Spare parts critical for stable power generation

Article and photos by Amy Echols, Public Affairs Office

A spare, but critical, $12 million transformer (foreground) on the lower deck of Bonneville’s second powerhouse stands at the ready to move into place should one of the others fail. (Photo by Amy Echols, Public Affairs Office)

A spare, but critical, $12 million transformer (foreground) on the lower deck of Bonneville’s second powerhouse stands at the ready to move into place should one of the others fail. (Photo by Amy Echols, Public Affairs Office)

Here is a familiar story: your car breaks down. It’s towed to a shop for repairs. You learn that the necessary parts are not in stock and will take two weeks for delivery from a distant warehouse. A rush job will cost twice as much and the situation puts you on public transportation for a while.

While auto repairs are a personal inconvenience, much worse ensues when generator bushings fail or a transformer stops working at a U.S. Army Corps of Engineers powerhouse. Replacing large, key parts can take from many months to several years, spurring a loss in production and potential impacts to consumers.

A collaborative, multi-agency Critical Spares initiative among the Corps, the U.S. Bureau of Reclamation and the Bonneville Power Administration (the three agencies that comprise the Federal Columbia River Power System) is improving some business practices by strategically building a reserve of these parts for critical hydropower assets, such as turbines, generators and transformers. Their goal is to be prepared for the unexpected failure of essential equipment and the speedy replacement of aging equipment that surpasses its usefulness.

“Aging equipment increases the power system’s risk of failure,” explained Sondra Ruckwardt, who manages Portland District’s hydropower assets funded directly by BPA. “Much of our power train equipment—turbines, generators, bushings—is made from components manufactured around the world, not unlike the cars we drive today. With that, it can take many months, even years, from our order to delivery through the installation of these huge parts.”

The Critical Spares process begins with inventories at Corps and BOR dams to identify the condition of critical equipment and prioritize each part’s value to the Columbia River’s federal hydropower system, including power production, safety and the environment. The agencies then evaluate the risk of the equipments’ failure, calculated by weighing the probability of something going wrong against the resulting consequences. Team members, including engineers, contract specialists, operations staff and resource managers, research and document lead times for the manufacturing and delivery of replacement parts. All combined, this information guides investments to build up an inventory of “critical spares” in key locations around the system of federal dams.

Traditionally, Portland District warehouses stock a variety of parts but changing business conditions call for a reduction in inventory of the less-significant parts that don’t take much lead-time to manufacture. Conversely, increased access to more complicated spares (“essential exceptions” in operations business lingo) minimizes the loss of productivity. Typically, these parts take more than three months lead-time to acquire.

Dennis Schwartz, co-chair of Portland District’s Large Capital Program, checks over critical spare transformer bushings at Bonneville’s second powerhouse. (Photo by Amy Echols, Public Affairs Office)

Dennis Schwartz, co-chair of Portland District’s Large Capital Program, checks over critical spare transformer bushings at Bonneville’s second powerhouse. (Photo by Amy Echols, Public Affairs Office)

The failure of one transformer at a large dam like John Day puts a stop to several powerhouse generators and managers must divert resources, including staff, to other activities. Currently in stock, a spare transformer on the deck of the powerhouse will eliminate the lengthy contracting, manufacturing and related efforts to acquire a spare. Generation can resume without extended power loss. In addition, the compatibility of this spare transformer is a key part of the Critical Spares initiative as well—Walla Walla District projects on the lower Snake River can use this same unit should the need arise.

“We weigh the cost of building up a more expensive critical spares inventory, including the maintenance and storage of spare parts, with the benefits of a more resilient system,” said Ruckwardt.“

The failure of a transformer at Bonneville’s second powerhouse will reduce its generating capacity by 50 percent. The unit weighs more than 282 tons, including oil and an oil tank, so just removing it would take several months,” said Dennis Schwartz, co-chair of Portland District’s Large Capital Program. “But that is nothing when compared to the three years it can take to manufacture, assemble and deliver a spare. Then add a few months to get it working at the dam.”

With a large inventory of original and aging power train equipment in Portland District, the $12 million spare transformers already on site at John Day and Bonneville dams are considered investments in efficiency.

Schwartz said that the initiative also establishes contracting and other mechanisms to acquire spares and adds to current successful business practices around the Corps. “So when a part is shipped off to the graveyard at the end of its life, this effort will help keep the region’s system at peak performance.”