POWER January 2012 - 60

PLANT O&M
Navigant Announces Coal-Fired
Generation Operational Excellence
Awards
Navigant's Operational Excellence Awards are presented annually to those
North American coal-fired generation plants that have demonstrated excellence
in cost-efficient reliable plant performance over the preceding
five-year period. The data used to select the winners derives from Navigant's
Generation Knowledge Service fossil database.
By Dale Probasco and Bob Ruhlman, Navigant Consulting Inc.
E
lectricity produced from coal combustion
remains the foundation of the U.S.
power generation system. According to
the latest available data from the U.S. Energy
Information Administration, coal-fired generation
accounts for 30.7% of the nation's
installed capacity yet produces 45.9% of
the electricity sold in the U.S., based on net
summer capacity. The high reliability and affordable
cost of electricity produced in large
scale from coal has fueled the growth of the
U.S. economy and has facilitated many technological
advances, which in turn stimulates
productivity.
To recognize the contribution of coal-fired
electricity to our society, Navigant presents
annual Operational Excellence Awards to
three plants each year, based on average unit
size:
■ Small plant: average unit size less than
200 MW
■ Medium plant: average unit size 200 MW
to 500 MW
■ Large plant: average unit size greater than
500 MW
The slate of candidates is taken from those
plants that have made continuous data submissions
to Navigant's Generation Knowledge
Service (GKS) for the entire five-year
evaluation period. Navigant's GKS database
contains detailed, unit-level cost and reliability
data on more than 2,000 generating units
representing more than 400 GW of capacity.
The award selection criteria are designed
to identify plants that best demonstrate the
following characteristics:
■ Efficient nonfuel operation and maintenance
(NFOM) cost management
■ High availability
60
■ Improving reliability trend
■ Predictable reliability performance
Efficient NFOM Cost Management.
Efficient NFOM is measured using Navigant's
Normalized Cost Index (NCI), which
is the ratio of a plant's actual NFOM cost to
the predicted cost for the five-year evaluation
period. The evaluation also ensures that
there are no unusual circumstances affecting
the evaluation (such as plants significantly
altering their financial and/or operational status
due to announced unit retirements). Additionally,
NFOM costs include replacement
capital to better provide an apples-to-apples
comparison.
Predicted cost is based on a unit-level
NFOM multivariate regression model that
includes more than 500 coal units. The cost
model utilizes anywhere from eight to 10 statistically
significant independent variables,
including unit size, boiler cycle technology,
fuel characteristics (such as heat content and
percent sulfur), scrubbed/unscrubbed, and
utilization.
The model is very reliable, exhibiting an
adjusted R-square value of anywhere from
88% to 92%. To determine the NCI value for
any given plant, the actual NFOM plant level
spend is divided by the sum of the individual
unit-level predicted NFOM values. NCI values
>1 suggest that the actual NFOM spend
is greater than the predicted value, whereas
values <1 suggest the actual NFOM spend is
less than the predicted value. For each plant
size category, the plant-level NCI values are
ordered from lowest to highest to determine
the plant rankings for efficient NFOM cost
management.
High Availability. A plant-level equivalent
availability factor (EAF) is calculated
www.powermag.com
for the previous five-year period according to
the NERC/GADS weighted (capacity-based)
performance index pooling unit calculations
specified in Appendix F of the GADS data
reporting instructions. The plant-level EAF
values are ordered from high to low within
each plant size category to determine rankings
for the availability component.
Improving Reliability Trend. This evaluation
component seeks to reward plants demonstrating
improvement in their reliability
over the five-year evaluation period. Equivalent
unplanned outage rate (EUOR) was chosen
because it incorporates derates and both
forced and maintenance outages and is based
on actual demand similar to the equivalent
forced outage rate (EFOR) calculation. A
quarterly plant-level EUOR value is calculated
and plotted over the five-year period. The
slope of the simple regression line is used to
quantify the rate of improvement or degradation
in plant reliability. A negative slope indicates
an improving trend in reliability, while
a positive slope indicates a degrading trend in
reliability. The regression slopes are then ordered
from low to high in order to determine
the plant rankings in the improving reliability
category.
Predictable Reliability Performance.
This component captures the negative impact
that high-impact/low-probability (HILP)
events have on overall plant performance. It is
a subtle measure and is not weighted heavily
in the overall rankings relative to the three previously
listed components. The impact of this
component is determined by measuring the
amount of variability that exists in the quarterly
EUOR data mentioned above. Higher measures
of variability are usually associated with
HILP-type events. The variability measure is
ordered from low to high in order to determine
the plant rankings for this category.
POWER | January 2012
http://www.powermag.com
POWER January 2012

Table of Contents for the Digital Edition of POWER January 2012
