Enron Mail

From:hollis.kimbrough@enron.com
To:mark.fisher@enron.com, mark.walker@enron.com, jeff.duff@enron.com
Subject:Calculating "Vestas Availability"
Cc:
Bcc:
Date:Wed, 15 May 2002 00:40:00 -0700 (PDT)

Guys,

In an earlier e-mail Ben made the statement: "Have you been able to
determine what these numbers would look like using Vestas' definition of
availability: Hours of Wind Turbine in Operation mode X 100 / Hours of Grid
in Operation Mode."

We now need to develop a methodology to calculate the Vestas definition using
VisuPro data. I think this boils down to:

Vestas Avail = (SOT+WOT+EST+RT+MT)/(ST-LOT)

Where:

SOT = System Okay Time
EST = External Stop Time
WOT = Weather Out Time
LOT = Line Out Time
DT = Down Time
RT = Repair Time
MT = Maintenance Time

ST = SOT+EST+WOT+LOT+DT+RT+MT

This calculation is based on an operating assumption that the current day
machines are placed into "pause" mode during maintenance and repair time. As
a result the availability counters will continue to increment even when the
turbine is being serviced.

Let's get together and discuss,
Hollis