ENQUIRY BY SRLDC TO VERIFY THE DETAILS OF DC & AG BY NTPC AND NLC STATIONS PETITION NO:- 67/2003 (suo motto) & PETITION NO:- 90/2005 (TNEB) CERC HEARING ON 06-DEC-05

Issue of Declared Capacity (DC), & Actual Generation (AG) By Generating Stations Hon’ble Commission has issued Interim order dated 19/ directing : SRLDC to conduct an enquiry to verify the details of declared capacity (DC), and actual generation (AG) in respect of the generating stations belonging to NTPC and NLC during the period to and whether it involved gaming by the generating stations and submit a report to the commission by latest with copy to the parties to the petition filed by TNEB.

Issue of Declared Capacity (DC), & Actual Generation (AG) By Generating Stations Compliance By SRLDC  SRLDC has conducted a meeting of all the parties including TNEB on  Gist of discussions and Report of SRLDC has been sent to all the parties including the petitioner, TNEB.

Issues Details Of AG & DC Details Of AG & DC Issue Of Capacity Declared By The Generating Stations Issue Of Capacity Declared By The Generating Stations Discussions Held At SRLDC On Discussions Held At SRLDC On Submission By SRLDC Submission By SRLDC Related Issues for Consideration Of Hon’ble Commission Related Issues for Consideration Of Hon’ble Commission

during the period of 56 days ( i.e. From to ) Details of Actual Generation (AG) and Declared Capacity (DC) during the period of 56 days ( i.e. From to )

Details Of AG & DC The Range and average of the daily actual generation over DC. (During to ) STATIONRSTPSTALCHER ST2 NLCTPS2 (STAGE1) NLCTPS2 (STAGE2) NLCTPS1 (EXPANSION) Range of AG over DC Average generation over DC GENERATION LEVEL HAS NOT REMAINED CONSTANT Continue…

Details Of AG & DC (Continue..) No. of blocks when the generation level was more than 105% of DC. (out of total 5376 number of blocks) STATIONRSTPSTALCHER ST2 NLCTPS2 (STAGE1) NLCTPS2 (STAGE2) NLCTPS1 (EXPANSION ) No. Of blocks when AG > DC by 105% 3 (0.06%) 79 (1.47%) 8 (0.15%) 2 (0.04%) 161 (2.99%) AT DIFFERENT GENERATIONS THE TOTAL NUMBER OF BLOCKS WHEN AG > DC WAS IN THE RANGE OF 0.04% to 2.99% Continue…

Details Of AG & DC (Continue..) No. of days when the generation level increased beyond 101% of DC in a day. (out of total 56 number of days) STATIONRSTPSTALCHER ST2 NLCTPS2 (STAGE1) NLCTPS2 (STAGE2) NLCTPS1 (EXPANSION) No. Of days when AG > DC by 101% 37 (66.07%) 47 (83.93%) 2 (3.57%) 1 (1.79%) 16 (28.57%) At Ramagundam and Talcher stations of NTPC for 66% and 84% of the days respectively the AG was above 101 % of DC. At TPS-II (Stage-I), TPS-II(Stage-II) and TPS I (Exp.) of NLC, the number of days when the AG had exceeded the 101% DC is around 2%, 4% and 29% respectively. HOME

Issue of Capacity Declaration by the Generating Stations

ISGS stations in the Southern region had started declaring DC higher than the normative value. ISGS stations in the Southern region had started declaring DC higher than the normative value. ( normative value = Installed capacity – Normative Auxilary Consumption) ( normative value = Installed capacity – Normative Auxilary Consumption) During the above period the frequency profile of SR was below 50.0 Hz for most of the time During the above period the frequency profile of SR was below 50.0 Hz for most of the time Extra generation into the grid contributed towards economy and efficiency Extra generation into the grid contributed towards economy and efficiency Continue…

The issue in respect of actual generation by the ISGSs vis- à-vis DC has regularly been deliberated by SRLDC in the OCC meetings and generation pattern of the different generating stations with reference to DC, etc. were invariably shared with the members including the petitioner i.e. TNEB. Though the generators have responded to the suggestions of SRLDC positively, we would like to submit that at no point of time, any representative of petitioner has objected to the generation pattern by the ISGSs and rather continued to silently derive the benefits of such extra generation by sustained overdrawals from the grid. OCC meetings Issue of Capacity Declaration by the Generating Stations (Continue …)

Record Note of discussions during the meeting held at SRLDC on on the subject of Declared Capacity and Actual generation. GIST

Discussions Held At SRLDC On Difficulties Expressed By Generators Tracking of DC to match it with the AG may result into flip-flop action and instability. Tracking of DC to match it with the AG may result into flip-flop action and instability. Incorporating changes involving very low values and at very frequent intervals may not be practicable. Incorporating changes involving very low values and at very frequent intervals may not be practicable. In real time conditions to exactly assess and estimate the further overloading margins, that would be available after 1 ½ hour would be difficult. In real time conditions to exactly assess and estimate the further overloading margins, that would be available after 1 ½ hour would be difficult. Continue…

Discussions Held At SRLDC On Difficulties Expressed By Generators IEGC clause also states that when the frequency falls below 50 Hz., the generation of all ISGSs (except those on peaking duty) shall be maximized at least upto the level which can be sustained without waiting for advice from RLDC. IEGC clause also states that when the frequency falls below 50 Hz., the generation of all ISGSs (except those on peaking duty) shall be maximized at least upto the level which can be sustained without waiting for advice from RLDC. NLC TPSI (Expansion) and Talcher STPS units were recently brought under commercial operation and there were initial teething problems, which were being attended to. NLC TPSI (Expansion) and Talcher STPS units were recently brought under commercial operation and there were initial teething problems, which were being attended to. (Continue …) Continue…

Discussions Held At SRLDC On Views Expressed By States Petitioner TNEB and APTRANSCO Petitioner TNEB and APTRANSCO  not in favor of harnessing additional capacity by way of declaration of higher capacity.  do not want generators to carry out any extra generation beyond schedule. – not in line with IEGC stipulations (Clause ).  are of the view that there is possiblity for the generators to frequently revise the DC without any limitation. KSEB KSEB  Declaration of higher DC is desirable as it would enhance availability and reduce UI burden. Continue… (Continue …)

Discussions Held At SRLDC On Views Expressed By States KPTCL KPTCL  Declaration of higher DC is a wel come step as long as the machines efficiency/life is not affected. KPTCL and KSEB KPTCL and KSEB  Extra generation during low frequency is a welcome step and should be harnessed in line with IEGC stipulations. However consensus could not be arrived. (Continue …) Continue…

Submission By SRLDC

1.Harnessing of any additional generation capacity by way of declaration of higher DC beyond the normative DC is beneficial to the constituents as well as to the grid in meeting higher consumer demand and improving grid parameters, and hence must be encouraged.

2.In real time carrying out the frequent revisions of the DC to make it closer to actual generation may not be practicable.  The Hon’ble Commission is already possessed-of with the issue of frequent revisions. In the draft IEGC issued by Honorable Commission in June, 2005 a minimum cap of 50 MW has been suggested while initiating a revision, mainly to avoid frequent/small revisions. (Draft IEGC June 2005 of Clause ). Submission By SRLDC (Continue …) Modify DC Continue… DETAILS DRAFT IEGC

Submission By SRLDC (Continue …) 3.The above extra generation carried out by the stations does not come under the category of gaming …  The issue was regularly discussed and deliberaed and at no point of time the petitioner, TNEB raised any objection on the issue  Enhancement in the DC - Generators responded positively.  Generators already declaring higher DC - beyond normative Value. Continue…

Submission By SRLDC (Continue …) 4.Any extra generation to the grid particularly from Pit head generating stations must be harnessed  Will lead to economy and efficiency and benefit to the whole region.  The Hon’ble Commission during hearing on on the above issue had intended that it is desirable that such extra generation must be tapped and any commercial issues/implications related to this can be brought to the notice of commission.

Related Issues for Consideration Of Hon’ble Commission

During the meeting held with all SR constituents and SREB, on , certain related issues were raised with the request that these may be brought to the kind reference of Hon’ble Commission.  Curbing the excess generation during high frequency period.  Interpretation of the Clause 2 (ii) of Regulations 24  Harnessing of Extra Opportunistic Generation Related Issues for Consideration Of Hon’ble Commission HOME

Curbing the excess generation during high frequency period. Participating members from the States : Participating members from the States expressed that some of the thermal generating stations continue to carry out excessive generation even during high frequency period, possibly due to the fact that the Unscheduled Interchange (UI) rates existing as of now also give them a commercial signal to continue to carry out such excessive generation inspite of frequency going to a level of 50 Hz. and above. DETAILS BACK

Interpretation of the Clause 2 (ii) of Regulations 24 Clause 2 of Regulations 24 on Terms and Conditions of Tariff 2004 is as follows: Clause 2 of Regulations 24 on Terms and Conditions of Tariff 2004 is as follows: Any generation up to 105% of the declared capacity in any time block of 15 minutes and averaging up to 101% of the average declared capacity over a day shall not be construed as gaming and the generator shall be entitled to UI charges for such excess generation above the scheduled generation (SG). Any generation up to 105% of the declared capacity in any time block of 15 minutes and averaging up to 101% of the average declared capacity over a day shall not be construed as gaming and the generator shall be entitled to UI charges for such excess generation above the scheduled generation (SG). For any generation beyond the prescribed limits, the Regional Load Despatch Centre shall investigate so as to ensure that there is no gaming, and if gaming is found by the Regional Load Despatch Centre, the corresponding UI charges due to the generating station on account of such extra generation shall be reduced to zero and the amount shall be adjusted in UI account of beneficiaries in the ratio of their capacity share in the generating station. For any generation beyond the prescribed limits, the Regional Load Despatch Centre shall investigate so as to ensure that there is no gaming, and if gaming is found by the Regional Load Despatch Centre, the corresponding UI charges due to the generating station on account of such extra generation shall be reduced to zero and the amount shall be adjusted in UI account of beneficiaries in the ratio of their capacity share in the generating station. DETAILSBACK

Harnessing of Extra Opportunistic Generation The Hon’ble Commission during hearing on on the above issue had intended that it is desirable that such extra generation must be tapped and any commercial issues/implications related to this can be brought to the notice of commission. Views expressed by the different participating members are as follows: KPTCL : If any commercial mechanism is there to share the benefits arise to due to harnessing of such extra generation, then the possibility of harnessing of same can be explored. TNEB and APTRANSCO: There is no need for harnessing of such extra generation. NTPC and NLC: The ways and means of sharing the benefits due to such extra opportunistic generation can be explored. One such possibility could be that the criteria for the payment of extra generation beyond 105% in the time block can be linked to a threshold frequency - say, the payment for such extra generation may be considered only when it is carried out below a certain frequency limit (say – 49.5 Hz.) and such generation in excess of 105% should not considered for computation of excess generation above 101% in a day. BACK

Frequency Profile During to < 49.5 Hz. =11.53% <50.0 Hz.=91.12% 49.0 to 50.5=99.84% SCHEDULE & DRAWAL GRAPHS

to

Inter Regional UI Costlier Generation Of IPP has been Replaced Clause 29(1) of the Electricity Act

UI injection during the relevant period along with UI Rate STATIONRSTPS (UNIT 1-6) NLCTPSII (STAGE1) NLCTPSII (STAGE2) NLCTPS1 (EXPANSION) TALCHER (STAGE2) EXPORT TO WR/ER IMPORT FROM WR/ER UI Energy (MU) *13964 UI Rate (Paisa/Unit) ** 225** * direct export to the WR/ER constituents under UI ** the UI Rate arrived is after accruing the interregional benefit. Average UI Rate IN SR= 238 Paisa (49.74 Hz.) Average UI Rate IN ER/WR= 302 Paisa (49.60 Hz.) Frequency Profile in SR : < 49.5 Hz. = 11.53%; < 50.0 Hz. = 91.12%; 49.0 to 50.5 Hz. = 99.84% As evidently clear from the above, the extra generation carried out by the generating stations contributed in enhancing the availability and export to WR/ER regions, when they were operating at a frequency lower than SR. It can thus be seen that the extra harnessed generation was helpful in achieving overall economy and efficiency in the region.