University: Maintenance Planning and Scheduling in Centrica Analysis

This report presents a case study on maintenance planning and scheduling practices at Centrica, a British multinational utility company. The study analyzes primary data collected through questionnaires and secondary data from internal operational reports across hydro, thermal, and geothermal generation technologies. The research evaluates Centrica's maintenance practices, comparing them with industry benchmarks to identify areas for improvement. Key findings highlight the use of corrective, preventive, and condition-based maintenance approaches across different plant types. The report emphasizes the importance of enhanced maintenance planning and scheduling for reliable and cost-effective power generation and distribution. The study also examines benchmarks for plant availability, schedule compliance, and maintenance costs, providing recommendations for optimizing maintenance strategies and improving overall operational efficiency within Centrica. The report includes a discussion of industry best practices, the conceptual model of reliability, maintainability, and availability, along with a review of maintenance approaches such as corrective, preventive, and condition-based maintenance.

MAINTENANCE PLANNING AND SCHEDULING IN CENTRICA
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Abstract
The purpose of this project was to establish the maintenance planning and scheduling at
Centrica. Centrica is a British multinational utility company with its headquarter in Berkshire.
The case study was done with a target population of all the three operational areas with
different generation technology of hydro, thermal and geothermal. The study used primary data
which was gathered by means of a self-administered questionnaire issued to respondents and
secondary data which was extracted from internal operational reports in Eastern hydro power
stations. The average of each aspect was calculated and the quantity identified to evaluate the
maintenance practices at Centrica and to benchmark with the world best practices. The study
recommended that for reliable and competitively priced electric power in UK, there is need to
have the power utilities enhance their maintenance planning and scheduling practices for
effective and efficient generation and distribution of power to meet the customers’ expectations.
Introduction
Maintenance planning and scheduling is defined as “The combination of all technical and
associated administrative actions intended to retain an item in, or restore it to, a state in
which it can perform its required function” by British standard 3811. It includes inspection,
testing, servicing, repair and reclamation. In sum maintenance encompasses all works
carried out on a plant or a facility with the view to rectifying a defect or failure in its
functioning or performance; preventing failure in its functioning and/or improving the state
of the facility so as to sustain its utilization and value. In a production facility, maintenance
acts as a support for the production process, where the production input is converted into

specified production output. Industrial maintenance comes as a secondary process, which
has to contribute for obtaining the objectives of production. Maintenance must be able to
retain or restore the systems for carrying out a perfect production function. (Gits, 2010).
There exists asset management software’s in the market and established best world practice
benchmarks which if well utilized could reduce maintenance costs to a great extent.
Consequently, a number of surveys conducted in industries throughout the UK have found
that 70% of equipment failures are self-induced. Maintenance personnel who are not
following what is termed as „Best Maintenance Repair Practices‟ substantially affect these
failures. Between 30% and 50% of the self-induced failures are as a result of maintenance
personnel not knowing the basics of maintenance. Maintenance personnel, who, although
skilled, choose not to follow best maintenance repair practices, potentially cause another
20% to 30% of those failures (Smith, 2000).
Best maintenance planning and scheduling practices are defined in two categories:
standards and methods. Standards are the measurable performance levels (benchmarking) of
maintenance execution; methods and strategies must be practiced in order to meet the
standards. The combination of standards with methods and strategies provides the elements
of an integrated planned maintenance system. Achievement of the best maintenance
practice standards (maintenance excellence) is accomplished through an interactive and
integrated series of links with an array of methods and strategies. Maintenance planning
and scheduling is an essential part of effective maintenance. Planners must develop and
implement both preventive and corrective maintenance tasks that achieve maximum use of
maintenance resources and the production capacity of plant systems.

Operation and Maintenance Planning
Visser (1998) modeled maintenance as a transformation process encapsulated in an
enterprise system. The way maintenance is performed will influence the availability of
production facilities, the rate of production, quality of end product and cost of production,
as well as the safety of the operation. These factors in turn will determine the profitability
of the enterprise. Generally, there are four strategic dimensions of maintenance (Tsang,
2002). The dimensions start with Service-delivery options which are related with the input
some are labor, material, spares and external services. This explains the choice within the
inside capability and outsourcing. The second and third dimensions are related to the design
and selection of maintenance methodologies. The performance will play a major role on the
output, in which some are productivity output, safety, maintainability and the profit of the
whole enterprise. The last and final dimension is related to the support system which is
explained as the design that is supporting maintenance (Tsang, 2002).
The cost of inventory is almost always an area where cost reduction can be substantial. With the
help of suppliers and equipment vendors, purchasing usually can place contracts or service level
agreement that guarantee delivery lead time for designated inventory items. It just makes sense
that your facility should shift the bulk of the cost of maintaining inventory to the suppliers.
Conceptual Model
Reliability is the probability that an engineering system will perform its intended function
satisfactorily (from the viewpoint of the customer) for its intended life under specified

environmental and operating conditions. Maintainability is the probability that maintenance
of the system will retain the system in, or restore it to, a specified condition within a given
time period. Availability is the probability that the system is operating satisfactorily at any
time, and it depends on the reliability and the maintainability. Reliability is basically a
design parameter and must be incorporated into the system at the design stage. It is an
inherent characteristic of the system, just as is capacity, power rating, or performance
Skills and training plays a major role in maintenance. Most of the work is normally carried
out by Craftsmen and Technician/Foremen. Most of them have learned their skills on job
trainee on the basis of watch and learn. However, with the expansion in mechanization and
automation of machines structured technical training programs have been developed to
upgrade the skills for the maintenance teams. This is critical for an effective maintenance
practice. The competence of human resources in the maintenance department is considered
an important factor in a successful maintenance program (Nakajima, 1988; Cholasuke et al.,
2004; Kelly, 2006). Competence can be described as a combination of knowledge, skills,
ability, willingness, interest and personal characteristics. Educational resources, which can
include technical consultation as well as training, must be available and accessible to
employees with identified needs (Tsang, 2002, Elsevier, 2009)
Performing a job task analysis will help define the skill levels required of maintenance
department employees. The should be followed with a skills assessment of employee
knowledge and skill levels. Analyzing the gap between required skills and available skills
to determine the amount and level of training is necessary to close the gap.

Main Approach in Maintenance Planning and Scheduling
Several maintenance approaches, i.e. strategies and concepts, have been implemented by
practitioners or suggested by intellectuals. Maintenance approaches and their development
are discussed by many authors; see, for example (Moubray, 1991; Kelly, 1997; Mckone and
Wiess, 1998; Dekker, 1996; Sherwin, 2000; Swanson, 2001; Tsang, 2002; Alsyouf, 2007).
Usually, maintenance actions are aimed at minimizing failure and the consequences of
failure of industrial plant, machinery and equipment as far as possible. These actions can
take several forms such as breakdown maintenance, preventive maintenance, i.e. replacing
components at a pre-determined time using statistical models based on collected historical
failure data, or condition-based maintenance by monitoring the condition of the component
using one condition monitoring techniques.
Best Maintenance Planning and Scheduling in the Industry
A study by Fernando and Gilbert (2009) revealed that the availability of a complex system
such as a gas turbine is strongly associated with its parts reliability and a maintenance
policy. That policy not only has influence on the parts repair time but also on the parts
reliability affecting the system degradation and availability. Therefore, the maintenance
practices of any utility have a relationship to its plants availability performance.
Best maintenance practices are defined in two categories: standards and methods. Standards
are the measurable performance levels of maintenance execution; methods and strategies

must be practiced in order to meet the standards. The combination of standards with
methods and strategies provides the elements of an integrated planned maintenance system.
Achievement of the best maintenance practice standards is accomplished through an
interactive and integrated series of links with an array of methods and strategies. Centrica
has a computerized maintenance management system by the name Plant maintenance which
is integral to the company’s system. All the maintenance work is captured on a work order.
This includes planned/scheduled, corrective, emergency, etc. The work order is the primary
tool for managing labor resources and measuring department effectiveness. The
maintenance output provides maintenance, engineering, operations, supply chain and upper
management with accurate and effective reports for evaluation and management. The
following are types of reports and data tracking obtained from a maintenance includes: open
work orders, closed work orders, mean time between failures, cost per reports, scheduled
compliance, plant maintenance overdue, labor allocation, spare parts demand and usage
reports
Benchmarks
Item Description Benchmarking
1
Percentage of a maintenance person's time is covered by a work
order 100
2
Percentage of work orders are generated by preventive maintenance
inspections and is planned 90
3 Percentage compliance of scheduled (programmed) work is met 90

4 Percentage of scheduled work is planned 90
5 Percentage of all work is preventive maintenance 30
6
% age of the required reliability level is reached 100 percent of the
time 100
7 Spare parts stock-outs are rare <1 month
8 Percentage variation of maintenance cost from budget 2%
9 Individual training program for maintenance team per year >15days
10 Maintenance callouts per month <2
11
%age of maintenance works assigned to maintenance team on daily
basis >65%
12 Availability of technical and historical data for any equipment >95%
13 Compliant to occupational health and safety standard 100%
Table 2.4. Industry Operation and Maintenance metrics and benchmarks (NASA 2000)
Metric Variables and Equation Benchmark
1
Equipment Availability % = Hours each unit is available to run at
capacity
/Total hours during the reporting time period > 95%
2 Schedule Compliance % = Total hours worked on scheduled jobs /
Total hours scheduled > 90%

3
Emergency
Maintenance
Percentage
% = Total hours worked on emergency jobs
< 10%
Total hours worked
4
Maintenance Overtime
Percentage
% = Total maintenance overtime during period
< 5%Total regular maintenance hour during period
5
Preventive
Maintenance
Completion Percentage
% = Preventive maintenance actions completed
> 90%
Preventive maintenance actions scheduled
6
Preventive
Maintenance
Budget/Cost
% = Preventive maintenance cost
15% – 18%
Total maintenance cost
7
Predictive Maintenance
Budget/Cost
% = Predictive maintenance cost
10% – 12%Total maintenance cost
Data Analysis
Types of Maintenance Approach Used in Centrica’s Plants
Table 4.7 presents a summary of the findings with regards to the types of maintenance
planning and Scheduling approach used in Centrica plants

Type of
Maintenanc
e
Hydro
Frequency Percent
Geothermal
Frequency Percent
Thermal
Frequency Percent
Corrective 1 5.88 1 11.11 1 9.09
Preventive 9 52.94 1 11.11 4 36.36
CBM Based 0 0.00 1 11.11 2 18.18
All 7 41.18 6 66.67 4 36.36
Total 17 100 9 100 11 100
As shown in table 4.7, a mix of the 3 types of maintenance approaches namely corrective,
preventive and condition-based maintenances scored high relatively high marks from the
respondents of all the areas with Geothermal recording the highest score of 66.67%,
followed by Hydro 41.18% and Thermal at 36.36%. Preventive maintenance was dominant
in the Hydro plants recording a high score of 52.94% of their respondents.
As revealed from table 4.6 that maintenance practices which involves use of maintenance
planning and procedures, this would explain the high respondents on preventive
maintenance since these are the tools you require when carrying planned outages. A fully
establishment of a condition-based maintenance is a cost intensive exercise and the system
is yet to be established in Centrica, this would explain the low score recorded on CBM.
Corrective maintenance on the other hand is not popular and staffs are reluctant to disclose
their weaknesses hence the low score under this aspect and high score in favour of the 3
approaches.

Var Description
Centrica
Mean
Standard
Deviatio
n
Benchmar
k
%
Varianc
e
1 Plants Availability BM (95) 90.27 0.73 95 4.98
2
Percentage of daily work allocated to
staff is preventive maintenance BM
(>65%) 55.34 3.2 65 14.86
3
Variance between maintenance works
and budgeted amount BM (5%) 5.93 0.53 5 (18.60)
4
Percentage of maintenance work
carried by a work order BM (100) 73.43 3.87 100 26.57
5
Percentage of programmed work is
done as scheduled BM (90) 60.49 3.05 90 32.79
6
Percentage of opened work orders that
are closed in a month BM (100) 64.44 3.92 100 35.56
7
Percentage of work orders generated
is planned before the outage BM (90) 57.49 3.85 90 36.12
8
Technical Training days to staff per
year
BM (15) 7.14 0.65 15 52.40
9 Percentage of total overtime against 9.86 0.84 5 (97.20)

total maintenance time BM (5%)
10
Percentage of PM and CBM costs to
the total maintenance cost BM (15-
30%) 45.01 3.3 22.5
(100.04
)
11 Callouts per month BM (<2) 4.27 0.46 2
(113.50
)
12
Percentage of work orders generated
by breakdown maintenances BM (10) 44.28 4.46 10
(342.80
)
Table 4.8: Benchmarking Centrica’s Maintenance Practices with World Best
As shown in table 4.8, there were four parameters where the Centrica’s maintenance
practices variance against the world best practices were in the range from 26.52% to
36.12% close. These variables were percentage of maintenance work carried by a work
order, percentage of programmed work is done as scheduled, and percentage of opened
work orders that are closed in a month and percentage of work orders generated are planned
before the outage.