external grid for the start up is provided. The wind power plant having a plurality of wind turbines and at least one power source connected to at least one of the wind turbines in order to start the wind turbine while isolated from the remaining wind turbines. The started wind turbine may then supply power in order to start further wind turbines. Power may be delivered to the grid from the started wind turbines.

Status of Geothermal Exploration in Kenya and Future Plans for Its Development

Abstract: Kenya is endowed with vast geothermal potential along the world famous East African Rift valley that transects the country from north to south. Exploration reveals that geothermal potential exceeds 4,000 MWe and is capable of meeting all of Kenyas electricity needs over the next 20 years. Out of this potential, only 130 MWe is currently generated at the Greater Olkaria geothermal field. KenGen in collaboration with the Ministry of Energy of the Government of Kenya has undertaken detailed surface studies of most of the prospects in the Kenya rift, which comprises Suswa, Longonot, Olkaria, Eburru, Menengai, Lakes Bogoria and Baringo, Korosi and Paka volcanic fields. The Least Cost Power Development Plan (2008-2028) prepared by the Government of Kenya indicates that geothermal plants have the lowest unit cost and therefore suitable for base load and thus, recommended for additional expansion. Electric power demand in Kenya currently stands at over 8% annually. In order to meet the anticipated growth in demand, The Kenya Electricity Generating Company (KenGen) has embarked on an ambitious generation expansion plan to install additional 1,260 MW of electric power by 2018 from geothermal sources. The planned geothermal developments require over 300 production and 60 re-injection wells to be drilled in the next ten (10) years and about 10 large power stations of about 140 MWe each to be built at a total cost of over US$ 5 billion inclusive of wells and steam gathering system. Kenya Electricity Generating Company Limited (KenGen) is a public company under the Ministry of Energy of Kenya and is listed in the Nairobi Stock Exchange. The Government owns 70% of the Company while the public owns the remaining 30%. The Company currently has an installed electric plant capacity of 1005 MWe, which comprises a mix of hydro, geothermal, thermal, wind, gas turbines and diesel power generators. KenGen currently produces about 80% of the total interconnected power supply in Kenya. Kenya has a demand growth of 8%. The growth is driven by increased consumption from existing customers of 5% and new customers account for the 3%. However, installed capacity has not increased to match the demand growth thus emergency power has been procured to satisfy peak demand. The Least Cost Power Development Plan (2008-2028) prepared by the Government of Kenya indicates that geothermal plants have the lowest unit cost and therefore suitable for base load and thus, recommended for additional expansion.

Optimization of the Regional Spatial Distribution of Wind Power Plants to Minimize the Variability of Wind Energy Input into Power Supply Systems

Abstract: In contrast to conventional power generation, wind energy is not a controllable resource because of its stochastic nature, and the cumulative energy input of several wind power plants into the electric grid may cause undesired fluctuations in the power system. To mitigate this effect, the authors propose a procedure to calculate the optimal allocation of wind power plants over an extended territory to obtain a low temporal variability without penalizing too much the overall wind energy input into the power system. The procedure has been tested over Corsica (France), the fourth largest island in the Mediterranean Basin. The regional power supply system of Corsica could be sensitive to large fluctuations in power generation like wind power swings caused by the wind intermittency. The proposed methodology is based on the analysis of wind measurements from 10 anemometric stations located along the shoreline of the island, where most of the population resides, in a reasonably even distribution. First ...

Power electronics control of wind energy in distributed power systems

Abstract: The global electrical energy consumption is still rising and there is an urgent demand to increase the power capacity. It is expected that the power capacity has to be doubled within 20 years. The production, distribution and use of energy should be as efficient as possible and incentives to save energy at the end-user should also be set up. Deregulation of energy has in the past lowered the investment in larger power plants, which means the need for new electrical power sources will be high in the near future. Two major technologies will play important roles to solve the future problems. One is to change the electrical power production sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. The other is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss the most emerging renewable energy sources, wind energy, which by means of power electronics are changing from being a minor energy source to be acting as an important power source in the energy system. Power electronics is the enabling technology and the presentation will cover the development in wind turbine technology from kW to MW, discuss which power electronic solutions are most feasible and used today.

Virtual power plant field experiment using 10 micro-CHP units at consumer premises

Abstract: It is expected that mu-CHP units in households will penetrate the market in the Netherlands at high speed in the coming few years. As a result, the consuming households will then also produce electricity, which makes them suitable for local management of the grid. Using ICT, the mu-CHPs can be clustered in a virtual power plant (VPP). One application of such a VPP is the reduction of peak loads in the local substation by shifting the mu-CHP operation to moments when there is a large demand in electricity. In a field test conducted by ECN and Gasunie, it was found that a cluster of 10 households, each equipped with a mu-CHP is able to reduce the substation peak load with 30-50% without infringement of the user comfort.

Comparison of electricity generation costs

Abstract: The economical competitiveness of various power plant alternatives is compared. The comparison comprises merely electricity producing power plants. Combined heat and power (CHP) producing power will cover part of the future power deficit in Finland, but also condensing power plants for base load production will be needed. The following types of power plants are studied: nuclear power plant, combined cycle gas turbine plant, coal-fired condensing power plant, peat-fired condensing power plant, wood-fired condensing power plant and wind power plant. The calculations are carried out by using the annuity method with a real interest rate of 5 % per annum and with a fixed price level as of January 2008. With the annual peak load utilization time of 8000 hours (corresponding to a load factor of 91,3 %) the production costs would be for nuclear electricity 35,0 €/MWh, for gas based electricity 59,2 €/MWh and for coal based electricity 64,4 €/MWh, when using a price of 23 €/tonCO2 for the carbon dioxide emission trading. Without emission trading the production cost of gas electricity is 51,2 €/MWh and that of coal electricity 45,7 €/MWh and nuclear remains the same (35,0 €/MWh) In order to study the impact of changes in the input data, a sensitivity analysis has been carried out. It reveals that the advantage of the nuclear power is quite clear. E.g. the nuclear electricity is rather insensitive to the changes of nuclear fuel price, whereas for natural gas alternative the rising trend of gas price causes the greatest risk. Furthermore, increase of emission trading price improves the competitiveness of the nuclear alternative. The competitiveness and payback of the nuclear power investment is studied also as such by using various electricity market prices for determining the revenues generated by the investment. The profitability of the investment is excellent, if the market price of electricity is 50 €/MWh or more.

Hybrid wind turbine system, apparatus and method

Abstract: A wind turbine assembly and method capable of providing a total firm power output. There is a wind power section which delivers non-firm power from the wind turbine to a generator section. Then there is also an auxiliary power section which is capable of providing firm power to the same generator section. This can operate in three operating modes, namely an only wind power mode, an only auxiliary power mode, and a combined wind power and auxiliary power mode.

Studies on voltage fluctuation in the integration of wind power plants using probabilistic load flow

Abstract: A new method for analyzing voltage fluctuation in the integration of wind power plants using probabilistic load flow is presented in this paper. This method takes many probabilistic factors into consideration such as the generation output variations of wind power plants, load fluctuations, generator outages and branch outages, and then by probabilistic load flow calculation, not only the probabilistic distributions of nodal voltages are obtained, but also voltage fluctuations can be demonstrated. Moreover, the proposed method may help the optimization of reactive power compensation at wind power plants. In addition, a three-parameter Weibull distribution model that takes the location parameter into account is proposed to describe wind speed random fluctuation. Compared with the two-parameter Weibull distribution model, the impact of high speed wind on the power output of the wind turbine is considered by the presented model. Therefore, more satisfactory results can be obtained in the evaluation. The computation results of the IEEE RTS-24 test system with a wind power plant not only show the effectiveness of this method but also indicate that it can provide instructions on reactive power compensation, the location of a wind power plant, generation scheduling and dispatching. As a result, it is a useful tool for electrical engineers to study the voltage quality of the grid and choose a suitable integration location for a wind farm.

Economic Incentive for Intermittent Operation of Air Separation Plants with Variable Power Costs

Abstract: This article presents a simplified economic analysis of the effect of hourly variations in power costs on energy and capital costs of cryogenic air separation plants. The objective is to see what r...

Power supply control system and method of controlling the same

Abstract: PROBLEM TO BE SOLVED: To provide a power supply control system that effectively alleviates tight conditions of power demand and supply. SOLUTION: The power supply control system is such that an electric power supply overall control server 5 mounted in an area power supply apparatus 3 collects information on the respective operating states of a large number of electrical appliances 9 through an external data network 6; compares, for determining the presence of a tight state of power demand and supply, the available capacity of power to be supplied and the total power consumption of the large number of electric appliances under a normal operation, with an available amount of power supply of the area power supply apparatus, and if the state of power demand and supply is found to be tight, transmits IP addresses of IPv6 identifying the large number of electrical appliances under operation and operational mode alteration instructions to power-saving mode to the data network. In the meantime, upon receipt of the operational mode alteration instructions to their respective addresses from the electric power supply overall control server by power controllers 11 through the data network, the large number of respective electrical appliances, control altering of the respective electrical appliances to the power saving mode. COPYRIGHT: (C)2009,JPO&INPIT

Power supply/demand control program, power supply/demand controller, and power supply/demand control system

Abstract: PROBLEM TO BE SOLVED: To suppress reverse power flow to a substation from each consumer. SOLUTION: In a consumer in which a distributed power supply and a storage battery are provided, a supply/demand IF measures a power flow in a power receiving point, calculates a target value which is an upper limit value of the reverse power flow in the power receiving point and, when the reverse power flow exceeding the target value is detected, charges electric power generated by the distributed power supply in the storage battery. As the target value, for example, the moving average of the measured reverse power flow is used. COPYRIGHT: (C)2010,JPO&INPIT

Valuation of Reserve Services

Abstract: Spinning reserve is idle capacity connected to the system with the purpose of balancing power demand and supply in real-time and ensuring reliable system operations in the case of equipment outages. The reserve has an economic value since it reduces the load shedding costs. This value is impacted by the reliability and dynamic characteristics of system components, the variability of the load from its forecast, the system operation policies, and economic aspects such as the risk preferences of the demand. In this paper, we take into account all these aspects to estimate the reserve value. The results require little computational effort, and are useful in the development of reserve demand functions and optimal reserve requirements.

Drive friendly

Abstract: Fuel cells are good energy sources to provide reliable power at steady state and supercapacitor energy storage devices can advance the load following characteristics of a fuel cell by providing a stronger power response to changes in system loading. During motor starts/stops or other considerable steps in load, the super-capacitors provide the balance of energy needed during the temporary load transition periods and also absorb excess energy from the generator source (motor braking). Adding supercapacitor energy storage to distributed power systems improves power quality and efficiency and reduces capital expenses by allowing the systems to be sized more closely to the steady-state power requirements rather than over-sizing the main generator to meet transient loading requirements.

Dc power control to maximize battery charging time

Abstract: Systems and methods are provided for managing the batteries and the power source as a single combined output to power the load, allowing the system to use power source with reduced maximum power output, reducing system cost and complexity. Furthermore, the switch matrix controller efficiently and dynamically manages the internal power transfer to minimize the charging/discharging cycle of the batteries while ensuring that the power source and the batteries meet changing load power demand. Finally, maximizing charging time and having independent control of each battery increase power efficiency, prolong the operational life of the battery, and increase overall system life.

Load Shifting Agents for Automated Demand Side Management in Micro Energy Grids

Abstract: This paper describes a novel approach for the automated management of micro energy grids. In particular a market based resource allocation mechanism is used to control energy generators and consumers within a micro energy grid. This approach requires energy consumers (producers) to buy (sell) their energy demands (supplies) through a specialized electronic auction platform. But as manually negotiating all energy demands and supplies on such a market is a tedious task, its automation is highly desirable and thus leads to the main contribution of this paper: The automation of the demand side bidding process through electronic bidding agents, which are equipped with an intelligent buying strategy that allows them to dynamically react to market changes and adapt their bidding behavior accordingly. More precisely, the agents are able to shift energy demand within certain boundaries from (expensive) peak hours to those times of the day where energy demand and thus energy prices are lower in order to minimize their cost. Moreover, as our results show, this behavior leads to a smoothed load curve for the whole system, i.e. demand peaks are reduced while base load increases.

Impact of wind power on stability of offshore platform power systems

Abstract: Wind turbine generator systems can be including in conventional isolated power systems such as offshore oil platform power systems to significantly lower operating costs due to increased fuel savings. It is quite evident that limitations in the wind energy and its intermittent behavior degrade system stability. Wind power penetration can significantly reduce the system fuel costs but can also have considerable impact on the system stability. In this paper, the stability assessment of an isolated offshore oil platform power system with wind power based PSCAD/EMTDC is presented. The simulation results show that the wind power expansion in the isolated offshore oil platform power system with three synchronous generators driven by gas turbines can keep the system voltage and frequency stability at a desired level. Grid connection experiments between the offshore oil platform power system and wind turbine generators supported by CNOOC will prove the impact of connection of wind power on the voltage and frequency stability can be accepted lately.

Power source system, power supply control method for the power source system, power supply control program for the power source system, and computer-readable recording medium with the power supply control program recorded thereon

Abstract: The present invention provides a power source system that increases the power supply capacity of a power source device and continuously supplies the power necessary for a load device when a power source device stops. A control unit has a state quantity setting unit that sets a first target state quantity indicating a state of charge of the power storage device that is to be a target value when charge and discharge of the power storage device are controlled. When the power source device stops, the state quantity setting unit can change the first target state quantity to a second target state quantity that is to be a target value exceeding the first target state quantity and can increase the target state quantity of the power storage device. As a result, when the power source device stops, charge and discharge of the power storage device are controlled on the basis of the target state quantity exceeding that during the operation of the power source device. Therefore, the state of charge of the power storage device can be improved over that during the operation of the power source device. As a result, the power supply capacity of the power source device can be increased and the power necessary for the load device can be continuously supplied, in place of the power source device.

Review of Ultracapacitor Technology and its Applications

Abstract: An efficient electrical energy storage media are essential and are considered as a short term and an enabling infrastructure power technology. Energy storage technologies do not represent energy sources but they provide value added benefits to improve system stability, power quality and reliability of supply. As batteries technologies are low cost ,well established and widely used technology offer disadvantages like volume, weight, poor power density, high internal resistance, poor transient response, they are not suitable for some transient application or where volume and size are an important issue. On the other hand due to advancement in the material and other technology, Ultracapacitors offers high power density, fast transient response, low Wight, low volume and low internal resistance which make them suitable for pulsed load application. In this paper we will review some of the present application of the Ultracapacitor(UC) in the field of low power and high power applications like telecommunication devices, automatic meter reading system, load leveling on the electrical power system, maintaining continuity of power during outages, improving profitability in high energy system, enhance transmission capacity of the transmission grid in high power application, various power quality and backup related uses such as UPS system and power stabilization, to improve reliability of wind turbine pitch system. Simple ultracapcitor and battery model with pulse load is simulated in MATLAB-SIMULINK without and with DC to DC buck boost converter to prove ultracapacitor as a peak power supply device. Index Terms—Equivalent series resistance (ESR), Ultracapacitor (UC), UPS.