Transcript 幻灯片 1 - CIRED • International Conference on Electricity Distribution

CIRED 2011
CIRED 2011
Policy and Trade Mechanism
of Distributed Generation on
Smart grid
Zhu, Shouzhen Wang, Xiaoyu
Tsinghua University
[email protected]
Contents
1
2
3
Definition of Smart Grid
Characteristic of Smart Grid
The significance for interconnected with distributed
generations to power system
4 Impact of Interconnecting Distributed Generation to
Electric Network
5 The Pricing Policies and Trading Mechanism of
Distributed Generation
6 Development
2
1 Defininition of Smart Grid
Definition of “Smart Grid ” by CSEE
Previous Definition
A self-healing and interactive grid with high level of digitalization and
automation.
Current Version:
A reliable and efficient grid which utilizes advanced information,
communication and power technologies and equipments to systematically
realize the intelligent monitoring, analysis and decision. The grid is selfhealing and interactive. It has high automation level and supports
renewable generation and flexible electricity consumption.
3
Strong and Smart Grid
The system should be strong enough to support large capacity power transmission
and utilization, can support big wind farm for whole system smooth operation. the
system must be more robust to support reliable operation with some content
flexibility. There are still some discussions on that.
In order to satisfy the huge and fast increasing requirement of electricity demand
in the whole country, the infrastructure construction of power industry in China is
developed in a quite fast speed. Many new devices and technologies have been used
for several decade years.
After UHVAC demonstration transmission line is put into trial operation, the large
scale renewable energy generation projects, such as wind power fields about
10giga-watt level, are planned and commenced to be built. The development of the
smart grid is driven by the optimal control and management of the large power
system along with environment protection and energy efficiency improvement
which concerns power industry deeply.
The capability of self-healing is considered mainly for distribution system. The
technical guidelines for the smart substation and distribution are in the drawing
procedure, and will be issued soon. The test and demonstration systems have
already been arranged. The self-healing is one key issue for them.
4
2 Characteristics of Strong &
Smart Grid
Information
Intense integration and exchange of real-time information
Automation
automatic selection of control strategy
self-healing in case of damages and contingencies
Interaction
Interaction among power generation, power grids, and end
customers
5
2.1 Construction of Smart Grid
Generation：Integration of renewable generation, large scale of
wind/PV/storage, distributed generation(DG)
Transmission：Ultra high voltage (AC/DC), transmission planning, FACTS；
intelligent equipments, long distance transmission , etc.
Substation：Substation automation, IED, condition-based maintenance, lifecycle management, etc.
Distribution：distribution planning, advanced distribution automation，
DG/microgrid, energy storage, etc.
Operation and Control: EMS, electricity market, WAMS, advanced control
center, etc.
Information/communication：Info.& comm. infrastructure, information
modeling, cybertics, AMI, etc.
Supply/Consumption：marketing system, smart meter, demand
response, etc.
6
Smart Distribution
Distribution
To realize the functions such as the distribution
network monitor and control, voltage / reactive
power management, emergency management and
self-healing control, security alarming after the
distributed energy connection by the use of
intelligent devices, intelligent terminals, intelligent
master station system.
Distribution automation
Connection of the distributed generation
Connection of the storage system
7
Distribution
Development Focus
 Build a secure and reliable distribution network with power flow optimization,
flexibility in reconstruction and accommodation of renewable energy;
 Unified control and compatible with centralized/decentralized storage devices
and distributed energy
 Overall construction of practical distribution automation system
 Promote application results and technical equipments of smart distribution
pilot projects
 Connection of the distributed generation
 Connection of the storage system
Key Projects
 Optimization of distribution structure and distribution automation
 Research on intelligent distribution dispatching technology and its promotion
 Pilot project for the construction of EV charging station
 Pilot projects for the construction of large-capacity storage
8
3. The significance of distributed
generation interconnection
3.1 Define of distributed generation (DG)
In general, is an environmentally-friendly, energy saving
power station installed at the loads. The capacity of DG
can be from several kW to dozens MW,
and the prime motors of DG
system can be several kinds
of energy switching facilities
such as gas turbine, wind
turbine, solar energy fuel
cell ,photovoltaic cell, waste
incineration boiler, and so on.
9
3.2 As the important supplement of
large electric power system
(1) Economics
(2) Environmental protection
(3) Reliability
(4) New direction of using new energy sources
(5) Important content for power system
development manner
(6) Solution supply insufficiency in area of city
center
返
10
Beijing south
Station
Tianjin Station
11
3.3 DG interconnection
Problem & development
DG interconnection
2、Study the impacts of DG
connection on power system
trade
1、Macroscopical
policies
Technology
safety
rule
4、Study Economic
trade mode and
policy
electric rate policies
3、Established Technology
and management of DG
between DG and
electric grid
interconnection
12
3.4 Economic Technology and management of
incentive policies
返
《北京市节能减排综合性工作方案》2007
北京《加快发展循环经济建设资源节约型环境友好型城市行动计划》
2009.4
《上海市节能减排工作实施方案》2007
《上海市燃气管理条例》1999
《上海市节约能源条例》1998
《广州市新能源和可再生能源发展规划》（征求意见稿）2008.9
《深圳市推动节约能源工作实施方案》2003.6
《吉林省节约能源条例》2003.9
《河北省新能源开发利用管理条例》1997.5
《太原市清洁能源规划》2002
《安徽省节约能源条例》2006.7
《浙江省人民政府办公厅关于加快光伏等新能源推广应用与产业发展
的意见》2009.5.7
台湾《永续能源政策纲领》2008.9
13
4、Impact of Interconnecting Distributed
Generation to Electric Network
4.1 Impact of DG on stable voltage of
distribution network
4.2 Impacts of DGs on power quality
4.3 Impacts of DG on power system in
abnormal operating situation
14
Advantageous impacts on grid
Improve power supply reliability of grid,
especially the reliability of power supply
for important user;
Save cost of electric grid establish;
Improve energy use efficiency and develop
new-style energy source.
Reduce environment pollution
Peak shaving and reduce loss
Dynamic voltage support
15
Disadvantageous impacts on grid
Add to short circuit capacity of electric
grid
Add to difficulty of line voltage regulation
Affect relaying protection
Effect power quality
16
The studies of this report are
focused on
Study the impact of DG on stable voltage of
distribution network, and discuss the reasonable
locality and injecting capacity of DG units;
study the power quality of distribution network
with DG units, such as flicker, harmonics,
unbalanced voltage and DC current injection and so
on;
Study the impact of DG in the abnormal situation,
the contribution of DG to level of short circuit
capacity and protection arrangement, and local
stability of power system.
17
4.1 Impact of DG on stable
voltage of distribution network
18
Feeder voltage and voltage change
before and after DG connecting
1.05
3.0
2.5
1.03
1.02
2.0
1.01
1.00
1.5
0.99
0.98
1.0
0.97
0.5
0.96
负荷节点电压变化率(%)
负荷节点电压(p.u.)
1.04
0.95
0.0
0
2
4
6
8
10
12
14
16
18
20
负荷节点编号
节点电压变化率指标
未接入DG，表达式计算
未接入DG，潮流程序计算
接入DG，表达式计算
接入DG，潮流程序计算
In the distribution network with DG, where rate of change is
bigger is the top-priority locality of reactive-load compensation
and voltage support.
19
1.02
1.02
1.01
1.01
1.00
0.99
19
12
0.98
11
14
负荷节点电压(p.u.)
负荷节点电压(p.u.)
DG locality change simulation
25
1.00
24
0.99
0.98
23
0.97
22
0.97
13
0.96
5
10
15
20
负荷节点
Figure voltage contribution change with DG locality change
0.96
21
0.95
5
10
15
20
负荷节点
Figure :voltage contribution with DGs
concentrated at the sole node
• Voltage distribution will have biggish differentia if DG
units with the same output interconnected with different
locality combination.
20
General rule
DG plays obvious active role in voltage support;
If DG mounted position is selected at the position from
which to the end total load equals to half of DG capacity,
voltage of DG connecting point will be more stable；
In order to avoid situation that voltage of DG injecting
point is higher than voltage of sending eng, it is necessary
to restrict DG injecting capacity not beyond up limit;
Interconnecting DG with large capacity to network will
add to difficulty of substation voltage regulation. ；
In normal situation, DG should generate more active
power and less reactive power, and keep operating at high
power actor.
21
4.3 Impacts of DG on power system
in abnormal operating situation
22
Increase short circuit capacity and
impact protection setting
Impact of DG on fault current
(1) Short circuit level of fault point is so large that short circuit current of feeder 1 in
figure 3-17 exceeds capability of short circuit and broken circuit that switch gear
(cable ,short-circuiter and so on) in the feeder;
(2) Generally, there is only overcurrent protection in 10kV feeder, without directivity.
Therefore, when short circuit current of DG is too large, it will lead to protection b in
figure misoperation and breaker 2 opening, which results in unnecessary supply
interruption.
10KV开
闭站
a
DG并网增
加短路电
流容量
1
b
2
23
DG
Increase short circuit capacity and impact
protection setting
Connecting DGs with inverter interface to power grid will not add to
short circuit level of system; but connecting DGs with rotation
interface will supply short-circuit current to increase fault current at
short circuit point.
To reduce and avoid disadvantageous impact of DG parallel to grid
1) limit parallel capacity of DG;
2) augment impedance of DG isolating transformer;
3) set directional power protection at the outlet of DG.
Before connecting DG to grid, we must check generating equipment
impedance to the full, and calculate short-circuit current addition due
to DG parallel to grid, to determine interconnection capacity of DG.
And for parallel DG with large capacity, it is necessary to set
directional power protection.
24
Impacts on local stability
voltage response of 500kV corresponding to different
DG penetration
It is obvious that the case with DG and much higher system
loads shows better dynamic response than the base case. The
deviations of maximum voltage and frequency are less, and the
oscillations show very slightly better damping.
Frequency response of 500kV corresponding to
different DG penetration
25
5、The Pricing Policies and Trading
Mechanism of Distributed Generation
5.1 Renewable Energy Based Distributed
Generation (DG)
5.2 Cost-sharing Mechanisms of Renewable DG
5.3 Combined Cooling Heating and Power
(CCHP)
5.4 The Model of Basic Price
5.5 Pricing Police and Trade of CCHP
5.6 Summary
26
5.1 The Pricing Policies and Trading
Mechanism of Renewable-Energy-Based
Distributed Generation
(1) Mandatory policies
Renewable Portfolio Standard (RPS)
The green certificate market—renewable energy green
certificate trading system
(2) Economic incentive policies
Feed-in Laws
（3）Market development policies
Tendering Policies
China Renewable Energy Law
Applied in Jan. 1, 2006.
No. 14 Renewable electrical will be sun purchaseed by
electrical company.
After Emended Applied in April 1,2010
No. 14 Renewable electrical will be indemnificatory sun
purchaseed by electrical company.
28
Renewable Portfolio Standard (RPS)
RPS can effectively spur renewable development and
encourage competition among renewable energy producers.
RPS includes the following rules:
①the amount or proportion of renewable energy electricity
②the deadline and duration of achieving given amount or
proportion
③the recognized amount or proportion of renewable energy
electricity by generation, distribution, and transmission
④the sorts of renewable energy and generation techniques
⑤Certificates, Tracking and accounting method
⑥the encouragement to the suppliers who achieve RPS and
Enforcement penalties who not
⑦the cost limit of generation and trade of renewable energy
The green certificate market—renewable
energy green certificate trading system
Green
card
Green card
Renewable
electricity
producers
charge
Green card
market
charge
Transaction info.
and
Green card
Data
data
Administrator
report forms
Quota obliged
customers
Green card
transction
registratio
n
Quota monitor
Quota obliged electricity customers
Figure Green card and its procedures
5.2 Cost-sharing Mechanisms
of Renewable DG
Economic incentive policies
all sorts of incentive policies
cash subsidies, preferential pricing policies,
reductions of tax revenue, loans at low interest rates
or loans with interest allowance.
Feed-in Laws:A feed-in law is a price-based policy that
specifies the price to be paid for renewable energy.
China Renewable Energy Law
Applied in Jan. 1, 2006.
Price management and cost-sharing
No. 19 The tariff of renewable generation is decided
by the government according to type, development
level, and area of renewable generation。The tariff
should be publicized.
No. 21 The expenses for the utilities to buy
renewable generation can be included into the
generation cost and reimbursed from the retail sales
of electricity.
32
5.2 Cost-sharing Mechanisms of
Renewable DG
Establishing Renewable Fund
Analysis of the sales price of electricity
The sales price of electricity including 4 parts:
purchasing cost, transmission-distribution loss, transmissiondistribution tariff, and government fund.
Design of cost-sharing
Renewable Energy Fund =
[( PRE  PAVE )  QRE  ERE ]  QTotal
Cost-sharing level
If shared in the whole
country, the level of costsharing is only 0.95 RMB/MWh.
33
Green power marketing
The principles for design
Decision of tariff to voluntarily purchasing
GE=RE-CE-EC
fees of decontamination for coal electricity
EC=0.6× (sum of quantities of equivalent of top 3 main
pollution)=0.010￥/kWh, so GE=0.244￥/kWh.
34
Trading mechanism based on green power
marketing
Electric Power Company as the main marketing unit
Green certificate market
35
Suggestions on price policy of distributed
renewable energy generation
The total amount of renewable energy production
and consumption should be regulated.;
The nation supports to establish green electric
power system ;
The nation encourages and supports
interconnection and generation of the multiform
renewable energy ;
The State adopts a categorized electricity price
for the power purchase price of the renewable
energy electricity .
5.3 Combined Cooling Heating and
Power (CCHP)
Background
CCHP is a small or micro integrated energy supply
system installed around the user.
Compensatory expenses for the reserve capacity
When CCHP needs spare sustainable capability from
the grid while operating, it should compensate power
utilities for the reserve capacity.
37
5.4 The Model of Basic Price
Long term Marginal Cost methodology
for pricing
Marginal capacity cost
Marginal generation capacity cost
M cg
I (CR  K  Om )

(1  Rs ) R
m
At  ( K  CR  Om ) 
I
n 1
m
n
/(1  i) n
 P /(1  i)
n 1
n
n
Marginal transmission & distribution capacity cost
yearly payback investment
38
C0  I  C1  d
C35kV  I 35kV  C110kV  d110kV
Proportion of marginal capacity cost
Basic price = (Marginal generation capacity
cost + Marginal transmission & distribution
capacity cost)×30%
39
5.5 Pricing Police and Trade of
CCHP
Determination of compensatory
expenses
Compensatory expenses (RMB/month) = Basic price
(RMB /kW·month) × reserve capacity (kW)
Marginal generation capacity cost
M cg  995.2 RMB / kW  a
40
Marginal transmission & distribution capacity
Basic price
41
Collect governmental fund from CCHP
The quantum of public utility add-ons (three-gorge
fund, rural grid loan fund) is: 4 cents per kWh, for
lighting and commerce.
The related fees of interconnection
Trade mechanism of CCHP
42
Relation between the price of natural
gas with cost of cost of CCHP system
Effect of natural gas to annual
economic benefits
Annual 2500
revenue 2000
(mil.RMB) 1500
1000
500
0
1.8 1.7 1.6 1.5 1.4
Natural gas price(RMB/m3)
Figure The fluctuation of natural
gas price affect CCHP generation
cost
Figure Effect of natural gas to
annual economic benefits
Policy Suggestions for the Development of
(CCHP)
 Set up the interconnection rules
 Promoting CCHP consultant industry, and
encouraging ESCO and public utility to take part in the
investment, construction and management of CCHP
 The related fees of interconnection
 The state levies governmental fund to Distributed
Generation;
The quantum of public utility add-ons (sanxia fund, rural grid loan fund) is: 4
cents per kWh, for lighting and commerce.
 Charge compensatory expenses of the girdinterconnected Distributed Generation;
the compensated expenses standard of spare sustainable capability refers to
Basic price: 30.00 RMB/KVA•month(Beijing) , 20.00 RMB/KVA•month(Anhui)
Table Trade model of distributed
CCHP of Shanghai
Serial number
Trade model
remark
Shanghai Pudong
Airport
The power supply side undertakes the cost of combining
to the grid and increasing the capability; take
charge of standby capability cost in public grid:
27 RMB/kW/month
In commission
(interconnectio
n), general no
anti-inject
Shanghai Minghang
Hospital
The power supply side undertakes the cost of combining
to the grid and increasing the capability; the power
company charge cost for equipment of public grid
leave unused; discharge the inject cost; In many
ways financing: Shanghai power company, China
National Petroleum Corporation, Gas Corporation
of Shanghai and some design companies
Operate and
interconnect,
no anti-inject
Shanghai Shuya
Liangzi
Healthy
Recreational
Center
The power supply side undertakes the cost of combining
to the grid and increasing the capability
In commission (no
interconnect)
Shanghai Bao Steel
(self-supply
generation
The power supply side undertakes the cost of combining
to the grid and increasing the capability; Shanghai
power company charge Bao steel 0.13 RMB per
In commission
5.6 Summary -1
For renewable energy, the paper brings
forward two reasonable methods of costsharing to allocate the cost differential between
renewable energy and conventional energy.
Cost-sharing level of Renewable Energy Fund
is estimated based on the analysis of electricity
sales price and sharing principles.
Volunteering Purchasing Mechanism of green
power marketing is established.
All above methods give some suggestions of
associate measures to Renewable Law.
46
5.6 Summary -2
For CCHP, the paper brings the proposal of
compensatory expenses to the reserve capacity of
power system while interconnection.
The basic price tariff and expenses standard of
different voltage levels is calculated by using Long
Term Marginal Cost methodology.
It also brings forward the suggestions of
governmental fund and related fees.
A trading mechanism for CCHP interconnection is
given in the final.
47
6 Development
Distributed Generation is a new direction in
the development of energy resources in
future. Interconnection with the grid is a key
step in its progress.
Recognition Impact of DG to power system
Distributed Generation must have relevant
technology qualifications of interconnection.
It should accord with the capacity and
voltage level of interconnection, suffice
power quality and the conditions of
connection and disconnection.
48
MicroGrid
There are two design modes for Distributed
Generations. One is that a generator or
some supply electric power to a special user,
and they are isolated from the power grids
in electric and become a small system,call
MicroGrid.
49
50
CCHP——a newest energy integrated optimizing scheme
Distributed CCHP can effectively control or cut down the supply demands in
heating and cooling, vacate much load capacity and optimize the load
structure 。
51
CCHP laboratory in Tsinghua University
52