Delegating operation and maintenance to your supplier can deliver savings on multi-unit or single sites. Wärtsilä is applying a condition based monitoring and maintenance approach to achieve this for its customers.
Tomas Ràƒ¶nn & Johan Pellas, Wärtsilä, Finland
The overall measure of a power plant’s operational success and commercial viability is its life cycle effectiveness. This incorporates several goals such as lowest life cycle cost, highest possible efficiency and the ability to meet environmental targets. The concept comprises two key categories of measurement: the performance of the equipment and the personnel operating it, and the factors that make up the equipment’s operational availability.
Asset management is an effective business solution to control a plant’s operational efficiency performance. An all-inclusive operations and maintenance (O&M) agreement for the running of a power plant is a comprehensive form of asset management. The O&M contractor is not only maintaining the asset but is ensuring the plant is operated at optimum levels of performance to produce energy at the lowest possible cost for the owner.
Figure 1. Reports CBM centres analyze and evaluate operational data daily, or more frequently if required
When a system is new, the equipment performance is usually at its highest. After this point the task of ensuring optimum performance becomes the task of the plant’s owners and the team they employ to oversee the running of operations.
Operational availability is the key to the asset’s business success as outage costs can be extremely damaging and have a negative effect on the bottom line. The operational availability is the percentage of time that a system performs, or is ready to perform, satisfactorily in an operating environment.
The running cost of a power plant depends heavily on its technology, size and location. The costs are typically: O&M 12 per cent, fuel 50 per cent, repayment and interest of loans 30 per cent and other costs eight per cent. For the owner many of these costs are difficult, if not impossible, to predict, making asset costing forecasts a hazardous task.
The process is made more accurate if the O&M contractor can provide guarantees that provide hard facts and figures for some of the running costs. The power plant’s day-to-day operations and maintenance represent key factors in the asset’s operational costs. The original equipment manufacturer (OEM) should be able to give a fixed contract price for a comprehensive O&M agreement.
Compared to the plant’s total costs, the O&M contract cost is rather small, but the day-to-day performance of the O&M contractor will play an important role on the long-term profitability of the asset. For instance, while the O&M contractor cannot guarantee fuel prices, it can guarantee the plant’s efficiency. Also, the contractor cannot alter the existence of loan repayments but it can have a positive effect on the loan’s interest rates. Additionally, the O&M contractor cannot guarantee the stability of the insurance market rates but the O&M agreement can positively impact on preferential low premiums for the power asset.
When the OEM is contracted to carry out a power plant’s O&M functions, the plant owner or manager has a long term fixed price for the operations and maintenance of the asset and its energy production.
The O&M contractor also provides performance guarantees for availability, heat rate, output, etc. and will pay liquidated damages to the owner if the performance is not met.
Efficiency improvements are implemented more swiftly and access to the correct spares and parts is made simpler. In this manner the O&M contractor is ensuring that the asset maintains its value and operational effectiveness.
Lenders and insurers often grant reduced premiums as a direct result of an O&M contract with an experienced OEM contractor. These reductions are due to the fact that these O&M contracts represent risk hedging by both the lenders and insurers. The fact that a company’s power plant asset is covered by an O&M contract, from the OEM, means that the financial markets will have more confidence in the asset’s long-term efficiency and its future financial performance as well.
An O&M contract also offers effective solutions to one of today’s major problems for asset managers – staff. It is essential that operating staff posses the right levels of technical competence to provide the efficiencies required, plus the numbers of staff employed must be economically viable.
The staffing problems caused by operational fluctuations can be affected by many factors such as new technologies being introduced by equipment suppliers, or by the company restructuring because of market conditions, or even a new generating plant being installed.
An O&M contractor often provides all staff required to operate a power plant asset. This provides better flexibility because a contractor is typically operating many plants with broad range of differing technologies and can quickly add staff competencies or reduce and relocate staff.
The Finnish based company Wärtsilä has developed specialized functions that can assist the managers of a power plant in operating their asset. Firstly, there are the service projects that specialize in the plant modernization, which brings older plants up to today’s technical standards. Then, there are the O&M projects, which specialize in all of the tasks needed to operate and maintain power plants world-spanning.
Figure 2. A condition based approach can result in longer maintenance intervals and resultant cost savings
As new technologies are introduced for power plant operations, it is essential for the plant’s management to optimize these technical solutions to ensure their asset continues to perform at the highest efficiencies that can be achieved.
Since the relative life cycle effectiveness changes over the years due to the new technological developments and the introduction of more efficient solutions, a plant may need several ‘re-vitalising’ packages to perform optimally throughout its long lifetime. These upgrades would be recommended and implemented by the O&M contractor, thus ensuring the plant continues to be a valuable asset.
As is usually the case with older plants, the asset’s own automation systems often need modernization alongside the new technologies being implemented. Wärtsilä has recognised this need and has the capability to perform electrical and automation modernization. Upgrading of the various systems is based upon proven solutions using standard Wärtsilä modules and system components designed to meet client needs and demands.
A regular power system analysis is becoming an increasingly important management tool for optimizing the performance and efficiency of a power asset. Measurement systems should preferably employ the latest technology in order to keep up with today’s requirements and tomorrow’s challenges in monitoring and data collection.
Environmental aspects are another important consideration, especially the need to obtain accurate information on vital energy production parameters to keep the plant within environmental limits.
An electrical and automation service package helps to safeguard the plant against interruptions in power distribution. The package offered by Wärtsilä contains complete engine function tests with running sequences including safety systems and controls. All sensors, transducers and meters are calibrated.
An automation modernization package, also offered, brings an older installation up to the latest technical standards. In many cases this means adopting digital in place of analogue systems. If not already present, remote connections with data acquisition systems can also be installed. Wärtsilä can provide specialized systems covering data acquisition, fault analysis, planned maintenance and technical information for the asset management team.
Other effective asset management solutions for power plants and marine installations, which can also be linked to O&M operations, are known as condition monitoring and condition based maintenance (CBM), both are aimed at getting the most out of an installation at the lowest possible life cycle cost. Productivity and profitability demands, new environmental regulations, and increasingly sophisticated equipment have all combined to push power companies to invest in efficient and cost-effective maintenance programmes to maximize the technical and economic performance of their installations.
Although preventative maintenance, typically scheduled maintenance, is a safe approach for keeping installations and equipment in shape and avoiding unplanned stops, it will not always ensure optimized equipment availability because of its generic nature, in addition to being labour intensive.
Traditional maintenance programmes usually involve visual inspections of certain components, thus requiring the equipment to be shut down and dismantled. When operational availability is critical, for example when any downtime will result in substantial revenue losses, any equipment outage must be avoided or minimized. In contrast, a maintenance programme that can predict incipient failures and continuously address a real maintenance need is therefore a more effective approach to cutting costs and increasing the safety and operational availability of equipment.
The CBM programme
Each installation has its own unique operating environment. This includes an operation profile, fuel type, load pattern, ambient conditions and many other factors, all of which influence the operation as well as the maintenance programme.
CBM optimizes operational availability according to the customer’s business needs by grouping maintenance tasks in an optimal way. CBM incorporates, rather than replaces, scheduled maintenance knowledge; when determining the equipment condition engineers, as well as computer programmes, still need to draw comparisons with real life reference cases or experience.
Nor is CBM about extending maintenance schedules. Instead, it places maintenance where it is most beneficial – in some cases earlier than stipulated in the preventive maintenance schedule, in some cases later, adapting to the customers’ operational availability scheme.
A CBM programme can include purely technical solutions, such as computing power that facilitates an instant awareness of equipment conditions, as well as remote monitoring and also advisory services. The programme affects more than just direct costs. It can also reduce the negative consequences of maintenance practices that may not be so easily quantified.
CBM would not be possible without monitoring the operation parameters. Determining current equipment operating status is possible today by utilizing modern control and monitoring systems such as the Wärtsilä Operator’s Interface System (WOIS) and the Wärtsilä Information System Environment (WISE) solutions in combination with modern communication technology and advanced CBM analyzing solutions.
Wärtsilä’s range of services is aided by a condition monitoring process with remote CBM centres capable of analyzing and evaluating operational data daily, or more frequently if required. Various alternatives are available for data capture and data transfer.
These include the Internet with Virtual Private Networking (VPN), which also offers the possibility of online monitoring, automatic, or manual e-mail transfer, or satellite communication. By connecting to the Wärtsilä website, users can access CBM information (the web service is only available for installations connected to the CBM centre), service bulletins, technical manuals and spare parts online.
Optimized operation and correctly tuned equipment keep operating costs at a healthy level. Remote monitoring, including the proper CBM solution, supports operators in their day-to-day operation of the installation by applying the company’s vast experience and operational knowledge. This helps to keep the plant’s thermal and mechanical load at the design level for the actual operation conditions. It also enables savings in fuel consumption while simultaneously reducing NOx, COx and SOx emissions, providing a more environmentally friendly operation.
CBM and remote monitoring are important service support functions for land and marine engine installations as well as Wärtsilä’s O&M activities. Minimal arrangements are possible when the latest in remote monitoring supports a plant’s operations. With fewer site personnel, experts can concentrate on one location and track several plants, providing advice as needed. Feedback and recommendations are supplied regularly (in urgent cases, immediately) to the owner/operator, the installations and the local Wärtsilä service office.
The analyzing programmes used by the CBM centres take into consideration the technical design data of the specific engine and installation, the ambient conditions and the engine load. The measured operation data is automatically compared with the calculated ideal operating data. If the measured operating data are outside the calculated (pre-set) ideal operation data window, the system will give an early warning, and an indication of possible reasons.
At the same time, trend prognostics can identify the corrective action to be taken and when this is required. The early warning or alert indication is sent out well before the real alarm set value is reached, thus giving more time to plan maintenance actions.
The operational concept of CBM is well established within the power and marine industries and is expected to be further developed which will make it an integral part of daily operation for many power plants and marine applications around the world. Wärtsilä’s offerings range from normal engine technical follow-up and reporting, to automatic data analysis (e.g. CBM) via remote plant service and prognostics.
Figure 3. CBM combines with remote monitoring to maximise plant operation
In February 2001, the first power plant (a Wärtsilä 18 cylinder 32LN engine located in Portugal) was connected to the CBM service system, and the first marine installation was connected in November of the same year. By the end of 2004, 54 installations with 250 engines were connected to the Wärtsilä CBM system. Currently there are agreements with some 100 installations and more than 300 engines connected or to be connected to the system during 2005.
In the set up for CBM, all operation related data (covering pressures, temperatures, load, speeds, and ambient conditions) are measured by the WOIS system and transferred via the WISE system, or by partly utilizing existing control monitoring systems, to the remote monitoring CBM centre in Vaasa, Finland. Most monitoring and supervision systems delivered today can be upgraded with automatic data transfer to supply the necessary information to the CBM centre.
The data quantities captured from the site depend on the communication set up chosen. They include:
- Automatic data capture and on-line monitoring over the internet
- Automatic data capture and collection via ISDN
- Automatic data capture and e-mail despatch from the plant
- Automatic data capture and semi-automatic e-mail despatch from the plant
- Manual data collection and sending via e-mail.
Logically, the chosen communication set up will have an impact on the frequency with which the data processing, analysis and prognostics occur. With many installations, sending or retrieving a batch of operating data once a day is sufficient to address the real maintenance need, thereby cutting costs and increasing the safety and operational availability of the equipment. In these cases, the reports are then produced according to a bi-weekly or monthly schedule.
Of course, if the daily data processing and analysis reveal that something requires immediate attention the installation is notified immediately. Typically, monthly reports are sent to the customer by e-mail as well as being available via Wärtsilä Online services on the Internet.
The energy market of today has moved from the traditional, big centralized solutions of yesterday towards a more decentralized energy production, often resulting in low manned or even unmanned plant operations. Taking this into consideration, Wärtsilä enables its remote monitoring system to alert standby maintenance personnel to any major problems at the plant.
From portable workstations, they can connect with the power plant, investigate the situation and recommend or take the necessary action. In turn, Wärtsilä can also make use of the service, which helps it maintain parts of the control systems and also remotely assist customers with fault tracing and problem solving. When problems can be diagnosed and corrected in minutes instead of days, it becomes apparent how substantial savings can be made.
The future of power generation is and will be more about the business of power. An asset’s costs and returns will be more and more in the management’s thinking and decisions. Investments will be considered in both the short term and the long term. The power industry is already seeing a heavy swing towards the life extension and modernization of an asset rather than the energy companies entering into expensive and long-term investments for new greenfield projects.
Plant services, such as outsourced O&M contracts, that save time, effort and money for the plant will become even more important factors in asset management thinking, planning and investment. The effective running of their power asset, which provides them with the best life cycle costs, will be their primary goal.