1 aspects of smart grid operation dr. g. b. shrestha school of eee, iit guwahati email:...

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Aspects of Smart Grid Operation

Dr. G. B. Shrestha School of EEE, IIT Guwahati

email: [email protected]

13 March 2015

GB Shrestha: March 2015

QIP STC on Computational Methods for Smart Grids9th - 13th March, 2014

Indian Institute of Technology Guwahati, Assam, India

mailto:[email protected]

GB Shrestha: March 2015 2

Indian Power System Network- Grid

Two factors:

• Generation Capacity

• Transmission Network

Both capacities and interconnections growing.


Brief History of Electric Power Grid

Industry/Ownership StructuresSingle units, Isolated Systems, Interconnected Networks - Grid

RegulationsBlackouts (1965), Fuel Crisis (1973), Financial Crises

DeregulationPURPA (1978) Deregulation, and Markets, etc.

Micro-Grids – Smart Grids – Why?

Tr

Tr

Load

Tr

Line

Tie Line

1. Electric Energy cannot be stored.

Generation must exactly balance the load (plus losses)

2. Quality of Power Supply

• The voltage profile throughout the power system must be

maintained within an acceptable narrow band.

• The frequency must be maintained near the rated value - etc.

3. Level of Reliability – must be maintained

4. Environmental impact is becoming increasingly more important.

5. The role of renewable/sustainable energy is increasing.

6. The operating cost must be minimized!!!

4GB Shrestha: March 2015

Power System Operation and Planning

Tr

Tr

Load

Tr

Line

Tie Line


Load Forecast and Load Characteristics

Load Forecast

Short term, Long Term, etc. Load Curve The load duration curve Load duration curves are useful in efficient operation of power

systems.

Base Demand

- lasts all 24 hrs Peak Demand

- lasts only the

peak hour


Cost Characteristics of Power Plants

Two different types of costs are involved.

1. Operating Cost:• The fuel cost and the operation and maintenance cost basically

depends on the amount of energy produced.• For a given size of generator the cost linearly increases with the

length of time used. • The general behaviors of this component of cost for steam and

combustion turbine generators are shown below.

0 8760Time (hours/year)

$Steam Turbine

Combustion Turbine


General Cost Characteristics of Power Plants

2. Capital Cost:• The amount invested in the construction of the plant.

Both (i) return of capital, and (ii) return on the capital

will involve an annual fixed cost independent of the power produced.

• The general nature of this component of cost for steam and combustion turbine generators are shown below.


$Steam Turbine

Combustion Turbine

Combustion Turbine

Steam Turbine



• Consideration of total costs shows that:• Steam/Coal Plant costs are lower if operated for T hrs or more.• Combustion plant costs are lower if operated for less than T hrs.


$

T

The sum of the two cost components will determine the overall cost of energy produced.



• Such cost characteristics are called the screening curves.• These curves are used in the operation and planning of generation capacity. • A set of screening curves for various types of generators may be as shown

below.


Classification of Generators

Specification:• Size, voltage level, efficiency, availability, etc

Cost• Capital cost, fuel cost, etc

Type of Use• Base Load Unit• Intermediate Unit• Peaking Unit


Daily Scheduling

1. Forecast the power demand for the day.

2. Determine suitable spinning reserve margin. Run (start and/or shut down) the generators in the order of increasing cost.

3. Note that the base units will be on all the time, while peaking units will be used for during the peak hours only.

4. In practice, thefailure of generatorswill have to be taken into account.

Hours

Spinning Reserve

GenerationCapacity

Dem

and/

Cap

acit

y


Challenges Facing Electric Power Industry

US ScenarioGeneration capacity:

(2008) 1,022 GW

(2030) 1,400 GW

New Additions Required: 600 units of 1,000 MW plants

Chinese ScenarioGeneration capacity: Per Capita Consumption

(2006) 622 GW < 0.5 kW

(2020) 1,500 GW 1 kW

(2030-2050) 2,400 GW 1.5 kW

New Additions Required: 1800 units of 1,000 MW plants


Source: IEA, Key World Energy Statistics 2007** Other includes geothermal, solar, wind, combustible renewables & waste

World Electricity Generation by Fuel


Electricity Generation by Fuel Types for Selected Countries

49.6%

79.0%

68.7%

28.1%

3.0%

2.4%

4.5%

13.2%

19.1%

0.5%

8.9%

21.0%

19.3%

2.1%

2.5%

27.6%

9.0%

16.0%

15.5%

10.1%

0.0% 20.0% 40.0% 60.0% 80.0% 100.0%

US

China

India

Japan

Renewable

Nuclear

Gas

Oil

Coal

Source: International Energy Agency (IEA Statistics 2005 data, available as of June 2008)


Generation Mix of Indian Power System

• Present renewable resources contribution is about 11 %• 14 % of the capacity is owned by non-utilities as captive plants

• Total installed capacity: 201.64 GW (April 2012)


Challenges in Meeting Forecasted Demands

Where to put these two thousand 1,000 MW power plants in China and the United States?

Where would you find the water to run these coal or nuclear power plants?

How to deal with environmental effects?


Likely Scenario

Electricity supply mix move away from fossil fuels with

expanded development of wind, solar, biomass, geothermal,

nuclear and energy from the oceans

Expanded focus on energy efficiency

Greater application of IT and communication technologies

Smart electric power grid


Attributes of Smart Grids

Use of information technologies to improve electricity delivery from power plants to consumers

Consumers to interact with the grid Integrates new and improved technologies into the

operation of the grid Information-based Communicating Secure Self-healing Reliable Flexible Cost-effective Dynamically controllable

19

Diverse Energy Sources

http://powerelectronics.com/power_systems/smart-grid-success-rely-system-solutions-20091001/

Wind

Solar

Consumer

Fossil

EVs

http://powerelectronics.com/power_systems/smart-grid-success-rely-system-solutions-20091001/


Renewable Resources

Solar Energy Systems Wind Energy Systems

Mini-hydro Power Plants Bio-Energy

Geothermal, Tidal, and Wave Power Plants


Future Prospects - How does the future look?

GB Shrestha: EE 8085 - January 201122

Fastest Growing Energy Sources in the WorldGlobal % Growth in 2009 by Energy Source

31

47

3.9

-2.4-1.6

-2

1.2

-0.2

-5

0

5

10

15

20

25

30

35

40

Source: Statistical Review of World Energy 2010 (bp.com)Note: Wind, PV, Geothermal – (installed capacity MW); Gas, Oil, Hydro, Coal, Nuclear


Wind Power Highlights

Source: BP, 2008 and WWEA, 2008

Global wind capacity: 93,849 megawatts (end of 2007)

Some leading countries:

Wind turbines generate more than 1% of the global electricity.

Germany (27.8%) Spain (15.7%) USA (15.7%) India (8.5%) Denmark (4.2%)


Source: BP.com, 2008

World Wind Energy - Total Installed Capacity

MW

GB Shrestha: March 2015 25Source: WWEA, 2008

Worldwide Wind Energy by Continents

Africa 0.4%

North America 20%

Latin America 0.6%

Asia 17%

Australia Pacific 1.2%

Total Installed Capacity 2007 (Total: 93.9 GW)

Europe 61%


Share of Wind in Total Electricity Generation (2006)

Source: BP.com, 2007

US India Calif. EU Ger. Spain Den.


Cumulative Installed Wind Turbine Capacity (MW) - China

146 200 262352 406 473

571769

1,264

2,588

0

500

1000

1500

2000

2500

3000

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006

Year

Megaw

att

s (

MW

)

Cumulative installed capacity (MW) at the end of 2007： 6,050MW.Source: www.BP.com

http://www.BP.com/


1,6112,141 2,445 2,610

4,2454,674

6,361 6,750

9,181

11,635

0

2000

4000

6000

8000

10000

12000

14000

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006

Year

Megaw

att

s (

MW

)

Cumulative Installed Wind Turbine Capacity (MW)- US

Cumulative installed capacity (MW) at the end of 2007： 16,818 MW.Source: www.BP.com and www.awea.org

http://www.BP.com/

http://www.awea.org/


Offshore wind turbines - Horns Rev, Denmark

Source: BWEA © Elsam A/S

80 x 2MW = 160 MW


Solar Power Highlights

Source: EPIA, 2008 and BP, 2007

Current solar PV capacity: 9,100 megawatts (end of 2007)

Some leading countries:

- Germany (38.6%)

- Japan (38.4%)

- USA (12.9%)

- Spain (1.6%)

Above 40% growth rate continued in 2004 and 2005, more than doubling the solar PV capacity in two years.


Global Installed Solar Photovoltaics

Source: EPIA, 2008

Cumulative Capacity 1992-20059,100

6,851

5,253

3,847

2,795


Cost Characteristics of Renewable Generation

Costs:.

1. Operating Cost:• The fuel cost practically zero (solar, wind, hydro, etc.)• Other operating costs = negligible (may not be quite so for

hydro).

2. Capital Cost:• Usually extremely high

3. Desirable Economic Operating Practice:• As long as possible

4. Actual Physical Behavior:

• Highly uncertain

• Solar – only during sunshine hours,

• Wind - only during windy periods, etc.

0

100

200

300

400

0 4 8 12 16 20 0 4 8 12 16 20 0 4 8 12 16 20

TIME (HOUR)

SOL

AR

PO

WE

R (

WA

TT

)


System Characteristics and Markets for Renewable Generation

5. Markets• Interconnection Issues• Energy Price Issues• PPAs


Cost-Competitiveness of Selected Renewable Power

Technologies

Source: Renewable Energy: RD&D Priorities, OECD/IEA 2006.


Thank You!

Present System Performance - Singapore

SARFIx – System Average RMS (variation) Frequency Index37GB Shrestha: March 2015


Modern Coal Power Plant


Basic Gas Turbine

Compressor

Fuel100%

Fresh air

Combustion chamber

Turbine

Exhaustgases 67%

Generator

ACPower 33%

1150 oC

550 oC

Brayton Cycle: Working fluid is always a gas

Most common fuel is natural gas

Maximum Efficiency

550 2731 42%

1150 273

Typical efficiency is around 30 to 35%


Combined Cycle Power Plants

Efficiencies of up to 60% can be achieved, with even highervalues when the steam is used for heating


Smart Nation

42

P42

North China

South China

North East

Tibet

Taiwan

North West

Centre China

上海

East China

Xinjiang

Chuanyu

Jinshajiang Hydro

Jin,Shan,Mong Coal Base

Lo

ad cen

ters

To Centre, East

To North and

Central China

Xinjiang Coal ase

Sichuan Hydro

Tibet Hydro

To Centre,East

To Centre

The long time goal of transmitting power from the West to the East

Source: X. Zhao, China EPRI


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