ITU Kaleidoscope 2014 Living in a converged world -­‐ impossible without standards? Distributed Demand-Side Management
with Load Uncertainty
Emmanuel Manasseh
Hiroshima University, JAPAN
manasejc@ieee.org
Saint Petersburg, Russian FederaEon OUTLINES
v Introduction
v Smart Grid & Demand Side Management
v Energy Consumption Schedule
v System Model & Optimization Problem
v Simulation results
v Conclusion
Saint Petersburg, Russian Federation, 3-5 June 2014
ITU Kaleidoscope 2014 - Living in a converged world - impossible without standards?
What is Smart Grid?
A smart grid is a modernized electrical grid that uses
information and communications technology to gather and
act on information in an automated fashion to
improve the efficiency, reliability, economics, and
sustainability of the production and distribution of
electricity.
v  v  Electric grid modernization involves,
1. Improvement of infrastructure
2. Addition of the digital layer
3. Business process transformation
Saint Petersburg, Russian Federation, 3-5 June 2014
ITU Kaleidoscope 2014 - Living in a converged world - impossible without standards?
How is it different from the existing Electricity Grid ?
Saint Petersburg, Russian Federation, 3-5 June 2014
ITU Kaleidoscope 2014 - Living in a converged world - impossible without standards?
What is Demand side Management ?
v  DSM
is the modification of consumer’s demand of
electricity through various methods such as financial
incentives and consumer education
v A process by which electrical utilities in collaboration with
consumers, achieve predictable and sustainable change in
electricity demand
v Usually the goal of DSM is to encourage the
consumers to use less energy during peak hours or to
move the time of energy use to the off-peak hours
Saint Petersburg, Russian Federation, 3-5 June 2014
ITU Kaleidoscope 2014 - Living in a converged world - impossible without standards?
Energy Consumption Schedule (ECS)
v  The ECS devices are built inside the smart meters
v Smart meters are connected to communication networks and
power grid.
v  The aim is to reduce the total energy cost as well as the peakto average-ratio (PAR)
v Two approaches for energy consumption management in
buildings:
Reducing consumption and Shifting Consumption
v Deployment of storage and ECS devices for DSM
Saint Petersburg, Russian Federation, 3-5 June 2014
ITU Kaleidoscope 2014 - Living in a converged world - impossible without standards?
System Model I
v We consider N users served by one utility company.
v Each user has a smart meter with ECS, that communicates
with his/her devices and the utility company through the
advanced metering infrastructure (AMI)
v Each user n ∈ N, is considered to have non-adjustable
loads, adjustable load and a storage device.
v  Kn→ a set of adjustable load appliances: PHEVs, air
conditioner, etc.
v For each device k 2 Kn , we define energy
consumption Scheduling vector
1
T
xn,k , [xn,k
, . . . , xn,k
]
Saint Petersburg, Russian Federation, 3-5 June 2014
ITU Kaleidoscope 2014 - Living in a converged world - impossible without standards?
t
x
v  n,k
System Model II
→ one-hour energy consumption scheduled for
device k from subscriber n
v Non-adjustable load at slot t is
t
xn,0
v User n is also having a storage device
v Let pnt
0 , t = 1 , . . . , T , be the energy available in
the battery at the end of slot t , and pnmax the
capacity of the battery.
0
p
v The available energy at the beginning of the horizon is n
v  The battery can be either charged or discharged during
slot t
Saint Petersburg, Russian Federation, 3-5 June 2014
ITU Kaleidoscope 2014 - Living in a converged world - impossible without standards?
System Model III
t
v bn
→ the energy drawn from or provided to the
battery.
v bn
t < 0 → discharging & bnt > 0 → charging.
v The energy stored in the battery is given by
ptn = ptn
1
+ btn ,
t = 1, . . . , T.
t
b
v  n
is constrained by the maximum charge/
discharge
b dis < b t < b ch
n
n
n
v The battery-supply energy
is no more than the
P
t
t
consumption,
bnt + k xn,k
+ pn,0
0
v Battery has efficiency ⌘n 2 (0 , 1 ), the discharge at slot is t
limited by
t
t 1
bn
⌘ n pn
Saint Petersburg, Russian Federation, 3-5 June 2014
ITU Kaleidoscope 2014 - Living in a converged world - impossible without standards?
System Model IV
v The total hourly energy consumption for n ∈ N is
lnt
,
X
xtn,k + xtn,0 + btn .
k2Kn
v For the adjustable loads, each user selects the time
interval [↵n,k , n,k ] that the energy consumption for
device k is valid to be scheduled
v Total energy consumption for device k from user n
X
is
t
n,k
En,k =
xn,k
t=↵n,k
t
xn,k
= 0 , 8t 2
/ {↵n,k , . . . ,
n,k })
Saint Petersburg, Russian Federation, 3-5 June 2014
ITU Kaleidoscope 2014 - Living in a converged world - impossible without standards?
Motivation
How to manage energy consumption of adjustable
appliances in order to reduce PAR and minimize the cost.
Formulation of Optimization Problem
v  Devices may have some maximum power levels
min
well as the minimum power level n,k
max
n,k ,
as
v The upper-bound and lower constraints on the ECS vector
xn,k for each device
min
n,k
 xtn,k 
max
n,k ,
8t 2 {↵n,k , . . .
n,k }.
v The total load of N residential users at each hour of the
X
Lt =
lnt
day is
n2N
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ITU Kaleidoscope 2014 - Living in a converged world - impossible without standards?
Cost of Electricity
v C t (·) → the cost of electricity over a slot
t
v The cost that the utility incurs to provide electricity to
the end user
v The cost of the same load may be different at
different time of the day
v  The multi-residential load control task amounts to
minimizing the total cost of electricity
Saint Petersburg, Russian Federation, 3-5 June 2014
ITU Kaleidoscope 2014 - Living in a converged world - impossible without standards?
min
x1 ,...,xN
Optimization Problem
!!
T
X
X
X
Ct
btn +
xn,k + xtn,0
t=1
subject to btn +
X
n2N
xtn,k + xtn,0
k2K
0,
k
n,k
X
xtn,k = En,k ,
t=↵n,k
min
t
max

x

8t 2 {↵n,k , . . . , n,k },
n,k
n,k
n,k ,
xtn,k = 0, 8t 2
/ {↵n,k , . . . , n,k },
t
ch
bdis
<
b
<
b
t = 1, . . . , T,
n
n
n ,
ptn = ptn 1 + btn , t = 1, . . . , T
⌘n ptn 1 .
btn
Saint Petersburg, Russian Federation, 3-5 June 2014
ITU Kaleidoscope 2014 - Living in a converged world - impossible without standards?
Optimization Problem
v The centralized fashion can be used to solve the problem
v Central unit performs the optimization
v It requires each user to provide detailed information
about his/her energy storage capabilities as well as the
energy consumption of devices.
Private issues may discourage users to subscribe to the optimization process if
Centralized fashion is adopted
v We proposed a distributed fashion.
Saint Petersburg, Russian Federation, 3-5 June 2014
ITU Kaleidoscope 2014 - Living in a converged world - impossible without standards?
Simulation Parameters
v  N = 20, each having random adjustable and non-adjustable
devices between 10 to 20
v Non-adjustable load appliances include electric bulbs, TVs,
refrigerators etc.
v These are loads whose instantaneous power or starting time cannot
be adjusted.
v Adjustable load refers to the loads whose instantaneous power,
starting time or both can be adjusted.
v Adjustable load appliances includes PHEVs, dish washers,
washing machines etc.
v Users with and without storage devices are considered.
Saint Petersburg, Russian Federation, 3-5 June 2014
ITU Kaleidoscope 2014 - Living in a converged world - impossible without standards?
Energy Consumption (kWh)
No Energy consumption Schedule ECS
(a)
80
60
40
20
0
0
5
10
15
20
25
15
20
25
Time−slot t
(b)
Cost(Dollar)
15
10
5
0
0
5
10
Time−slot t
Users without ECS, total cost $112.62
Saint Petersburg, Russian Federation, 3-5 June 2014
ITU Kaleidoscope 2014 - Living in a converged world - impossible without standards?
Energy Consumption (kWh)
Energy consumption Schedule ECS
60
40
20
0
0
5
10
15
20
25
15
20
25
Time−slot t
Cost(Dollar)
6
4
2
0
0
5
10
Time−slot t
The ECS for users without storage devices, total cost $102.72
Saint Petersburg, Russian Federation, 3-5 June 2014
ITU Kaleidoscope 2014 - Living in a converged world - impossible without standards?
Aggregate load (kWh)
(a)
60
40
20
0
1
8
16
24
16
24
16
24
Storage strategy (kWh)
Time−slot t
(b)
20
10
0
−10
1
8
Time−slot t
(c)
Cost(Dollar)
6
4
2
0
1
8
Time−slot t
Users deploying ECS and storage devices, total cost $92.54
Saint Petersburg, Russian Federation, 3-5 June 2014
ITU Kaleidoscope 2014 - Living in a converged world - impossible without standards?
8
User with No ECS
User without Storage dev.
User with Storage dev.
Daily Cost per User (Dollar)
7
6
5
4
3
2
1
0
0
5
10
User n
15
20
Comparison of cost paid by each user with/without
storage devices
Saint Petersburg, Russian Federation, 3-5 June 2014
ITU Kaleidoscope 2014 - Living in a converged world - impossible without standards?
Conclusion
v We considered deployment of ECS devices in
smart meters for DSM v Difference in pricing mechanisms employed by
utility companies gives incentive for users to
trade the energy.
v Simulation results show significant reduction in
cost for the ECS scheme over the system without
ECS
v Energy Storage devices play an important role in
reducing the cost paid by the consumers.
Saint Petersburg, Russian Federation, 3-5 June 2014
ITU Kaleidoscope 2014 - Living in a converged world - impossible without standards?
Acknowledgement
Special thanks to Tanzania
Communication Regulatory Authority
(TCRA) for their generous
donation of the travel costs.
Saint Petersburg, Russian Federation, 3-5 June 2014
ITU Kaleidoscope 2014 - Living in a converged world - impossible without standards?