A SEMINAR REPORT ON

DISTRIBUTED GENERATION

Submitted in partial fulfilment of the requirement for the award of the degree of

BACHELOR OF TECHNOLOGY

IN

ELECTRICAL AND ELECTRONICS ENGINEERING

BY

DARSHINALA RAJU

(10841A0210)

Under the Guidance of

Mr.MSR MURTHI Sr. Professor, EEE

AURORA’S TECHNOLOGICAL & RESEARCH INSTITUTE

Parvatapur, Uppal, Hyderabad

Affiliated to JNTUH

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CERTIFICATE

This is to certify that the seminar report entitled “DISTRIBUTED GENERATION” is the

work done by DARSHINALA RAJU (10841A0210) submitted in partial fulfilment for the

award of the degree of’ BACHELOR OF TECHNOLOGY’ in ELECTRICAL AND

ELECTRONICS ENGINEERING from AURORA’S TECHNOLOGICAL & RESEARCH

INSTITUTE affiliated to JNTU, Hyderabad.

Signature of Guide(Mr. MSR MURTHI)

Senior. ProfessorDepartment of EEE Department of EEE

Signature of the Head of the Department(Mr. JAWAHARLAL)

HOD Department of EEE

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ACKNOWLEDGEMENT

The satisfaction and euphoria that accompany the successful completion of any task would be

incomplete without the mentioning of the people whose constant guidance and encouragement

made it possible. I take pleasure in presenting before you, my seminar, which is the result of

studied blend of both research and knowledge.

I express my earnest gratitude to my guide Mr.MSR Murthy (Sr.professor,EEE), & Mr

JAWAHARLAL( HOD,EEE) for their constant support, encouragement, and guidance. I am

grateful for their cooperation and valuable suggestions.

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TABLE OF CONTENTS

Table of Contents

1.ABSTRACT……………………………………………………………………………………5

2.INTRODUCTION……………………………………………………………………………..6

Distributed generation technologies………………………………………………………..7

3.TYPES OF DISTRIBUTED ENERGY RESOURCES……………………………………….8 3.1Cogeneration…………………………………………………………………………8

3.2Solarpanel…………………………………………………………………………….9

3.3windturbine…………………………………………………………………….……10

3.4 waste-to-energy………………………………………………………………….…12

3.5 fuel cells……………………………………………………………………………………13

3.6 reciprocating diesel or natural gas turbine………………………………………………....14

3.7 micro-turbines……………………………………………………………………………...15

3.8 combustion gas turbine………………………………………………………….………….16

4. INTEGRATION WITH THE GRID………………………………………………..……..…17

5. BENEFITS OF DISTRIBUTED GENERATION…………………………………..……….17

6. CONCLUSION………………………………………………………………………..……..18

7. FUTURE SCOPE………………………………………………………………………..…...19

8. REFERENCES…………………………………………………………………………..…...20

9. REMARKS………………………………………………………………………………..….21

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1. ABSTRACT

This paper starts from the observation that there is a renewed interest in small-scale electricity

generation. . The authors start with a survey of existing small-scale generation technologies and

then move on with a discussion of the major benefits and issues of small-scale electricity

generation. Different technologies are evaluated in terms of their possible contribution to the

listed benefits and issues. Small-scale generation is also commonly called distributed generation,

embedded generation or decentralized generation.

With people attention to sustainable development and environmental pollution, distributed

generation (DG) technology with its unique environment and economy raises more and more

concern. The rapid development of DG technology results in large-capacity distributed power

connected to the grid, but DG affected by natural conditions will not deliver output power

continuously and stably. And DG usually is incorporated into the electric power system at the

distribution networks side, which will cause the system stability problems increased. In order to

fully play the role of distributed power, avoid the adverse effects of its existence, it is necessary

to study in-depth on DG and the technology of its connected to the grid. In this paper it is

researched and analyzed for problems brought by DG connected to the grid and put forward the

corresponding solution.

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2. INTRODUCTION

Distributed generation is a new trend in the generation of heat and electrical power. The concept

permits the "consumer", who is generating heat or electricity for their own needs, to send their

surplus electrical power back into the power grid or share excess heat via a distributed heating

grid.

Distributed generation is an approach that employs small-scale technologies to produce

electricity close to the end users of power. DG technologies often consist of modular (and

sometimes renewable-energy) generators, and they offer a number of potential benefits.  In many

cases, distributed generators can provide lower-cost electricity and higher power reliability and

security with fewer environmental consequences than can traditional power generators. 

In contrast to the use of a few large-scale generating stations located far from load centers--the

approach used in the traditional electric power paradigm--DG systems employ numerous, but

small plants and can provide power onsite with little reliance on the distribution and transmission

grid. DG technologies yield power in capacities that range from a fraction of a kilowatt [kW] to

about 100 megawatts [MW]. Utility-scale generation units generate power in capacities that

often reach beyond 1,000 MW.

Historically, central plants have been an integral part of the electric grid, in which large

generating facilities are specifically located either close to resources or otherwise located far

from populated load centers. These in turn supply the traditional transmission and distribution

grid that distributes bulk power to load centers and from there to consumers. These were

developed when the costs of transporting fuel and integrating generating technologies into

populated areas far exceeded the cost of developing T&D facilities and tariffs.

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DISTRIBUTED GENERATION TECHNOLOGIES:

Distributed generation takes place on two-levels: the local level and the end-point level. Local

level power generation plants often include renewable energy technologies that are site specific,

such as wind turbines, geothermal energy production, solar systems (photovoltaic and

combustion), and some hydro-thermal plants. These plants tend to be smaller and less centralized

than the traditional model plants. They also are frequently more energy and cost efficient and

more reliable. Since these local level DG producers often take into account the local context, the

usually produce less environmentally damaging or disrupting energy than the larger central

model plants.

Phosphorus fuel cells also provide an alternative route to a DG technology. These are not as

environmentally reliant as the previously mentioned technologies. These fuel cells are able to

provide electricity through a chemical process rather than a combustion process. This process

produces little particulate waste.

At the end-point level the individual energy consumer can apply many of these same

technologies with similar effects. One DG technology frequently employed by end-point users is

the modular internal combustion engine. These modular internal combustion engines can also be

used to backup RVs and homes. DG technologies can operate as isolated "islands" of electric

energy production or they can serve as small contributors to the power grid.

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3. TYPES OF DISTRIBUTED ENERGY RESOURCES

Distributed energy resource (DER) systems are small-scale power generation technologies

(typically in the range of 1 kW to 10,000 kW) used to provide an alternative to or an

enhancement of the traditional electric power system. The usual problem with distributed

generators is their high initial capital costs.

3.1 COGENERATION:

Distributed cogeneration sources use steam turbines, natural gas-fired fuel cells, Micro-turbines

or reciprocating engines to turn generators. The hot exhaust is then used for space or water

heating, or to drive an absorptive chiller for cooling such as air-conditioning. In addition to

natural gas-based schemes, distributed energy projects can also include other renewable or low

carbon fuels including bio fuels, biogas, landfill gas, sewage gas, coal bed methane, syngas and

associated petroleum gas.

In addition, molten carbonate fuel cell and solid oxide fuel cells using natural gas, such as the

ones from Fuel cell Energy and the Bloom energy server, or waste-to-energy are used as a

distributed energy resource.

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3.2 SOLAR PANEL:

A primary issue with solar power is that it is intermittent. Popular sources of power for

distributed generation are solar heat collection panels and solar panels on the roofs of buildings

or free-standing. Solar heating panels are used mostly for heating water and when the water is

heated into steam it can effectively and economically used in steam turbines to produce

electricity.

Some "thin-film" solar cells have waste-disposal issues when they are made with heavy metals

such as Cadmium telluride and Copper indium gallium selenide and must be recycled, as

opposed to silicon solar cells, which are mostly non-metallic. Unlike coal and nuclear, there are

no fuel costs, operating pollution, mining-safety or operating-safety issues. Solar power has a

low capacity factor, producing peak power at local noon each day. Average capacity factor is

typically 20%.

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3.3 WIND TURBINE:

Another source is small wind turbines. These have low maintenance, and low pollution, however

as with solar, wind energy is intermittent. Construction costs are higher than large power plants,

except in very windy areas. Wind towers and generators have substantial insurable liabilities

caused by high winds, but good operating safety. Wind also tends to complement solar. Days

without sun there tend to be windy, and vice versa. Many distributed generation sites combine

wind power and solar can be monitored online.

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3.4 WASTE-TO-ENERGY:

Municipal solid waste (MSW) and natural waste, such as sewage sludge, food waste and animal

manure will decompose and discharge methane-containing gas that can be collected as used as

fuel in gas turbines or micro turbines to produce electricity as a distributed energy resource.

Additionally, a California-based company has developed a process that transforms natural waste

materials, such as sewage sludge, into biofuel that can be combusted to power a steam turbine

that produces power. This power can be used in lieu of grid-power at the waste source (such as a

treatment plant, farm or dairy).

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3.5. FUEL CELLS:

There are many types of fuel cells currently under development in the 5-1000+ kW size range,

including phosphoric acid, proton exchange membrane, molten carbonate, solid oxide, alkaline,

and direct methanol.

Although the numerous types of fuel cells differ in their electrolytic material, they all use the

same basic principle. A fuel cell consists of two electrodes separated by an electrolyte. Hydrogen

fuel is fed into the anode of the fuel cell. Oxygen (or air) enters the fuel cell through the cathode.

With the aid of a catalyst, the hydrogen atom splits into a proton (H+) and an electron. The

proton passes through the electrolyte to the cathode and the electrons travel in an external circuit.

As the electrons flow through an external circuit connected as a load they create a DC current. At

the cathode, protons combine with hydrogen and oxygen, producing water and heat. Fuel cells

have very low levels of NOx and CO emissions because the power conversion is an

electrochemical process. The part of a fuel cell that contains the electrodes and electrolytic

material is called the "stack," and is a major contributor to the total cost of the total system. Stack

replacement is very costly but becomes necessary when efficiency degrades as stack operating

hours accumulate.

Fuel cells require hydrogen for operation. However, it is generally impractical to use hydrogen

directly as a fuel source; instead, it must be extracted from hydrogen-rich sources such as

gasoline, propane, or natural gas. Cost effective, efficient fuel reformers that can convert various

fuels to hydrogen are necessary to allow fuel cells increased flexibility and commercial

feasibility.

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3.6 RECIPROCATING DIESEL OR NATURAL GAS ENGINES:

Reciprocating engines, developed more than 100 years ago, were the first among DG technologies. They are

used on many scales, with applications ranging from fractional horsepower units that power small tools to

enormous 60 MW base load electric power plants. Smaller engines are primarily designed for transportation and

can usually be converted to power generation with little modification. Larger engines are most frequently

designed for power generation, mechanical drive, or marine propulsion.

Reciprocating engines can be fueled 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. Reciprocating engines are currently available from many manufacturers in all size ranges. They are

typically used for either continuous power or backup emergency power. Cogeneration configurations are

available with heat recovery from the gaseous exhaust.

3.7MICROTURBINES:

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Micro turbines are an emerging class of small-scale distributed power generation in the 30-400 kW size range.

The basic technology used in micro turbines is derived from aircraft auxiliary power systems, diesel engine

turbochargers, and automotive designs. A number of companies are currently field-testing demonstration units,

and several commercial units are available for purchase.

Micro turbines consist of a compressor, combustor, turbine, and generator. The compressors and turbines are

typically radial-flow designs, and resemble automotive engine turbochargers. Most designs are single-shaft and

use a high-speed permanent magnet generator producing variable voltage, variable frequency alternating current

(AC) power. Most micro turbine units are designed for continuous-duty operation and are recuperated to obtain

higher electric efficiencies.

3.8 COMBUSTION GAS TURBINES:

Combustion turbines range in size from simple cycle units starting at about 1 MW to several hundred MW when

configured as a combined cycle power plant. Units from 1-15 MW are generally referred to as industrial

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turbines (or sometimes as miniturbines), which differentiates them both from larger utility grade turbines and

smaller micro turbines.. 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 micro turbines described above.

Combustion turbines have relatively low installation costs, low emissions, and infrequent maintenance

requirements. Cogeneration DG installations are particularly advantageous when a continuous supply of steam

or hot water is desired.

4. INTEGRATION WITH THE GRID

For reasons of reliability, distributed generation resources would be interconnected to the same

transmission grid as central stations. Various technical and economic issues occur in the

integration of these resources into a grid. Technical problems arise in the areas of power quality,

voltage stability, harmonics, reliability, protection, and control. Behavior of protective devices

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on the grid must be examined for all combinations of distributed and central station generation.

A large scale deployment of distributed generation may affect grid-wide functions such as

frequency control and allocation of reserves. As a result smart grid functions, virtual power

plants and grid energy storage such as power to gas stations are added to the grid.

5. BENEFITS OF DISTRIBUTED GENERATION

As mentioned above, basic tangible benefits that may be derived out of such sort of distributed or

dispersed or decentralized generation are the following.

• Easy and quicker installation on account of prefabricated standardized components

• Lowering of cost by avoiding long distance high voltage transmission

• Environment friendly where renewable sources are used

• Running cost more or less constant over the period of time with the use of renewable sources

• Possibility of user-operator participation due to lesser complexity

• More dependability with simple construction, and consequent easy operation and maintenance

Of course the issue of intermittent supply may be a big issue, particularly when backup supply

from grid does not exist. Initial cost too may be high depending upon location in a number of

cases.

6. CONCLUSION

Distributed generation (DG) has much potential to improve distribution system performance. The

use of DG strongly contributes to a clean, reliable and cost effective energy for future. The range

of DG technologies and the variability in their size, performance, and suitable applications

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suggest that DG could provide power supply solutions in many different industrial, commercial,

and residential settings. In this way, DG is contributing to improving the security of electricity

supply. However, distribution system designs and operating practices are normally based on

radial power flow and this creates a significant challenge for the successful integration of DG

system. As the issues are new and are the key for sustainable future power supply, a lot of

research is required to study their impact and exploit them to the full extent.

7. FUTURE SCOPE

Possible future methods include risk-based planning and advanced monitoring schemes

combined with curtailment of production and consumption.

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Future generations of electric vehicles may have the ability to deliver power from the

battery in a vehicle-to-grid into the grid when needed. An electric vehicle network could

also be an important distributed generation resource.

The developed dynamic model of SOFC based DG system can be used along with micro-

turbine based DG system for combined operation to increase the efficiency of the

complete system.

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8. REFERENCES

http://en.wikipedia.org/wiki/Distributed_generation

Distributed Generation - Basic Policy, Perspective Planning, and Achievement so far in

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India- Subrata Mukhopadhyay, Senior Member, IEEE, and Bhim Singh, Senior member,

IEEE.

Integration of Distributed Generation in the Power SystemBy Math H. Bollen, Fainan

Hassan

http://shodhganga.inflibnet.ac.in/bitstream/10603/2342/16/16_chapter%206.pdf

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