Hybrid Power System
Content
Hybrid power system With Smart
EnergyManagement System.
Authors: Nabeel Ahmad
Department of Electrical Engineering
The Superior Group of Colleges.
Lahore, Pakistan
[email protected]
Abstract— Hybrid power system is energy renewable and
one-time cost based power generating system. Its reliability
period varies more than 20 years as per regular maintenance
and location based. As per increase of World population and
energy consumption become increased, and our environmental
temperature and Air Flow also increasing with production of
CO2, With respect to these all Circumstances Best source of
Energy renewable system is Hybrid Power System, where
photovoltaic cell use for Energy generator from Heat and wind
turbine Generator from Air Flow rate. Energy distribution
system managed through Smart Grid system and load
managed through Smart Energy management system where
tube Lights (AC based) replaced with 48V DC LED Lights
and inductive load managed as per power rating or as per DC
motors. This model consist of 5KW photovoltaic penal, 5KW
Wind turbine generator, 8000A based battery bank, energy
distribution through 48V DC Bus bar connected with smart
grid and 10KVA generator, utilized through Smart Energy
management System.
on primarily on AC. It may also include significant (DC)
components and DC side can be include, storage, diesel
generators and renewable generators. Small sized systems can
be all or primarily DC systems and DC components should be
of the same type as used in the medium sized systems.[3]
II. HYBRID POWER SYSTEM
It’s a renewable energy technology that satisfies energy
demands directly and avoids the need for a long distribution
infrastructure. It is a combination of different but
complementary energy generation systems based on renewable
energies and mixed (Renewable Energy source (RES)) with a
backup of Liquefied Petroleum Gas (LPG)/diesel/gasoline
generator set) is known as a hybrid power system or hybrid
system. Its sized of varies between megawatts to kilowatts as
per requirements.[4]
Keywords— Energy management system; Hybrid Power
System; Wind Turbine; Photovoltaic; LED lighting system.
I. INTRODUCTION
Hybrid system is designed for the Electrical Power
generation and Utilized of electrical power. It is an
independent source of a large centralized electricity grid and
encircled with more than one type of power sources.[1]
Mostly these are found in remote Areas. Diesel generators
used as portable and high power to weight ratio which made it
as an ideal power source for hybrid power system. A hybrid
system includes some other power source like as wind power
solar power. It increased the use of renewable resource; size
and operation of hybrid power system components are need to
match the load and available renewable resources [3].
The Size range may Varies With respect to area and location
and grid can be of megawatts to individual household power
supplies likewise in kilowatt (kW). Larger sized systems
(more than 100 kW capacities) are normally based on
alternating current (AC) of fixed frequency. Medium-size
systems (More than 10 kW nominal capacities) are also based
Fig1: Hybrid power system [2]
Best features of each energy resource in Hybrid systems can
provide grid-quality- electricity with a power range of 1
kilowatt (kW) to several hundred kilowatts(kW). They can be
developed as new integrated designs within small electricity
distribution systems (mini-grids). [4]
III. WIND POWER SYSTEM
There is two types of grids,
The first wind Power machine is built by Charles F. Brush
in 1888. Until the 1930's the Dc powered wind machine used
but not connected to the grid. It power rated by 12kW in DC
(direct current). In 1930's, the first large scale AC turbine was
constructed in the USA and in 1970s fuel crises sparked and
research on wind power in increased. In 1980s, wind power
becomes an economically attractive option for electricity
generation. In 2001, Denmark was generating more than
2000MW of electricity from 5700 wind turbines [14]. Wind
turbine is the type of energy which converts wind Energy to
electrical energy. It’s also used for charging batteries known
as wind charger.
Wind turbines are manufactured in two dimensions of vertical
and horizontal axis types. Small wind turbines are used for
battery charging. Medium sized Wind turbines are used for
domestic power supply. Arrays of large wind turbines are
an increasingly important source of renewable energy which is
in many countries {16}. Table 1 shows the classification
system for wind turbines.
1. One way Traditional Power Grid
2. Two ways Smart Grid
One way Traditional Power Grid
Fig.2: one way Traditional Power Grid [20]
Two ways Smart Grid
IV. SMART GRID SYSTEM
What is Smart Grid?
Smart grid is type of grid which is functionally the
combination of information Technology (IT) and electric
Grid.[18]
Smart Grid = IT + Electric Grid
In other words Smart grid is the grid system that controlled
and operate the power distribution grids with the help of
computer application and Networking system[19]. Major
component of smart Grid is its Automation.
Fig.3: Two ways Smart Grid [20]
V. SMART ENERGY MANAGEMENT SYSTEM
A smart Energy Management system also be defined
as a well-designed structure with sufficient access to assets,
controls, communication, information technologies, and data
for enhancement of the occupants quality of life through
comfort, reduced costs, convenience, and increased the
connectivity [7]. This idea has been widely acknowledged for
decades but very few people have seen a smart energy home
and some still have occupied one. A commonly cited reason
for this slow growth has been the excessive cost associated
with upgrading existing building stock to include ―smart‖
technologies such as network connected appliances [7].
However, the consumers have been willing to incur significant
costs for communication technologies, like as mobile phones,
DSL internet connections and TV Cable services. Table I
presents the changes in monthly income by quintiles and
overall consumer spending on communication services,
adjusted for 2012 [5]–[9].
Survey Table 1:
This information shows that consumers are not favorable to
suggestively changing their spending habits with the
introduction of new technologies. In according to US Bureau
of Labor Statistics the average home owner spent
approximately 15 % more on entertainment including mobile
phone and DSL internet services in 2012 than 22 years ago
[7]. Data represented that consumers are willing to spend extra
on hybrid vehicles than on traditional vehicles for the reasons
of other than economic payback [10]. Motivations can lead to
same end goals. A consumer can purchase a hybrid vehicle to
decrease carbon emissions in environment to reduce
dependency on foreign oil and save money. Irrespective, to
driving a hybrid vehicle contributes to an extra sustainable
energy future via reducing oil consumption. Likewise, market
and social influence can motivate the consumers to invest in
the smart technologies. The cost and the lack of apparent value
have combined to slow the acceptance of smart technologies.
[14] However, the Real cost values of smart technologies are
different with respect to population.
The Energy Information Administration (EIA) estimates that
40% of end use electricity is consumed in residences [10].
Alongside, consumer electronics, household appliances and
construction techniques are very useful for increasingly
efficient [8]. The Smart Grid Initiative for progressive output
and the end user will be enabled with approximate real time
information from the service providers [12]. This gives an
opportunity to the good management of appliances,
information flow, and other house loads in the smart
management system.
VI. SMART HOME
A well-designed home connected for the power transfer
between the electric grid and energy consuming appliances is
called smart home. [12] A smart home have feature of
switchboard to control of electrical flow in appliances as per
requirements of end-user. [13]
VII. MODEL
This model contains 5KW photovoltaic panels whose output
voltage is 48V DC and Amperes as per power Equation [1.2]
total DC output current is rated as 104 Amps.
P=VI----------------(1.1)
I=P/V----------------(1.2)
Where P is power, I is current, and V is volts
Units:
System International (SI) units of power is Watts (W), Current
(I) is Ampere and voltage (V) is (volts).
Total output current and voltage connected to the Main Dc
Bus Bar which is connected to the Smart grid which controlled
the power.
Wind Turbine Generator (WTG) model number is FD5-5/10,
its Rated of 5KVA, output voltage is 230V DC [17]. As per
equation [1.2] its output Current is 21.7 but we required 48V
dc to connect to the Main DC bus bar. Therefore after pass the
DC to DC converter net output voltage is wind turbine
Generator is 48V DC and 100 Amp current.
Specification of Wind Turbine Generator [17]:
Output Graph of WTG [17]:
Third source in hybrid system is backup Generator. Its rating
is of 10KVA. Backup Generator is used for alternative source,
when the net power of WTG and photovoltaic output become
lower than 3kW on Main DC Bus bar Then Smart Grid
forward the command to turn on the generator to maintain the
current and voltage ratio to maintain the follow of the grid
system. Battery bank rated 8kA. I/O voltage of Battery bank is
48 Volts. Smart grid is used to maintain, control and supervise
the grid system efficiently. After Grid system main part is
Smart Energy management system. The Main feature of Smart
energy system is to distribute the Energy efficiently and
balanced.
output become zero and battery backup reduced until 3KA.
Smart Grid is connected to the Smart Energy management
system where DC load is managed and special 3KW energy
load reserve for 48V DC LED lights and 5KW for other
Inductive load.
REFERENCES
1.
Fig : battery bank
In this model we used LED lights of 48V DC and power rating
of 30W and ampere rating of 0.625mA.
If we installed same Power Rated of LED into home, Offices,
and buildings instead of Ac tube lights then we can reduced
50% Power consumptions, greater reliability period, And
duration of backup system will be doubled.
Conclusion:
This model of 8KVA DC where source of Renewable
energy are Photovoltaic cell / solar system and Wind turbine
Generator system of 5KW, 5KW whose output is 48V And
230V DC but the output of Wind Turbine generator of 230V
DC converted to 48V DC and All the output line is connected
to the Main DC bus Bar. Main DC bus Bar controlled to the
smart Grid. Smart Grid also contains 10KVA Generator for
backup. IT turn on by Smart Grid when both renewable source
Barley, C. D., "A Versatile Dispatch Scheme for
Remote Hybrid Energy Systems," NREL Wind
Division Report, July, 1994.
2. Green, H. J. and Manwell, J. F., "Hybrid2- A
Versatile Model of the Performance of Hybrid Power
Systems," Proc. AWEA 1995, 1995.
3. Manwell, J. F. et al. "Recent Progress in Battery
Models for Hybrid Wind Power Systems," Proc 1995
AWEA Annual Conference, March, 1995.
4. R. Harper, Inside the Smart Home. Springer, 2003
5. U.S. Bureau of Labor Statistics, ―Beyond the
Numbers: Pricing and Spending,‖ Oct. 2012.
6. ―Spending on Newspapers and Magazines Slides as
Spending for Internet Access Soars,‖ United States
Department of Labor Bureau of Labor Statistics,
Feb-2012. [Online]. Available:
http://www.bls.gov/cex/newspapers.htm. [Accessed:
22-feb-2015]
7. U.S. Energy Information Administration, ―Annual
Energy Review 2011,‖
Sep. 2012.
8. ―RECS Data Show Decreased Energy Consumption
Per Household,‖ United States Energy Information
Administration, feb-2015. [Online]. Available:
http://www.eia.gov/consumption/residential/reports/2
009/consumptiondown.cfm. [Accessed: 22-feb2015].
9. ―CPI Inflation Calculator,‖ United States Department
of Labor Bureau of Labor Statistics. [Online].
Available:
http://www.bls.gov/data/inflation_calculator.htm.
[Accessed: 21-Dec-2012].
10. W. LeBlanc, ―Customer Priorities and Behavior:
kWhs, iPads, and Lattes,‖ Fort Collins, Colorado, 22feb-2015.
11. W. Mert, M. Watts, and W. Tritthart, ―Smart
Domestic Appliances in Sustainable Energy Systems
- Consumer Acceptance and Restrictions,‖ in
Proceedings of the ECEEE 2009 Summer Study,
1751, vol. 1761.
12. United States Congress, ―Energy Independence and
Security Act of 2007.‖ United States Government
Printing Office, Jul-2007.
13. T. Hansen, R. Roche, S. Suryanarayanan, H. J.
Siegel, D. Zimmerle, P. Young, and A. Maciejewski,
―A Proposed Framework for Heuristic Approaches to
Resource Allocation in the Emerging Smart Grid,‖
presented at the IEEE PES International Conference
on Power Systems and Technology (POWERCON
2012), Auckland, New Zealand, 2012, pp. 1 –6
14. E. H. Lysen: Introduction to Wind Energy, basic and
advanced introduction to wind energy with emphasis
on water pumping windmills. SWD, Netherlands,
1982
15. ―Hybrid Power Generation Systems‖
www.mpoweruk.com/hybrid_power.htm. Accessed:
Feb 2015
16. http://www1.eere.energy.gov/site_administration/glo
ssary.html [Accessed: Feb 2015]
17. http://wind-energyresources.com/wer_5kw_wind_turbine.html
[Accessed: March 2015]
18. Department of Energy, ―The Smart Grid: An
Introduction‖, at
http://energy.gov/oe/downloads/smart‐ grid‐
introduction. [Accessed: March 2015]
19. C. W. Gellings, The Smart Grid: Enabling Energy
Efficiency and Demand Response,CRC Press, Aug,
2009.
20. A. Carvallo, The Advanced Smart Grid: Edge Power
Driving Sustainability, Ar-tech House, June, 2011
EnergyManagement System.
Authors: Nabeel Ahmad
Department of Electrical Engineering
The Superior Group of Colleges.
Lahore, Pakistan
[email protected]
Abstract— Hybrid power system is energy renewable and
one-time cost based power generating system. Its reliability
period varies more than 20 years as per regular maintenance
and location based. As per increase of World population and
energy consumption become increased, and our environmental
temperature and Air Flow also increasing with production of
CO2, With respect to these all Circumstances Best source of
Energy renewable system is Hybrid Power System, where
photovoltaic cell use for Energy generator from Heat and wind
turbine Generator from Air Flow rate. Energy distribution
system managed through Smart Grid system and load
managed through Smart Energy management system where
tube Lights (AC based) replaced with 48V DC LED Lights
and inductive load managed as per power rating or as per DC
motors. This model consist of 5KW photovoltaic penal, 5KW
Wind turbine generator, 8000A based battery bank, energy
distribution through 48V DC Bus bar connected with smart
grid and 10KVA generator, utilized through Smart Energy
management System.
on primarily on AC. It may also include significant (DC)
components and DC side can be include, storage, diesel
generators and renewable generators. Small sized systems can
be all or primarily DC systems and DC components should be
of the same type as used in the medium sized systems.[3]
II. HYBRID POWER SYSTEM
It’s a renewable energy technology that satisfies energy
demands directly and avoids the need for a long distribution
infrastructure. It is a combination of different but
complementary energy generation systems based on renewable
energies and mixed (Renewable Energy source (RES)) with a
backup of Liquefied Petroleum Gas (LPG)/diesel/gasoline
generator set) is known as a hybrid power system or hybrid
system. Its sized of varies between megawatts to kilowatts as
per requirements.[4]
Keywords— Energy management system; Hybrid Power
System; Wind Turbine; Photovoltaic; LED lighting system.
I. INTRODUCTION
Hybrid system is designed for the Electrical Power
generation and Utilized of electrical power. It is an
independent source of a large centralized electricity grid and
encircled with more than one type of power sources.[1]
Mostly these are found in remote Areas. Diesel generators
used as portable and high power to weight ratio which made it
as an ideal power source for hybrid power system. A hybrid
system includes some other power source like as wind power
solar power. It increased the use of renewable resource; size
and operation of hybrid power system components are need to
match the load and available renewable resources [3].
The Size range may Varies With respect to area and location
and grid can be of megawatts to individual household power
supplies likewise in kilowatt (kW). Larger sized systems
(more than 100 kW capacities) are normally based on
alternating current (AC) of fixed frequency. Medium-size
systems (More than 10 kW nominal capacities) are also based
Fig1: Hybrid power system [2]
Best features of each energy resource in Hybrid systems can
provide grid-quality- electricity with a power range of 1
kilowatt (kW) to several hundred kilowatts(kW). They can be
developed as new integrated designs within small electricity
distribution systems (mini-grids). [4]
III. WIND POWER SYSTEM
There is two types of grids,
The first wind Power machine is built by Charles F. Brush
in 1888. Until the 1930's the Dc powered wind machine used
but not connected to the grid. It power rated by 12kW in DC
(direct current). In 1930's, the first large scale AC turbine was
constructed in the USA and in 1970s fuel crises sparked and
research on wind power in increased. In 1980s, wind power
becomes an economically attractive option for electricity
generation. In 2001, Denmark was generating more than
2000MW of electricity from 5700 wind turbines [14]. Wind
turbine is the type of energy which converts wind Energy to
electrical energy. It’s also used for charging batteries known
as wind charger.
Wind turbines are manufactured in two dimensions of vertical
and horizontal axis types. Small wind turbines are used for
battery charging. Medium sized Wind turbines are used for
domestic power supply. Arrays of large wind turbines are
an increasingly important source of renewable energy which is
in many countries {16}. Table 1 shows the classification
system for wind turbines.
1. One way Traditional Power Grid
2. Two ways Smart Grid
One way Traditional Power Grid
Fig.2: one way Traditional Power Grid [20]
Two ways Smart Grid
IV. SMART GRID SYSTEM
What is Smart Grid?
Smart grid is type of grid which is functionally the
combination of information Technology (IT) and electric
Grid.[18]
Smart Grid = IT + Electric Grid
In other words Smart grid is the grid system that controlled
and operate the power distribution grids with the help of
computer application and Networking system[19]. Major
component of smart Grid is its Automation.
Fig.3: Two ways Smart Grid [20]
V. SMART ENERGY MANAGEMENT SYSTEM
A smart Energy Management system also be defined
as a well-designed structure with sufficient access to assets,
controls, communication, information technologies, and data
for enhancement of the occupants quality of life through
comfort, reduced costs, convenience, and increased the
connectivity [7]. This idea has been widely acknowledged for
decades but very few people have seen a smart energy home
and some still have occupied one. A commonly cited reason
for this slow growth has been the excessive cost associated
with upgrading existing building stock to include ―smart‖
technologies such as network connected appliances [7].
However, the consumers have been willing to incur significant
costs for communication technologies, like as mobile phones,
DSL internet connections and TV Cable services. Table I
presents the changes in monthly income by quintiles and
overall consumer spending on communication services,
adjusted for 2012 [5]–[9].
Survey Table 1:
This information shows that consumers are not favorable to
suggestively changing their spending habits with the
introduction of new technologies. In according to US Bureau
of Labor Statistics the average home owner spent
approximately 15 % more on entertainment including mobile
phone and DSL internet services in 2012 than 22 years ago
[7]. Data represented that consumers are willing to spend extra
on hybrid vehicles than on traditional vehicles for the reasons
of other than economic payback [10]. Motivations can lead to
same end goals. A consumer can purchase a hybrid vehicle to
decrease carbon emissions in environment to reduce
dependency on foreign oil and save money. Irrespective, to
driving a hybrid vehicle contributes to an extra sustainable
energy future via reducing oil consumption. Likewise, market
and social influence can motivate the consumers to invest in
the smart technologies. The cost and the lack of apparent value
have combined to slow the acceptance of smart technologies.
[14] However, the Real cost values of smart technologies are
different with respect to population.
The Energy Information Administration (EIA) estimates that
40% of end use electricity is consumed in residences [10].
Alongside, consumer electronics, household appliances and
construction techniques are very useful for increasingly
efficient [8]. The Smart Grid Initiative for progressive output
and the end user will be enabled with approximate real time
information from the service providers [12]. This gives an
opportunity to the good management of appliances,
information flow, and other house loads in the smart
management system.
VI. SMART HOME
A well-designed home connected for the power transfer
between the electric grid and energy consuming appliances is
called smart home. [12] A smart home have feature of
switchboard to control of electrical flow in appliances as per
requirements of end-user. [13]
VII. MODEL
This model contains 5KW photovoltaic panels whose output
voltage is 48V DC and Amperes as per power Equation [1.2]
total DC output current is rated as 104 Amps.
P=VI----------------(1.1)
I=P/V----------------(1.2)
Where P is power, I is current, and V is volts
Units:
System International (SI) units of power is Watts (W), Current
(I) is Ampere and voltage (V) is (volts).
Total output current and voltage connected to the Main Dc
Bus Bar which is connected to the Smart grid which controlled
the power.
Wind Turbine Generator (WTG) model number is FD5-5/10,
its Rated of 5KVA, output voltage is 230V DC [17]. As per
equation [1.2] its output Current is 21.7 but we required 48V
dc to connect to the Main DC bus bar. Therefore after pass the
DC to DC converter net output voltage is wind turbine
Generator is 48V DC and 100 Amp current.
Specification of Wind Turbine Generator [17]:
Output Graph of WTG [17]:
Third source in hybrid system is backup Generator. Its rating
is of 10KVA. Backup Generator is used for alternative source,
when the net power of WTG and photovoltaic output become
lower than 3kW on Main DC Bus bar Then Smart Grid
forward the command to turn on the generator to maintain the
current and voltage ratio to maintain the follow of the grid
system. Battery bank rated 8kA. I/O voltage of Battery bank is
48 Volts. Smart grid is used to maintain, control and supervise
the grid system efficiently. After Grid system main part is
Smart Energy management system. The Main feature of Smart
energy system is to distribute the Energy efficiently and
balanced.
output become zero and battery backup reduced until 3KA.
Smart Grid is connected to the Smart Energy management
system where DC load is managed and special 3KW energy
load reserve for 48V DC LED lights and 5KW for other
Inductive load.
REFERENCES
1.
Fig : battery bank
In this model we used LED lights of 48V DC and power rating
of 30W and ampere rating of 0.625mA.
If we installed same Power Rated of LED into home, Offices,
and buildings instead of Ac tube lights then we can reduced
50% Power consumptions, greater reliability period, And
duration of backup system will be doubled.
Conclusion:
This model of 8KVA DC where source of Renewable
energy are Photovoltaic cell / solar system and Wind turbine
Generator system of 5KW, 5KW whose output is 48V And
230V DC but the output of Wind Turbine generator of 230V
DC converted to 48V DC and All the output line is connected
to the Main DC bus Bar. Main DC bus Bar controlled to the
smart Grid. Smart Grid also contains 10KVA Generator for
backup. IT turn on by Smart Grid when both renewable source
Barley, C. D., "A Versatile Dispatch Scheme for
Remote Hybrid Energy Systems," NREL Wind
Division Report, July, 1994.
2. Green, H. J. and Manwell, J. F., "Hybrid2- A
Versatile Model of the Performance of Hybrid Power
Systems," Proc. AWEA 1995, 1995.
3. Manwell, J. F. et al. "Recent Progress in Battery
Models for Hybrid Wind Power Systems," Proc 1995
AWEA Annual Conference, March, 1995.
4. R. Harper, Inside the Smart Home. Springer, 2003
5. U.S. Bureau of Labor Statistics, ―Beyond the
Numbers: Pricing and Spending,‖ Oct. 2012.
6. ―Spending on Newspapers and Magazines Slides as
Spending for Internet Access Soars,‖ United States
Department of Labor Bureau of Labor Statistics,
Feb-2012. [Online]. Available:
http://www.bls.gov/cex/newspapers.htm. [Accessed:
22-feb-2015]
7. U.S. Energy Information Administration, ―Annual
Energy Review 2011,‖
Sep. 2012.
8. ―RECS Data Show Decreased Energy Consumption
Per Household,‖ United States Energy Information
Administration, feb-2015. [Online]. Available:
http://www.eia.gov/consumption/residential/reports/2
009/consumptiondown.cfm. [Accessed: 22-feb2015].
9. ―CPI Inflation Calculator,‖ United States Department
of Labor Bureau of Labor Statistics. [Online].
Available:
http://www.bls.gov/data/inflation_calculator.htm.
[Accessed: 21-Dec-2012].
10. W. LeBlanc, ―Customer Priorities and Behavior:
kWhs, iPads, and Lattes,‖ Fort Collins, Colorado, 22feb-2015.
11. W. Mert, M. Watts, and W. Tritthart, ―Smart
Domestic Appliances in Sustainable Energy Systems
- Consumer Acceptance and Restrictions,‖ in
Proceedings of the ECEEE 2009 Summer Study,
1751, vol. 1761.
12. United States Congress, ―Energy Independence and
Security Act of 2007.‖ United States Government
Printing Office, Jul-2007.
13. T. Hansen, R. Roche, S. Suryanarayanan, H. J.
Siegel, D. Zimmerle, P. Young, and A. Maciejewski,
―A Proposed Framework for Heuristic Approaches to
Resource Allocation in the Emerging Smart Grid,‖
presented at the IEEE PES International Conference
on Power Systems and Technology (POWERCON
2012), Auckland, New Zealand, 2012, pp. 1 –6
14. E. H. Lysen: Introduction to Wind Energy, basic and
advanced introduction to wind energy with emphasis
on water pumping windmills. SWD, Netherlands,
1982
15. ―Hybrid Power Generation Systems‖
www.mpoweruk.com/hybrid_power.htm. Accessed:
Feb 2015
16. http://www1.eere.energy.gov/site_administration/glo
ssary.html [Accessed: Feb 2015]
17. http://wind-energyresources.com/wer_5kw_wind_turbine.html
[Accessed: March 2015]
18. Department of Energy, ―The Smart Grid: An
Introduction‖, at
http://energy.gov/oe/downloads/smart‐ grid‐
introduction. [Accessed: March 2015]
19. C. W. Gellings, The Smart Grid: Enabling Energy
Efficiency and Demand Response,CRC Press, Aug,
2009.
20. A. Carvallo, The Advanced Smart Grid: Edge Power
Driving Sustainability, Ar-tech House, June, 2011
