Mark, as per our discussion I will require the Feb. curtailment at Clear Sky 
to calculated using the same methodology as was used in the latest March 
calculation. This data is required for the March owner report which must be 
sent to the owner today.

Thank you very much for your understanding and support regarding this issue.

KA  




Mark Fisher
04/19/2002 09:07 AM
To: Jay Godfrey/EWC/Enron@ENRON, Kurt Anderson/EWC/Enron@ENRON, Bo 
Thisted/EWC/Enron@Enron, Hollis Kimbrough/EWC/Enron@ENRON
cc:  

Subject: CLear Sky/Trent Comparison






Explainations:

Predicted: For each 10 minute interval and each turbine the wind speed was 
converted to a power. The power for each 10 minute interval was then 
averaged, to produce a mean power for the site. This number was then scaled 
by the number of turbines to produce a site wide power value, that value was 
then converted to an energy value.

Curtailment: Curtailment logs were provided by the site giving the turbine 
number and the start and stop time of the curtailment. For each curtailment 
period the wind speed was found. Due to the fact that wind speeds are lower 
on non-producing turbines, the wind speed was scaled up by approximately 5%. 
This wind speed was then converted to power, and then energy. The value of 
the curtailment number is the sum for all curtailments. 

Unavailable: The Curtailment value was removed from the predicted production 
and the result multiplied by the site availability.

Difference: This is a sum total, removing the Curtailment and unavailable 
from the predicted.

Line loss: This is 98% of the Difference to estimate a 2% line loss.

Net: Is the difference of Difference and line loss.

Actual: Is taken directly from the Substation

Variance: Is the difference between the Net and Actual



Curtailed production: Is the amount of  energy not produced due to 
curtailment.
97% Availability: Is 97% of the curtailed production.
2% line loss: Is 98% of the value in 97% availability

Billable Curtailment: Is the value for Curtailment after both availability 
and line loss are taken into account.