INTRA – STATE ABT IN DELHI AS A FIRST IN THE WHOLE COUNTRY INTRA-STATE ABT HAS BEEN IMPLEMENTED FOR DELHIw.e.f. 1-4-2007.AS PER THE ORDER OF DELHI ELECTRICITY REGULATORY COMMISSIONDATED 31-3-2007
Why Intra – State ABT • Intra-state ABT is a techno-economic • tool for bringing rational tariff structure for supply of electricity from State generators to the distribution Licensees. • It is a mechanism for enforcing discipline in the Grid.
Benefits of Intra – State ABT • a) Benefits to the Power System • Brings about grid discipline by maintaining frequency in prescribed band (49.5 to 50.5 Hz). • Ensures optimum utilization of available generation capacities. • Enhances opportunities for Open access, and Trading of electricity. • Scope for encouraging competition among generators.
b) Benefits to the Generator • Encourages maximization of Generation during peak hours with incentives and discourages the same during off-peak hours with penalties linked with frequency. • Enables systematic scheduling in terms of long term, short term as well as day ahead, duly considering plant availability and maintenance. • Ensures better life of equipments due to efficient management of Demand Vs Supply. Thereby the ‘Hidden Costs’ due to damage is avoided. • The three-part Tariff under ABT provides for proper recovery of fixed and variable costs of Generator.
c) Benefits to the Distribution Licensees • Economic efficiency dictates that the least cost power should be dispatched in preference to costly power (Merit Order Dispatch). ABT provides for the same. • Licensees can plan their requirement, both for peak and off peak demands. • Enables efficient Load Management through their own Area Load Dispatch Centers.
d) Benefits to the End Users • Enables open access, captive generation and trading of electricity. • Ensures quality and reliable power supply. • Scope for reduction in cost of power due to licensees opting for merit order dispatch in their scheduling.
Constituents of Intra-State System after restructuring of DVB DELHI VIDYUT BOARD All the assets and liabilities of DVB are acquired by GNCTD All the liabilities of DVB are transferred to Holding Company, entire Equity of Holding Company is issued to GNCTD Government of National Capital Territory of Delhi Holding Co. Distribution Licensees Genco Transco NDMC MES BRPL BYPL NDPL
CONSTITUENTS OF INTRA-STATE ABT in DELHI • BSES RAJDHANI POWER CO. LTD. • BSES YAMUNA POWER CO. LTD. • NORTH DELHI POWER CO. LTD. • NEW DELHI MUNICIPAL COUNCIL. • MILITARY ENGINEERING SERVICES. • IP STATION. • RPH STATION. • GT STATION. • PRAGATI STATION. • BADARPUR THERMAL POWER STATION.
Power Allocation to Distribution Licensees POWER PURCHASE AGREEMENTS HAVE BEEN ASSIGNED TO THE DISTRIBUTION LICENSEES BY THE ORDER OF DERC DATED 31.3.2007. THE SALIENT FEATURES OF PPA ASSIGNMENT ARE AS UNDER :- • NDMC & MES have been allocated 350 MW & 50 MW respectively from the BTPS generating station as basic allocation. • Allocation from other Central Sector and State Sector has been assigned to BRPL, BYPL & NDPL in line with their consumption pattern for the period 1.7.2002 to 28.2.2007. • 15% of BTPS (after allocation to NDMC and MES) +DADRI NCTPS thermal)+ IP+RPH+PPCL+GT has been considered as un-allocated share and is placed at the disposal of the Govt of NCT of Delhi. • In case the allocation of the un-allocated power is not made by the government the same would be allocated to the distribution licensees except NDMC and MES in proportion to the basic allocation.
Power Allocation Table ON THE BASIS OF DERC ORDER DATED 31.3.2007, THE SOURCE-WISE ALLOCATION OF POWER TO THE DISTRIBUTION LICENSEES HAS BEEN COMPUTED AS UNDER FOR SCHEDULING PURPOSES :-
Steps Taken By SLDC Delhi For Implementation of Intra-State ABT The Scheduling & Dispatch procedures finalized with stake holders on 31.3.2007. All Distribution Licensees authorized SLDC to schedule available resources as per the requirement of Grid in line with the IEGC provisions section 6.5(5) which stipulates as under : “The SLDCs may also give standing instructions to the RLDC such that the RLDC itself may decide the drawal schedules for the States.” This ensures centralized scheduling for optimum utilization of available sources to Delhi as a whole. This procedure has been in existence since December 2002 i.e. the date of implementation of ABT in NR.
SCHEDULING GUIDELINES CONSTITUENTS • 1. While requisitioning power requirement ,minimum technical requirement to ensure the continuity of the generating stations and maximum availability should be taken care of by DISCOMs. The requisition from central sector gas stations should not be less than 70% of the respective availability capacity in normal conditions and 50% under emergency conditions. As far as Hydro and Nuclear stations are concerned, the entire availability would be utilized at all the times. However the storage capacity of Hydro stations is exploited by RLDC depending upon the requirement of the grid. • 2. Requisition for BTPS should not be less than 80% due to size and age of the machines. • 3. PPCL cannot go beyond 80% due to pollution stipulations. • Full requisition should be there for IP and RPH considering their age and core generation. • 5. Due to size & pollution stipulation for IPGCL’s GT, it should not be less than 70%.
PROCESS FOR SCHEDULING BY 10:00 HRS— ISGS shall advise NRLDC the station wise MW and MWH capabilities. BY 10:00 HRS— BTPS,GENCO and PPCL shall declare the availability in 15 minutes time block in terms of MW and MWH. BY 11:00 HRS— Entitlement of the state shall be posted by NRLDC in their website www.nrldc.org for central sector. BY 11:00 HRS— SLDC shall post the GENCO,PPCL and BTPS availability in its website www.delhisldc.org BY 13:00 HRS— NDPL,BRPL,BYPL,NDMC and MES shall intimate the SLDC, source-wise requirement of power for succeeding day in terms in MW and MWH in 15 minutes time block. BY 15:00 HRS— SLDC shall assess the requirement of power from all sources and intimate the same to NRLDC. BY 17:00 HRS— NRLDC shall convey the net drawal schedule for Delhi and posted in the website. BY 18:00 HRS— SLDC shall post the provisional Drawal Schedule and Generation Schedule of Generating stations within Delhi based on the provisional Drawal schedule of Delhi as a whole posted on the NRLDC website. BY 19:00 HRS— GENCOs/Licensees shall alter the schedule of generation /requirement and intimate the same to SLDC for forwarding the same to NRLDC for incorporation in final drawal schedule of Delhi. BY 22:00 HRS— SLDC shall inform the modification if any,for incorporating in the final drawal schedule to NRLDC. BY 23:00 HRS— NRLDC shall issue the final drawal schedule of Delhi state along with other states and posted in their website. BY 23:30 HRS— SLDC shall compute the drawal schedule of DISCOMs and generation schedule of generating stations within Delhi based upon the availability from central sector stations bilateral agreements entered into by various distribution licensees for the next day. Intra-day scheduling as per IEGC provisions is also permitted.
ABT BILLING METHODOLOGY • ABT is, basically, a three part tariff system consisting of the following components :- • Fixed charges – on monthly basis subject to adjustment on yearly basis. • Variable charges - on monthly basis. • Unscheduled inter-change (UI) charges. – on weekly basis.
FIXED CHARGES • The Fixed Charges are to be paid to the Generating Source on the basis of allocation irrespective of the drawal provided the generating stations attain respective availability factor prescribed by the appropriate Regulatory Commissions. For Central sector Thermal and Gas Stations the availability factor is fixed at 80% whereas for Hydro Stations the availability factor (capacity index) is 90% except few stations i.e. Tanda & Talchar Thermal stations. The nuclear stations are not covered under the ABT. VARIABLE CHARGES • The Variable Charges are to be paid to the Generating sources on the basis of scheduled allocation fixed by the Regional Load Despatch Centre keeping in mind the technical limits for regulation of generation. The limit is 70% of the maximum available capacity for thermal stations whereas that of Gas stations it is 60% in normal conditions and 50% in extreme emergency condition as fixed by RPC Forum. • As far as Hydro and Nuclear stations are concerned, the entire availability would be utilized at all the times. However the storage capacity of Hydro stations is exploited by RLDC depending upon the requirement of the grid.
UNSCHEDULED INTER-CHANGE (UI) CHARGES • The UI fora Generating Stationshall be equal to itsactual generationminus itsscheduled generation. UI forStatesshall be equal to itstotal actual drawalminus itstotal scheduled drawal. • UI shall be worked out for each 15 minutes time block. Charges for all UI transactions are based on average frequency of the time block. • The UI Tariff structure as on 31.3.2007 is as under. Average Frequency of time-block UI Rate (P/kWh) ---------------------------------------- ----------------------------------- 50.5 Hz and above 0.00 Below 50.50 Hz and upto 50.48 Hz 6.00 Below 49.04 Hz and upto 49.02 Hz 561.00 Below 49.02 Hz 570.00 Between 50.50 Hz and 49.82 Hz Linear in 0.02 Hz steps @ 6 P/kWh for each step Below 49.82 Hz Linear in 0.02 Hz steps @ 9P/kWh for each step
AS PER THE INTRA-STATE ABT ORDER OF DERC THE INTRA-STATE UI RATE WOULD BE THE RATE DECIDED BY CERC AS ON 31.3.2007. THE RATES OF UI FOR THE FREQUENCY BAND 49.0 Hz TO 50.5 Hz ARE AS UNDER
PROPOSED NEW UI RATES • CERC vide Press Release dated 7-4-2007 has proposed the New UI Vector for enforcing strict Grid discipline as given below : Average Frequency of time-block UI Rate (P/kWh) ---------------------------------------- ----------------------------------- 50.5 Hz and above 0.00 Below 50.50 Hz and upto 50.48 Hz 6.00 Below 49.52 Hz and upto 49.50 Hz 345.00 Below 49.02 Hz 745.00 Between 50.50 Hz and 49.82 Hz Linear in 0.02 Hz steps @ 6 P/kWh for each step Between 49.80 Hz and 49.52 Hz Linear in 0.02 Hz steps @ 9P/kWh for each step Between 49.50 Hz and 49.02 Hz Linear in 0.02 Hz steps @ 16P/kWh for each step COMMENTS ARE INVITED BY CERC BY 23rd APRIL 2007 ON THE ABOVE PROPOSAL FOR REVISION OF UI VECTOR.
IF THE PROPOSAL OF CERC IS IMPLEMENTED THE RATES FOR UI FOR THE FREQUENCY BAND BETWEEN 49.0 Hz & 50.5 Hz WOULD BE AS UNDER
Intra – State UI Pool Account SLDC has been mandated by the DERC order dated 31.3.2007, Para No. 18(3) to maintain the Intra-State UI Account which states as under : “SLDC Shall act as the Nodal Agency for collection and Distribution of UI charges as far as intra-state ABT is concerned. As regards regional ABT, a settlement mechanism shall immediately be worked out together by the STU, SLDC and Discoms (who are represented in the RPC) in consultation with NRLDC”.
UI SETTLEMENT MECHANISM IN INTRA-STATE ABT At Inter – state level the Unscheduled interchanges of central sector and Inter regional sources are determined with reference to their schedule at the point of injection but those of SEBs with reference to their ex-periphery schedule. Datum for working out UI not being same for all entities, this results in UI MISMATCH which is equalised by averaging the two ON DAILY BASIS. The above adjustment is required to equalize payable UI amount to receivable UI amount so that UI pool account is maintained as a Zero balance account.
METHODOLOGY FOR ZERO BALANCING THE UI POOL ACCOUNT AT INTER-STATE LEVEL • UI AMOUNT IS DRAWN FOR ALL THE UI POOL MEMBERS ON ACTUAL BASIS. • FROM THE UI ACCOUNT AMOUNT RECEIVABLE MEMBERS AND AMOUNT PAYABLE MEMBERS TO THE POOL IS SEPERATELY DRAWN OUT. • AMOUNT PAYABLE AND RECEIVABLE WILL NOT MATCH BECAUSE FOR GENERATORS THE UI IS DRAWN OUT BASED ON INJECTION & SCHEDULE AT GENERATOR PERIPHERY WHEREAS FOR STATES THE SAME IS BASED ON DRAWAL & SCHEDULE AT STATE PERIPHERY. • AS PER THE CERC STIPULATION THE UI POOL ACCOUNT SHOULD BE A ZERO BALANCE ACCOUNT. • AT RPC LEVEL THE UI MISMATCH i.e. THE DIFFERENCE BETWEEN UI PAYABLE & RECEIVABLE IS EQUALIZED BY AVERAGING THE TWO ON DAILY BASIS. HOWEVER THE UI OVER HVDC AND OTHER INTER-REGIONAL LINKS IS RETAINED WITHOUT ANY ADJUSTMENT. • THE UI MIS-MATCH IS CALCULATED ON DAILY BASIS AND APPORTIONED TO ALL UI POOL MEMBERS IN THE RATIO 50:50 TO THE PAYING AND RECEIVING MEMBERS IN THE RATIO OF THE ORIGINAL UI AMOUNT DRAWN OUT. • 7. A CASE STUDY BASED ON THE ABOVE METHODOLOGY FOR 19-3-2007 UI ACCOUNT ISSUED BY NRPC IS SHOWN IN THE NEXT SLIDE.
SAMPLE CASE FOR 19TH MARCH 2007 ACTUAL UI AMOUNT FOR PAYEE AND RECEIVING CONSTITUENTS
METHODOLOGY FOR ZERO BALANCING THE UI POOL ACCOUNT AT INTER-STATE LEVEL • MIS-MATCH BETWEEN THE PAYABLE AND RECEIVABLE AMOUNT FROM THE UI ACCOUNT IS (903.0818-820.2534)= 82.8285 LACS RUPEES. • THIS DIFFERENCE IS DIVIDED EQUALLY BETWEEN THE TWO i.e. PAYING & RECEIVING ENTITIES IN THE RATIO 50:50 AMOUNTING TO 41.41423 LACS RUPEES EACH. • SINCE NO INTER-REGIONAL LINK IS AMONGST THE RECEIVING UTILITES 41.41423 LACS IS DIVIDED AMONGST ALL THE RECEIVING UTILITIES IN PROPORTION TO THEIR UNADJUSTED UI AMOUNT. • AMONGST THE PAYING UTLITIES EXCLUDING THE INTER- REGIONAL LINKS THE AMOUNT OF 41.41423 LACS IS CREDITED TO ALL IN PROPORTION TO THEIR UNADJUSTED UI AMOUNT. • THE ADJUSTED ACCOUNTS ARE DISPLAYED IN THE NEXT SLIDE.
In Intra – State ABT also the UI account should be a Zero Balance Account which indicates UI payable/receivable to/from the Regional UI pool account should be equal to the UI receivable/payable in the Intra-State UI pool Account.The following mechanism is proposed :1. STU/SLDC shall draw-out the Intra-state UI account in same principle as that of Inter-state UI account.2. As mentioned in case of inter-state levelthe Unscheduled interchanges of Generating stations within Delhi are to be determined with reference to their schedule at the point of injection but for Distribution Licensees with reference to their ex-periphery ( at the licensees periphery) schedule.3. The amount payable / receivable to the Regional pool account would then be equated on the basis of Intra-state ABT amount. METHODOLOGY FOR ZERO BALANCING THE UI POOL ACCOUNT AT INTRA-STATE LEVEL
SAMPLE CASE FOR INTRA-STATE ABT SETTLEMENT ACTUAL UI AMOUNT FOR PAYEE AND RECEIVING CONSTITUENTS
METHODOLOGY FOR ZERO BALANCING THE UI POOL ACCOUNT AT INTER-STATE LEVEL • MIS-MATCH BETWEEN THE PAYABLE AND RECEIVABLE AMOUNT FROM THE UI ACCOUNT IS (536.268-505.000)= 31.268 LACS RUPEES. • THIS DIFFERENCE IS DIVIDED EQUALLY BETWEEN THE TWO i.e. PAYING & RECEIVING ENTITIES IN THE RATIO 50:50 AMOUNTING TO 15.634 LACS RUPEES EACH. • AMONGST THE RECEIVING UTILITES 15.634 LACS IS DIVIDED AMONGST ALL THE RECEIVING UTILITIES IN PROPORTION TO THEIR UNADJUSTED UI AMOUNT. • AMONGST THE PAYING UTLITIES EXCLUDING THE INTER- STATE ACCOUNT THE AMOUNT OF 15.634 LACS IS CREDITED TO ALL IN PROPORTION TO THEIR UNADJUSTED UI AMOUNT. • THE ADJUSTED ACCOUNTS ARE DISPLAYED IN THE NEXT SLIDE.
ACCOUNTING METHODOLOGY FOR MONTHLY ENERGY ACCOUNTS • FOR GENERATING STATIONS WITHIN DELHI • SLDC SHALL COMPUTE • A) STATIONWISE AVAILABILITY BASED ON THE DECLARED CAPACITY BY GENERATING STATIONS ON REAL TIME BASIS AS PER THE PROVISIONS OF IEGC. (IEGC STIPULATES • TO DISCOURAGE FRIVOLOUS REVISIONS, RLDC (IN DELHI’S CASE, SLDC) MAY, AT ITS SOLE DISCRETION, REFUSE TO ACCEPT SCHEDULE / CAPABILITY CHANGES OF LESS THAN TWO (2) PERCENT OF THE PREVIOUS SCHEDULE / CAPABILITY). • THESE WOULD BE COMPILED ON MONTHLY AND CUMMULATIVE FINANCIAL YEAR BASIS IN PERCENTAGE.
THE SOURCEWISE ALLOCATION WOULD ALSO BE DRAWN OUT BY SLDC BASED ON DERC ORDER ON TIME TO TIME ON MONTHLY AND CUMMULATIVE FINANCIAL YEAR BASIS IN PERCENTAGE. • SCHEDULED ENERGY FOR THE MONTH DRAWN OUT FROM DAILY IMPLEMENTED SCHEDULES PREPARED ON 15 MINUTES TIME BLOCKS. • D) INCENTIVE ENERGY ON MONTHLY BASIS AND CUMMULATIVE FINANCIAL YEAR BASIS PAYABLE BY THE DISTRIBUTION LICENSEES SHALL BE COMPUTED FOR THE ENERGY SCHEDULED FROM THE STATIONS BEYOND THE TARGET PLF FIXED FOR INCENTIVE PURPOSE FIXED BY THE APPROPRIATE COMMISSION.
2 FOR CENTRAL SECTOR • AFTER ISSUANCE OF NRPC ACCOUNTS IN RESPECT OF ISGS AND OTHER SHARED GENERATING STATIONS, SLDC SHALL COMPUTE FOLLOWING : • SOURCE WISE ALLOCATION OF THE SOURCES ON MONTHLY AND CUMULATIVE FINANCIAL YEAR BASIS IN PERCENTAGE AS SHOWN BELOW B) SOURCEWISE SCHEDULED ENERGY TO EACH DISTRIBUTION LICENSEES BASED ON THE DAILY IMPLEMENTED SCHEDULES. C) SOURCEWISE INCENTIVE ENERGY FOR THERMAL AND GAS STATIONS ON MONTHLY BASIS AND CUMMULATIVE FINANCIAL YEAR BASIS. CENTRAL SECTOR GENERATING STATIONS AND GENERATING STATIONS WITHIN DELHI SHALL RAISE BILLS ON MONTHLY BASIS BASED ON THESE ACCOUNTS ISSUED BY SLDC.
FOR TRANSMISSION CHARGES BILL, NRPC ISSUES THE WEIGHTED AVERAGE PERCENTAGE SHARE OF CENTRAL SECTOR GENERATING CAPACITY BASED ON WHICH TRANSMISSION CHARGES ARE PAYABLE TO PGCIL. THESE CHARGES WOULD FURTHER BE BIFURCATED AS PER SLDC COMPUTATION OF CENTRAL SECTOR ALLOCATION TO DISTRIBUTION LICENSEES IN DELHI. AT PRESENT, NO CENTRAL SECTOR TRANSMISSION CHARGES ARE APPLICABLE TO NDMC AND MES AS BOTH ARE NOT ALLOCATED ANY POWER FROM CENTRAL SECTOR STATIONS AS PER THE DERC ORDER. 3 CENTRAL SECTOR TRANSMISSION CHARGES
THE TRANSMISSION CHARGES APPORTIONMENT OF DISTRIBUTION LICENSEES WOULD BE AS UNDER :
FOR STATE SECTOR TRANSMISSION CHARGES, BILLS SHALL BE ISSUED BY STU BASED ON THE ALLOCATION OF STATE SECTOR GENERATING CAPACITY TO THE DISTRIBUTION LICENSEES BASED ON THE CHARGES FIXED BY DERC. 4 STATE SECTOR TRANSMISSION CHARGES
SCHEDULING EXPERIENCE In scheduling & dispatch of power there no major hurdle except the fact that there is a mismatch between requirement – availability of NDMC and MES due to entire requirement has been booked to single source i.e. BTPS. When all machines of BTPS are on bars these utilities are left with surplus power whereas if machines are down there is a shortage and over-drawal by both the utilities.
CASE STUDY FOR NDMC The following table indicates that the scheduling done by SLDC in case of NDMC and MES is most economic as mandated by the law (EA 2003 Section 32.2.(e)) which indicates “The State Load Despatch Centre shall be responsible for carrying out real time operations for grid control and despatch of electricity within the State through secure and economic operation of the State grid in accordance with the Grid Standards and the State Grid Code.”
CASE STUDYFOR MES Due to single source allocation to MES the vital utility is facing shortages due to outage of units at BTPS which is evident from the scheduling profile for 01-04-2007 as indicated hereunder : This scenario has also happened in case of NDMC when Unit No. 5 & 1 at BTPS were out due to the similar constraints.
Disposal of Surplus Power and Availing additional requirement to meet the peak demand. • SLDCs role as per IEGC clause 4 of Annexure 1 is only as a facilitator “not a trader/broker” for identifying buyer/seller for arranging scheduled inter-change within the region or across the regional boundary. • For arriving at the Drawal Schedule of Distribution Licensees they are required to indicate the quantum of power from their share to be booked for sale. They are not able to match their individual schedule with the total requirement. The example is as shown in the next slide.
Disposal of Surplus Power SLDC faced difficulties in scheduling purposes for power transfer of Delhi to UPPCL and Delhi to TPTCL during off-peak hours. In both the deals BRPL was the co-ordinator and has to give the agreed aggregate requirement of the buyers i.e. to the tune of 400 – 550 MW in case of UPPCL and upto 200 MW in case of TPC. Finally SLDC has to apply the own logic to draw out the drawal schedules of the states as was done in case of UPPCL deal effective from 5-4-07. The same percentage share has been applied to TPC deal also.
Availing the additional Power to meet the peak Demand On behalf of Discoms DTL has committed 750 MW off-take from MP during July to October’07 the corridor booking is required to be done by 19th April’07 for July transaction and 19th May’07 for August transaction, etc. SLDC requested all Distribution Licensees to book the corridor as per the individual requirement. It was also advised in case no agreement for individual agreement is arrived the ratio of CPSU allocation made to Distribution Licensees be applied for booking the corridor. The individual quantum as per CPSU allocation are as under : Note : NDMC & MES demand is likely to be met from the allocation of BTPS i.e. 49.65% and 7.09 % capacity allocation from BTPS respectively. These co-ordination activities should be done by DPPG instead of SLDC.