04-09-2012, 01:17 PM
DISTRIBUTED GENERATION
DISTRIBUTED.pdf (Size: 614.55 KB / Downloads: 86)
ABSTRACT
Increased demands on the nation's electrical power systems and incidences of electricity shortages, power quality problems, rolling blackouts, and electricity price spikes have caused many utility customers to seek other sources of high-quality, reliable electricity. In such a scenario , the approach of distributed generation , which involves the production of electricity close to the end users of power , has come up as an alternative to , or an enhancement of the traditional electrical power grid. Distributed generation may be defined as the installation and operation of small modular power generating technologies that can be combined with energy management and storage systems. This system can employ a range of technologies – from renewable to non-renewable and can operate in either a connected grid or in off-grid mode. The technologies which adopt renewable resources have struck a chord with the environmental advocates as well. Thus, this approach has been gaining popularity across the world, from the modernised cities of developed nations like the United States of America to the very remote areas of developing nations like India. This paper aims at presenting the various facets of Distributed Generation , from its history to its present-day applications. The various Distributed Energy Resources (DERs), their costs , their interconnection and incentives taken by the government with regard to the installation of distributed generation systems have also been discussed.
INTRODUCTION
Conventionally, in most of the countries across the world, power is generated in suitable power production units known as power plants or electrical power generating stations. Depending upon the form of energy converted into electrical energy, the generating stations have been categorised as- diesel, steam, nuclear, hydroelectric and solar power plants. In this model of power generation through centralised power stations, a large amount of energy is lost is transmitting power from the generating centre to the consumers over large distances.
The concept of distributed generation has come up as an alternative approach to power generation, with the aim of minimising, or totally eliminating, the losses caused during transmission. Under this approach, power is generated at or near the load centres. It employs small-scale technologies to produce electricity close to the end users of power. The power produced using these technologies ranges from a fraction of a kilowatt to about 100 megawatts (MW), with a very little reliance on the main distribution and transmission grid. A distributed generation system can operate in a connected grid or off-grid mode. It can thus provide an alternative to or an enhancement of the conventional electrical power grid.
Distributed generation is a faster, less expensive option to the construction of large, central power plants and high-voltage transmission lines. They offer consumers the potential for lower cost, higher service reliability, high power quality, increased energy efficiency, and energy independence. . The use of renewable distributed energy generation technologies and "green power" such as wind, photovoltaic, geothermal, biomass, or hydroelectric power can also provide a significant environmental benefit. These Distributed energy resources(DERs) have been described in the succeeding chapters.
RECIPROCATING ENGINES (DIESEL OR NATURAL GAS):
A reciprocating engine, or piston engine, is a heat engine that uses one or more reciprocating pistons to convert pressure into rotating motion.. Reciprocating engines, developed more than 100 years ago, were the first among Distributed Generation technologies. Both Otto (spark ignition) and Diesel cycle (compression ignition) engines have
gained widespread acceptance in almost every sector of the economy. Smaller engines are primarily designed for transportation and can usually be converted to power generation with a little modification. Larger engines are most frequently designed for power generation. A generator is attached to the IC engine to convert the rotational motion into power. They are available from small sizes (e.g., 5 kW for residential back-up generation) to large generators (e.g., 7 MW).
Reciprocating engines for distributed can be fuelled by diesel or natural gas with varying emission outputs. Almost all engines used for power generation are four-stroke and operate in four cycles (intake, compression, combustion, and exhaust). The process begins with fuel and air being mixed. In turbocharged applications, the air is compressed before mixing with fuel. The fuel/air mixture is introduced into the combustion cylinder and ignited with a spark. For diesel units, the air and fuel are introduced separately with fuel being injected after the air is compressed.
COMBUSTION GAS TURBINES:
Conventional combustion turbine (CT) generators are a very mature technology. They typically range in size from about 500 kW up to 25 MW for Distributed Energy Resources. Units from 1-15 MW are generally referred to as industrial turbines (or sometimes as miniturbines), which differentiates them both from larger utility grade turbines and smaller microturbines. Modern single-cycle combustion turbine units typically have efficiencies in the range of 20 to 45% at full load. Efficiency is somewhat lower at less than full load. Historically, they were developed as aero derivatives, spawned from engines used for jet propulsion. Some, however, are designed specifically for stationary power generation or compression applications in the oil and gas industries. Multiple stages are typical and along with axial blading differentiate these turbines from the smaller microturbines.
DISTRIBUTED.pdf (Size: 614.55 KB / Downloads: 86)
ABSTRACT
Increased demands on the nation's electrical power systems and incidences of electricity shortages, power quality problems, rolling blackouts, and electricity price spikes have caused many utility customers to seek other sources of high-quality, reliable electricity. In such a scenario , the approach of distributed generation , which involves the production of electricity close to the end users of power , has come up as an alternative to , or an enhancement of the traditional electrical power grid. Distributed generation may be defined as the installation and operation of small modular power generating technologies that can be combined with energy management and storage systems. This system can employ a range of technologies – from renewable to non-renewable and can operate in either a connected grid or in off-grid mode. The technologies which adopt renewable resources have struck a chord with the environmental advocates as well. Thus, this approach has been gaining popularity across the world, from the modernised cities of developed nations like the United States of America to the very remote areas of developing nations like India. This paper aims at presenting the various facets of Distributed Generation , from its history to its present-day applications. The various Distributed Energy Resources (DERs), their costs , their interconnection and incentives taken by the government with regard to the installation of distributed generation systems have also been discussed.
INTRODUCTION
Conventionally, in most of the countries across the world, power is generated in suitable power production units known as power plants or electrical power generating stations. Depending upon the form of energy converted into electrical energy, the generating stations have been categorised as- diesel, steam, nuclear, hydroelectric and solar power plants. In this model of power generation through centralised power stations, a large amount of energy is lost is transmitting power from the generating centre to the consumers over large distances.
The concept of distributed generation has come up as an alternative approach to power generation, with the aim of minimising, or totally eliminating, the losses caused during transmission. Under this approach, power is generated at or near the load centres. It employs small-scale technologies to produce electricity close to the end users of power. The power produced using these technologies ranges from a fraction of a kilowatt to about 100 megawatts (MW), with a very little reliance on the main distribution and transmission grid. A distributed generation system can operate in a connected grid or off-grid mode. It can thus provide an alternative to or an enhancement of the conventional electrical power grid.
Distributed generation is a faster, less expensive option to the construction of large, central power plants and high-voltage transmission lines. They offer consumers the potential for lower cost, higher service reliability, high power quality, increased energy efficiency, and energy independence. . The use of renewable distributed energy generation technologies and "green power" such as wind, photovoltaic, geothermal, biomass, or hydroelectric power can also provide a significant environmental benefit. These Distributed energy resources(DERs) have been described in the succeeding chapters.
RECIPROCATING ENGINES (DIESEL OR NATURAL GAS):
A reciprocating engine, or piston engine, is a heat engine that uses one or more reciprocating pistons to convert pressure into rotating motion.. Reciprocating engines, developed more than 100 years ago, were the first among Distributed Generation technologies. Both Otto (spark ignition) and Diesel cycle (compression ignition) engines have
gained widespread acceptance in almost every sector of the economy. Smaller engines are primarily designed for transportation and can usually be converted to power generation with a little modification. Larger engines are most frequently designed for power generation. A generator is attached to the IC engine to convert the rotational motion into power. They are available from small sizes (e.g., 5 kW for residential back-up generation) to large generators (e.g., 7 MW).
Reciprocating engines for distributed can be fuelled by diesel or natural gas with varying emission outputs. Almost all engines used for power generation are four-stroke and operate in four cycles (intake, compression, combustion, and exhaust). The process begins with fuel and air being mixed. In turbocharged applications, the air is compressed before mixing with fuel. The fuel/air mixture is introduced into the combustion cylinder and ignited with a spark. For diesel units, the air and fuel are introduced separately with fuel being injected after the air is compressed.
COMBUSTION GAS TURBINES:
Conventional combustion turbine (CT) generators are a very mature technology. They typically range in size from about 500 kW up to 25 MW for Distributed Energy Resources. Units from 1-15 MW are generally referred to as industrial turbines (or sometimes as miniturbines), which differentiates them both from larger utility grade turbines and smaller microturbines. Modern single-cycle combustion turbine units typically have efficiencies in the range of 20 to 45% at full load. Efficiency is somewhat lower at less than full load. Historically, they were developed as aero derivatives, spawned from engines used for jet propulsion. Some, however, are designed specifically for stationary power generation or compression applications in the oil and gas industries. Multiple stages are typical and along with axial blading differentiate these turbines from the smaller microturbines.