Amir Datoo

Reliability Engineer

ARMS Reliability

adatoo@armsreliability.com

USA

As we march further into the 21st century, the power sector is undergoing a massive shift. With climate change high on the global agenda, the industry as a whole is committed to finding alternatives to conventional fossil fuel power generation. Low-carbon power sources like wind, solar and hydro are being pursued by even the most traditional power companies.

To meet this commitment to produce a certain amount of power from renewable energies, these companies have to invest significant amounts of money in new technologies and new assets. And with this comes a raft of other costs that are impacting on the bottom line – maintenance being one of the largest.

Let’s look at an example of ACME Power, a global power generation and distribution company. It recently committed to generating 25 % of its total power using renewables, and has invested $XX in purchasing 250 wind turbines and siting them in an ideal, windswept location. Each turbine is capable of producing 2.3 MW with a typical efficiency of 30 %. The entire wind farm will contribute 8 % of the total power generation for ACME Power, which at its most efficient is 450 MW.

On paper, it looks like a great investment, yet ACME Power is concerned that maintenance – as yet an unknown entity for this new technology – will prove a costly blow.

For example, in the event that significant repairs are required to one of the massive wind turbines, the crane needed to manoeuvre the turbine is very hard to come by. It can take months for a crane to become available, and the costs for transport and hourly hire are huge. What is the risk of a crane not being available? Is ACME Power better off buying one outright, sharing the cost with neighbouring companies, or shouldering the occasional, yet very expensive hire cost?

This is a typical scenario, and just one of the many factors that needs to be considered when new technologies like wind turbines are introduced into existing operations.

Any new technology brings with it a raft of unknowns when it comes to operations and maintenance. Even with strong support from the OEM and the provision of thorough training for the operations team, it is still hard to quantify costs and, more importantly, identify ways to save on maintenance at this early stage.

Figure 1. Average yearly cost comparison of the two different maintenance strategies over 20 years.

Figure 2. Average yearly impact comparison of a specific failure mode over 20 years.

RCM: Early Mapping of Maintenance Plans

Proven reliability engineering techniques are used to plot a clear path for the maintenance of new assets, and to provide management with reassurance around ongoing costs.

Reliability Centered Maintenance (RCM) is one of the most beneficial techniques to use at this point. An RCM study will determine the optimal maintenance strategy for the new assets, as well as predict the maintenance budget and spares usage over an approximate 20-year lifetime. It will also model different maintenance strategy scenarios to compare risks and improvements over this lifetime, to enable the better longterm management of the assets.

Here’s how RCM would work for the ACME Power wind turbine project. First, failure data would be gathered from a variety of sources – such as work order history, spares usage rates and interviews with the personnel responsible for maintaining the equipment. Given that ACME Power has not been using wind turbines for long, the failure data may not be all that comprehensive, but this should not be seen as a stumbling block.

Using this data, along with OEM maintenance manuals and spares catalogues, a preliminary RCM model is built with the intention of fleshing out the model during facilitations with staff. During this process, technicians and engineers can have direct input into the maintenance activities that are included, which importantly creates a sense of ongoing ownership of the maintenance strategy.

From the facilitation process, the RCM model is validated and then optimized by assessing each failure mode by the cost, safety, environmental and operational contributions to reduce cost and risk.

For example, at this point ACME Power may identify that maintenance of the main gear box used to power the wind turbine is problematic, with main gear boxes costing $300,000 and the aforementioned cranes adding significantly to the repair cost. It is here that further reliability engineering techniques, like Root Cause Analysis – may be deemed necessary to make further improvements to the maintenance strategy.

Figure 1 shows the outcome of the RCM report for ACME Power. The first column shows what their existing strategy will cost per year; while the second shows the optimised model. The latter delivers $46,000 savings per year, or close to $1 million over 20 years for each turbine.

Figure 2 shows the actual impacts of a specific failure mode, where we can see that the optimised strategy has dramatically reduced the effects and costs associated with this failure mode.

Long-Lasting Benefits

An RCM study will deliver long-lasting benefits for any organization that has invested in significant new technologies. Tangible savings are delivered through the reduction in unplanned downtime, the avoidance of production losses, and a fall in risk-based costs.

It will reveal any gaps in the existing maintenance strategy and also, importantly, deliver peace of mind that existing maintenance strategies are working.

Using the right technologies and the right facilitators, an RCM study has broader benefits for operations and maintenance teams. It can boost overall capabilities by providing training and development; and integrating RCM software tools with other processes for continuous improvement. These tools can be used for the long-term forecasting of entire fleets of assets, and to empower companies to be on the front foot when it comes to contract negotiations with OEMs for maintenance.

An RCM study is a powerful technique to optimize a maintenance strategy for any new or existing asset, and delivers real savings into the long term.