EP 1130-2-510
13 Dec 96
(1) Rewind In-Kind. This alternative consists of a scheduled acquisition and installation
of a new generator winding.
(2) Rewind with Uprate. For reports where uprating of the winding is being considered
(i.e. a non-incidental increase in the nameplate capacity) the analysis must demonstrate that the
additional benefits of the uprate exceed the additional costs (incremental justification).
(3) Purchase Spare winding. In this alternative, a spare winding is acquired. Installation
of the winding occurs only when the unit fails and can no longer be repaired. This alternative
limits expenditures in the budget year, and minimizes unit outage time when failure occurs, and
unit rewind is required.
(4) Combinations. If more than one unit at a plant is being considered for rewind,
combinations of rewinds and spares should be evaluated.
{5) Exclusions. While the following alternatives are considered in Major Rehabilitation
Reports, they do not need to be evaluated for rewind letter reports.
(a) Increased Maintenance. In most cases, increased or more frequent maintenance of
generator windings will not extend the useful life and need not be considered as an alternative.
(b) Optimal Timing for Implementation. Optimization of implementation timing does not
need to be addressed; only the budget year(s) under consideration need to be evaluated.
c. NED Values. Lost hydropower production due to Scheduled and unscheduled outages
should be evaluated using NED-based economic losses (not revenues). Lost energy production,
should, therefore, be evaluated as the avoided cost of generation using a system production cost
model such as PWRSYM or PC-SAM. The report should explain how such losses have been
estimated and the methodology and model(s) employed to determine NED-based unit values of
energy and capacity.
M-3. Short Cuts/Expedited Processes. The purpose of the economic analysis is to assist in
providing sufficient justification to support a rewind action. If recent reports and analyses have
been completed for the specific project which would support the recommended rewind action,
then these findings may be summarized in lieu of conducting a new economic analysis.
Assumptions and calculations must be clearly described and the hydropower values cited must no
more than 3 Fiscal Years old from the date of the proposed rewind report submission. For
example, if a prior report used hydropower values that were developed at October 1992 price
levels (FY 1993), then they would be acceptable for a rewind report being submitted during FY
1996. If the values were developed before FY 1993, then they could not be used for a FY 1996
rewind report submission.
M-4. Analytic Tools and Technical Assistance. Several economic models, consistent with major
rehabilitation evaluation criteria, have been developed for rewind studies. Technical assistance in
conducting the economic analysis or in utilizing an existing model may be obtained through
CENPD-HDC or CECW-IWR-T.
M-2
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