I-DEV0405: Use of redundant energy measurements instead of primary measurements for estimating baseline emissions

As stated in the PDD (dated on June 27th, 2008, version 2.1), the project boundary includes two vertical Francis turbines, the respective generators and the 220 KV transmission lines, among other equipment. These transmission lines connect the Power Plant (Generator 1 and 2) with Quilleco substation, where the project connects to the Central Interconnected System (SIC).
At Quilleco substation there are two primary energy meters, presented as M1 and M2. Electricity generation supplied to the grid shall be measured at Quilleco substation owned and operated by Colbún S.A., where the project connects to the grid (primary measurement).
At Quilleco Power Plant (the project site) there are also two energy meters located at the generator units, which are defined as redundant energy meters and are presented in the figure as M3 and M4. These meters are used for cross-checking tasks (secondary measurement) for CDM purposes.
Also, the Project requires electricity for auxiliary services (own consumptions of the power plant), which is fed through a separate direct power line. This electricity is measured by a dedicated electricity meter (M5), so what is read by M1 to M4 exclude the auxiliary service consumptions.
A simplified diagram (Quilleco Connection Diagram) illustrates the connection lines for Quilleco Hydroelectric Power Plant to the grid and the specific line for auxiliary services.
Meters M1 to M5 have the maximum error of 0.2%. Aenor verified on site that all indicated meters were properly installed. The initial secondary energy meters (M3 and M4) were changed for other new ones in October 2010 and the auxiliary services consumption meter (M5) was also changed in August 2010, to get the measurements by remote interface. Calibration certificates were submitted to Aenor, who verified that all meters were calibrated in accordance with the Monitoring Plan of the registered PDD.
As per the monitoring plan of the registered PDD, verification procedures shall be applied based on redundant energy meters. This cross-checking consists in comparing the measurements of the primary energy meters M1 & M2 with the measurements of the secondary energy meters M3 & M4. This procedure takes into account small losses involved in this system due to the operation of the transformer and a short transmission line (less than 0.5 km) between meters M1 & M2 and meters M3 & M4.
The current request for deviation refers to the parameter “Generationh”, related to Energy Generation of the Quilleco Hydroelectric Power Plant for each hour h.

The project deviated from the Monitoring Plan due to the two following reasons:
i) There was a recording failure of the primary meters M1 & M2 at the Quilleco substation from July 9th 2008 (starting date of the first crediting period) to August 14th 2010, including the whole first verification period. The recording failure induced the lack of registered measured values from the primary meters for the indicated period. July 8th 2009, and up.
This issue was identified and corrected by the project participant by correcting the internal operational and monitoring procedure. The readings of the primary meters have being continuously recorded since August 15th 2010.
ii) The meter for measurement of auxiliary services consumption was not properly verified for accuracy, according to local standards for electricity transactions in CDEC-SIC.
This issue was corrected by the project participant on August 13th 2010, when due a new internal measurement protocol the meter was replaced by a properly calibrated new one.
As consequence of the above deviations, the project participant (PP) proposes:
i) In the absence of registered data from the primary meters, to use the measurements of the redundant (secondary) meters M3 & M4 located at Quilleco Power Plant minus conservatively estimated losses between secondary meters (M3&M4) and primary meters (M1&M2).
ii) To apply the maximum uncertainty established by the manufacturer for auxiliary services meter (M5), class 0.2, for obtaining the measurements corrected as the most conservative data.
In order to ensure conservativeness of the suggested deviation approach:
i) The result of the deviation approach (M3+M4 minus conservatively estimated losses) is compared with the initial approach described in the PDD (M1+M2).
M3+M4-losses = M1+M2
The losses are estimated using the most conservative of the two following approaches:
Method 1: Calculation based on actual measurements for 4 and half months period;
Method 2: Calculation based on the analytical engineering study.
Please note that all meters readings (M1 to M4) already excludes the consumption by auxiliary services (own consumption of the power plant), which are feed through a separate direct power line and hence not affected by the first part of the present deviation.
Method 1: Considering that the meters located at Quilleco substation began to record on August 15th 2010, the losses between the primary and secondary metering points were calculated for a period starting on August 15th 2010 and finishing on December 31th 2010 (4 and half months). Records of the electricity generation at both primary and secondary meters were read each 15 minutes and aggregated monthly.
The total electricity generation supplied to the grid, measured with primary meters M1 & M2, during this period is 138,315,228 kWh, while the gross energy generated at Quilleco Hydroelectric Power Plant measured with the redundant meters is 139,028,755 kWh. The obtained resulting losses are 713,527 kWh for the whole period.
M1+M2 = 138,315,228 kWh; Losses = 713,527 kWh
M3+M4 = 139,028,755 kWh
139,028,755 kWh - 713,527 kWh =138,315,228 kWh

Method 2: The electrical losses between the primary and secondary metering points, which included the losses in the transformers and the transmission lines, were also assessed by an electrical study performed by the Engineer and Projects Management of Colbun. Two scenarios were analyzed and the results were validated by Aenor:
Scenario A: An estimated load of 75% of the transformer capacity;
Scenario B: The maximum load of 100% of the transformer capacity.
For conservativeness reasons, the PP is considering scenario B (PTT = 196.22 kW) which results in losses more than 50% higher than in the scenario A (PTT = 121.75 kW). Further, given that the transformers have an idle capacity (turbines maximum capacity (38000KVA) is lower than the transformers capacity (41,000 KVA)), this scenario is the most conservative since it always over-estimates the losses (both in the transformer and the transmission line).
The outcomes of the approaches used are compared for the period from August 15th 2010 to December 31th 2010 for which the actual measurement data of M1 and M2 is available. Based on this comparison, the most conservative approach is selected (see Monthly analysis).
From the two methods used, the Method 2 Scenario (B) provides the most conservative electricity generation, with losses of 1,309,180 kWh, which corresponds to an analytical value of 196.22 kW. This value is hourly discounted from the gross electricity generation during the power plant operational periods for the whole deviation period.
ii) For the same period considered above, measurements of auxiliary services meter M5 are increased a 0.2% which is the maximum uncertainty established by the manufacturer.
M5 = 1,375,952 kWh
0.2% M5 = 2,751 kWh
M5+0.2% = 1,378,703 kWh
Therefore, the whole deviation approach includes both conservative analytical approaches to determinate the net electricity generation supplied by the project activity to the grid as:
(A)Electricity at Quilleco power plant(M3+M4) = 139,028,755 kWh
(B)Losses = 1,309,180 kWh
(A-B)Electricity at the injection point (Quilleco Substation) = 137,719,575 kWh
(C)Electricity consumption for Auxiliary Services(M5+0.2%) = 1,378,703 kWh
(A-B-C)Net electricity Generation = 136,340,872 kWh

The project participant (PP) would like to kindly ask the Executive Board to consider both corrective actions as satisfactory to comply with the monitoring procedure for the period the deviations, from July 9th 2008 to August 14th 2010.

AENOR determined during the verification process that project participants deviated from the provisions of the registered monitoring plan because the data of the parameter “Generationh” was not obtained correctly as consequence of:
• The lack of registered measured values from the primary meters from July 9th 2008 to August 14th 2010.
• The meter for measurement of auxiliary services consumption was not properly verified for accuracy.
Both issues were corrected by the project participant and:
• The readings of the primary meters have being continuously recorded since August 15th 2010.
• The meter of auxiliary services consumption was replaced on August 13th 2010 by a properly calibrated new one.
Therefore, AENOR considers that the requested deviation does not require an amendment to the Monitoring Plan of the registered PDD because the requested deviation only affects a specific period from 9/07/2008 to 14/08/2010, and the monitoring of the parameter “Generationh”, affected by the requested deviation, is according to the Monitoring Plan of the registered PDD for the period from 15/08/2010 to 8/07/2015 (end of the first crediting period).

For the period of the deviations, from July 9th 2008 to August 14th 2010:
• As consequence of deviations, the value of the parameter “Generationh”, before applying the proposed deviation approach, is currently determinate as Electricity at Quilleco power plant (M3+M4) minus Electricity consumption for Auxiliary Services (M5):
Generationh,dev = (M3+M4)-M5 = 139,028,755 kWh – 1,375,952 kWh
Generationh,dev = 137,652,804 kWh
• However, the value of the parameter “Generationh”, taking into account the proposed deviation approach (based on both conservative analytical approaches) is calculated as:
Generationh,dev app. = (M3+M4)-losses-(M5+0.2%M5)
Generationh,dev app. = (139,028,755 - 1,309,180 - 1,378,703) kWh
Generationh, dev app. = 136,340,872 kWh
After concluding the period of the deviations, since August 15th 2010, the value of the parameter “Generationh” will be determinate, according to the registered Monitoring Plan, as the electricity generation supplied by the project activity in the interconnection point and measured with primary meters (M1 and M2), minus the electricity consumption for auxiliary services of the project activity and measured with meter M5 (M1+M2-M5):
Generationh = 138,315,228 kWh - 1,375,952 kWh = 136,939,276 kWh
The impact of the deviation approach is estimated comparing the outcomes of the approaches used with the actual measurement data of M1 and M2 is available for the period from August 15th 2010 to December 31th 2010.
Generationh, dev app. = 136,340,872 kWh
Generationh = 136,939,276 kWh

Based on this comparison, the impact of the deviation approach over the “generationh” of the registered Monitoring Plan is estimated as:
(Generationh - Generationh, dev app.)/ Generationh = 0.44%

The net electricity generation calculated with the proposed deviation (based on both conservative analytical approaches) is 0.44% lower than the electricity obtained based on the actual measurements (M1+M2-M5).
According to the registered PDD, the emission reductions are determinate as:
ERy = BEy − PEy − Ly = BEy = EFy * Generationy
Hence, as consequence of the lower value of the net electricity generation obtained with the proposed deviation, it is expected to rather result in a slight underestimation of the emission reductions, demonstrating the conservativeness of the whole deviation approach.