Presentation on theme: "Policy and Trade Mechanism of Distributed Generation on Smart grid"— Presentation transcript:
1 Policy and Trade Mechanism of Distributed Generation on Smart grid CIRED 2011CIRED 2011Policy and Trade Mechanism of Distributed Generation on Smart gridZhu, Shouzhen Wang, XiaoyuTsinghua University
2 Contents 1 Definition of Smart Grid 2 Characteristic of Smart Grid 3 The significance for interconnected with distributed generations to power system4 Impact of Interconnecting Distributed Generation to Electric Network5 The Pricing Policies and Trading Mechanism of Distributed Generation6 Development
3 1 Defininition of Smart Grid Definition of “Smart Grid ” by CSEE Previous DefinitionA 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 self-healing and interactive. It has high automation level and supports renewable generation and flexible electricity consumption.
4 Strong and Smart GridThe 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.
5 2 Characteristics of Strong & Smart Grid InformationIntense integration and exchange of real-time informationAutomationautomatic selection of control strategyself-healing in case of damages and contingenciesInteractionInteraction among power generation, power grids, and end customers
6 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, life-cycle 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.
7 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 automationConnection of the distributed generationConnection of the storage system
8 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 energyOverall construction of practical distribution automation systemPromote application results and technical equipments of smart distribution pilot projectsConnection of the distributed generationConnection of the storage systemKey ProjectsOptimization of distribution structure and distribution automationResearch on intelligent distribution dispatching technology and its promotionPilot project for the construction of EV charging stationPilot projects for the construction of large-capacity storage
9 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.
10 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
12 3.3 DG interconnection Problem & development 2、Study the impacts of DG connection on power systemtradeTechnology rule1、Macroscopical policiessafetypolicy4、Study Economic trade mode and electric rate policies between DG and electric grid3、Established Technology and management of DG interconnection
13 3.4 Economic Technology and management of incentive policies 《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》台湾《永续能源政策纲领》2008.9返
14 4、Impact of Interconnecting Distributed Generation to Electric Network 4.1 Impact of DG on stable voltage of distribution network4.2 Impacts of DGs on power quality4.3 Impacts of DG on power system in abnormal operating situation
15 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 pollutionPeak shaving and reduce lossDynamic voltage support
16 Disadvantageous impacts on grid Add to short circuit capacity of electric gridAdd to difficulty of line voltage regulationAffect relaying protectionEffect power quality
17 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.
18 4.1 Impact of DG on stable voltage of distribution network
19 Feeder voltage and voltage change before and after DG connecting In the distribution network with DG, where rate of change is bigger is the top-priority locality of reactive-load compensation and voltage support.
20 DG locality change simulation Figure voltage contribution change with DG locality changeFigure :voltage contribution with DGs concentrated at the sole nodeVoltage distribution will have biggish differentia if DG units with the same output interconnected with different locality combination.
21 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.
22 4.3 Impacts of DG on power system in abnormal operating situation
23 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.
24 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 grid1) 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.
25 Impacts on local stability voltage response of 500kV corresponding to different DG penetrationIt 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
26 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 DG5.3 Combined Cooling Heating and Power (CCHP)5.4 The Model of Basic Price5.5 Pricing Police and Trade of CCHP5.6 Summary
27 5.1 The Pricing Policies and Trading Mechanism of Renewable-Energy-Based Distributed Generation (1) Mandatory policiesRenewable Portfolio Standard (RPS)The green certificate market—renewable energy green certificate trading system(2) Economic incentive policiesFeed-in Laws（3）Market development policiesTendering Policies
28 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 1,2010No. 14 Renewable electrical will be indemnificatory sun purchaseed by electrical company.
29 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 electricity②the deadline and duration of achieving given amount or proportion③the recognized amount or proportion of renewable energy electricity by generation, distribution, and transmission④the sorts of renewable energy and generation techniques⑤Certificates, Tracking and accounting method⑥the encouragement to the suppliers who achieve RPS and Enforcement penalties who not⑦the cost limit of generation and trade of renewable energy
30 Renewable electricity producers Quota obliged customers The green certificate market—renewable energy green certificate trading systemchargeGreen cardRenewable electricity producersAdministrator and report formsQuota obliged customersregistrationQuota monitorQuota obliged electricity customersTransaction info.dataDataGreen card transction marketFigure Green card and its procedures
31 5.2 Cost-sharing Mechanisms of Renewable DG Economic incentive policiesall sorts of incentive policiescash 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.
32 China Renewable Energy Law Applied in Jan. 1, 2006.Price management and cost-sharingNo. 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
33 5.2 Cost-sharing Mechanisms of Renewable DG Establishing Renewable FundAnalysis of the sales price of electricityThe sales price of electricity including 4 parts:purchasing cost, transmission-distribution loss, transmission-distribution tariff, and government fund.Design of cost-sharingRenewable Energy Fund =Cost-sharing levelIf shared in the wholecountry, the level of cost-sharing is only 0.95 RMB/MWh.
34 Green power marketing The principles for design Decision of tariff to voluntarily purchasingGE=RE-CE-ECfees of decontamination for coal electricityEC=0.6× (sum of quantities of equivalent of top 3 main pollution)=0.010￥/kWh, so GE=0.244￥/kWh.
35 Trading mechanism based on green power marketing Electric Power Company as the main marketing unitGreen certificate market
36 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 .
37 5.3 Combined Cooling Heating and Power (CCHP) BackgroundCCHP is a small or micro integrated energy supply system installed around the user.Compensatory expenses for the reserve capacityWhen CCHP needs spare sustainable capability from the grid while operating, it should compensate power utilities for the reserve capacity.
38 5.4 The Model of Basic Price Long term Marginal Cost methodology for pricingMarginal capacity costMarginal generation capacity costMarginal transmission & distribution capacity costyearly payback investment
39 Proportion of marginal capacity cost Basic price = (Marginal generation capacity cost + Marginal transmission & distribution capacity cost)×30%
40 5.5 Pricing Police and Trade of CCHP Determination of compensatory expensesCompensatory expenses (RMB/month) = Basic price (RMB /kW·month) × reserve capacity (kW)Marginal generation capacity cost
41 Marginal transmission & distribution capacity Basic price
42 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 interconnectionTrade mechanism of CCHP
43 Relation between the price of natural gas with cost of cost of CCHP system Figure The fluctuation of natural gas price affect CCHP generation costFigure Effect of natural gas to annual economic benefits
44 Policy Suggestions for the Development of (CCHP) Set up the interconnection rulesPromoting CCHP consultant industry, and encouraging ESCO and public utility to take part in the investment, construction and management of CCHPThe related fees of interconnectionThe 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 gird-interconnected Distributed Generation;the compensated expenses standard of spare sustainable capability refers to Basic price: RMB/KVA•month(Beijing) , RMB/KVA•month(Anhui)
45 Table Trade model of distributed CCHP of Shanghai Serial numberTrade modelremarkShanghai Pudong AirportThe 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/monthIn commission (interconnection), general no anti-injectShanghai Minghang HospitalThe 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 companiesOperate and interconnect, no anti-injectShanghai Shuya Liangzi Healthy Recreational CenterThe power supply side undertakes the cost of combining to the grid and increasing the capabilityIn commission (no interconnect)Shanghai Bao Steel (self-supply generation plant)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 unit for serving; the tax of station or region is handed in by Bao steel.In commission
46 5.6 Summary -1For renewable energy, the paper brings forward two reasonable methods of cost-sharing 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.
47 5.6 Summary -2For 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.
48 6 DevelopmentDistributed 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 systemDistributed 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.
49 MicroGridThere 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.
51 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 。CCHP laboratory in Tsinghua University