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Enron Mail |
Kevin,
We routinely prepare that data and it is available for all our turbines. The problem is that the consumption/production is a net number for a 5.5 minute period so we do not know what the turbine loads are, only what they are netting. This leaves two questions: 1. What is the turbine consuming during normal operation (including standby, full power, etc) and 2. What is the potential financial liability a particular site has for consumed power. The first question we cannot answer with the SCADA data because the SCADA data is a net number. This one will require actual measurement of data to ascertain. The second question we cannot answer with the SCADA data unless the frequency of the measurement coincides with the 5.5 minute SCADA periodicity. Regarding the second question: Since we will be charged a different rate for consumed power (a "retail" rate) versus the rate we are paid for produced power (the "wholesale" rate) we cannot depend on a net metering solution with an arbitrary frequency. Taking a look at extremes by way of example: If we are netting on a monthly basis then we will never owe anything under a net metering solution. This is because in normal operation the turbine always produces more power than it consumes on a monthly basis. On the other hand if the frequency is based on a 1 minute periodicity then we will have 2 instances of individual minutes. One would be a minute in which we produced power and sold it at the retail rate and the other would be a minute where we consumed power and purchased it at the retail rate. This is because the turbine is not producing power during every minute of the month. There are an infinite number of permutations because you can set the time interval to an infinite number of values. Our current value is a net number, based on a 5.5 minute interval. If the utility is basing their measurement on a different frequency then we will certainly get a different total for power consumed, The other issue is the location of the measurement. If the measurement is at the substation then the net number is an aggregate of the wind turbines which dampens the impact of a particular turbine (good for us). If the measurement is with our SCADA system at the individual turbine then we maximize the impact if a particular turbine is down for any reason while the remaining turbines are operating (bad for us). Therefore to more fully understand the 2nd question from Mark we also need to know 2 additional points: 1. What is the proposed frequency for the metering? 2. Where is the measurement going to take place? As mentioned earlier, we can provide the net production/consumption for each 5.5 minute interval. However, I think the only way we can fully address this question is to run a test program based on the answers to these two last questions. Regards, Hollis Kevin Cousineau 05/15/2002 07:25 AM To: Mark Ratekin/EWC/Enron@ENRON cc: Mark Fisher/EWC/Enron@Enron, Mark Eilers/EWC/Enron@ENRON, Hollis Kimbrough/EWC/Enron@ENRON Subject: Re: Consumption for for GE1.5 Mark, Mark and Mark: I have reviewed the attached power curve and clearly it will not help in formulating an answer to your question. I would like to ask Mark Fisher to look at a typical installation (any one of our field sites) and give us data on kWh consumed by several turbines over a multi-month period with data arranged month by month. Perhaps one or two turbines at Monfort would be the best because we can look at a whole year of data. This would tell us what was produced and what was consumed in energy. Mark Eilers, what do you think? Regards KLC Mark Ratekin 05/14/2002 04:24 PM To: Kevin Cousineau/EWC/Enron@ENRON cc: Mark Fisher/EWC/Enron@Enron, Mark Eilers/EWC/Enron@ENRON, Hollis Kimbrough/EWC/Enron@ENRON Subject: Re: Consumption for for GE1.5 Attached is the final power curve results from the Tehachapi 1.5 Prototype, which includes the power consumption. The page was scanned from the NREL Test Report. If you have any questions or need the entire document feel free to contact me. Best Regards, Mark
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