The Art and Science of Outage Management

A natural gas-fired, combined-cycle power plant is a high-performance machine that runs intensively under very demanding conditions and requires periodic detailed maintenance to perform effectively and safely. This maintenance time is usually referred to as an outage.

Rocksavage in the U.K. is the oldest power plant in the InterGen fleet. Its highly skilled team has managed a number of gas turbine outages in the period between commercial handover in July 1998 and the resolution of a number of plant issues in 2003. Despite the experience gained from these overhauls, the one Rocksavage completed in December of 2005 was its most challenging to date.

In addition to undertaking the removal and replacement of high pressure steam headers, the plant’s commercial requirements mandated that both gas turbines and the steam turbine be overhauled at the same time.

In order to a get a picture of the magnitude of this undertaking, imagine a core staff of 31 individuals overseeing 400 contractors, working on a seriously time-constrained 24 hour-a-day/7 days-a-week schedule on a 17 acre outdoor site. Add to this two enormous on-site gantry cranes lifting 120 ton pieces of equipment in driving wind and freezing conditions, and the logical question follows: How does the team meet its time commitments, ensure top quality work, maximize all the opportunities the outage presents and safeguard all people involved?

According to Rocksavage Plant Manager Andy Shearman the answer can be found in meticulous planning, organization and implementation. "We were planning this outage for 18 months before we even started," he said. "We’ve utilized the most advanced planning tools and methods possible to plot and control the many thousands of outage activities, drawing upon lessons learned from the entire InterGen fleet."

Andy also cites an enormous amount of interdisciplinary teamwork as another key to success. "We’re very fortunate to have had skilled individuals from Rijnmond, Coryton, Spalding, and Corporate as core members of our planning and execution team."

According to John Proctor, Asset Manager, the Rocksavage team has taken planning to an impressively sophisticated level, "People tend to treat a traditional outage as an extended maintenance window to facilitate the replacement of worn parts. At Rocksavage, they have turned the outage into a full-fledged project management exercise addressing all the challenges of design, procurement, mobilization, construction, pre-commissioning and transition back to operations."

John noted that at each phase there was active involvement of the entire outage management team led by Andy Shearman and Kevin McGrath who were critically supported by additional resources including a Critical Path Analyst, Access Coordinator and Safety Planning Supervisor. "These guys focused night and day on creating solutions not excuses, and it is a testament to the entire team’s intelligence, creativity, and effort that they drove all the critical and sub-critical paths necessary for the on-schedule return to service," he said.

As part of the extensive planning process, the Rocky team put together a Key Risk Matrix that identified weather as the number one risk to the outage process in terms of both timeframes and safety. As such, they developed a pre-outage plant modification program that optimized sliding roof mobility and on-site structures to best streamline crane work.

They also worked intensively with HSE Manager Ian Jennings to develop and implement a rigorous outage-specific safety program to ensure the wellbeing of 400 on-site contractors.

There were also the physical logistics of keeping those contractors warm, nourished, rested and motivated that had to be planned – as Andy noted, "The ordering and serving of 250 pizzas in one night is a project to be managed in itself!"

Good will gestures, a safety award scheme, 1,000 mince pies and an incalculable amount of tea and coffee went into creating an active on-site culture where safety was paramount and each individual contribution was valued.

The results of the Rocksavage team’s efforts speak for themselves. Not only did they accomplish all of their outage objectives and bring the plant back online and commercial within the prescribed timeframe, but they did so while achieving the monumental milestone of one million man-hours worked without a single Lost Time Incident (LTI).