Construction of any transmission line and caring for existing lines and equipment requires the collaboration of design, engineering and building talents from both within and outside the utility. External, project or owner engineers play a vital role in determining just how their products or services fit into overall transmission line design. That said, there is no substitute for the value of strong in-house engineering talent within utilities.
At the Bonneville Power Administration (BPA), we own and operate more than 15,000 circuit miles (24,140 km) of high-voltage transmission lines on more than 8,500 miles (13,680 km) of rights-of-way across a diverse territory that stretches across Washington, Oregon, Idaho and western Montana. Our in-house engineers have broad and long-standing historical knowledge about system design and other factors that could impact the system.
The Pacific Northwest has the potential of transmission system threats — ice, mudslides, seismic activity and other geo-specific threats — not posed in other areas of the country.
For instance, we have towers designed in the 1970s on which we've experienced many failures related to ice buildup. As staff engineers, we know that we need to be careful when reconductoring or adding fiber to a line that uses these towers because adding load could cause additional tower failures. Contractors may not be aware that historically the stress loads caused by ice potentially threatens these particular towers. That kind of institutional and system knowledge can help organizations avoid unplanned outages and maintain system reliability.
No in-house staff of engineers can design and maintain a system as large as BPA's without the help of external and owner engineers. In-house staff can pass on years of system knowledge to these contractors to ensure they are aware of nuanced system information. In some cases, because of our system knowledge, we have found it makes more sense to keep work in-house. BPA has areas of expertise in, for instance, lattice tower analysis and design. Another example are our fiber systems, especially on 500-kV towers. There are significant issues with electrical fields on these towers, and we have people here who have made a career of knowing these issues and getting it right all the time. Knowing what you're good at helps you to prioritize what work you should contract to outside entities.
Utility engineering staff must have expertise not only in what to do and how to do it, but also be able to evaluate the final product. Staff engineers need to have significant expertise to make sure the contract work is being done as it should.
In-house engineers also inherently understand the organization's culture more than contracted entities. BPA as a non-profit, federal entity has a goal to keep its customers rates as low as possible. Contract or owner engineers may not always approach a project from that perspective. Sometimes we might add value to a project that an outside engineering firm would not. In instances where our system knowledge contributes to project design, our savings more than warrant a robust in-house engineering presence.
One of our most significant in-house success stories to date has been a redesign of some of our steel lattice towers. A team of BPA engineers I worked with designed towers that are stronger, yet use less steel. They're also sturdier but cheaper. The icing on the cake: They're easier to assemble but better withstand winds and storms. The new designs saved BPA more than US$11 million on the McNary-John Day line, a 500-kV 79-mile (127-km) line located mostly in central Washington.
Let's say we can save 10% in project costs by using in-house engineers versus contract engineers. We have had projects that cost hundreds of millions of dollars, so if we can save 20 million on a project, the in-house staff has paid for their keep.
The Northwest is prone to significant winter wind storms that can wreak havoc on our system. When we experience major damage that requires engineers to perform or consult on system design, it has to happen quickly. This is another advantage to having seasoned, knowledgeable in-house engineers who can help save critical hours and minutes when people and public safety officials are eager to have power restored.
There are many advantages to having a robust in-house engineering staff. We are learning that turnover can take its toll though. To ensure we keep pace, we have programs to start working with students in college, and when they complete their education, they come to work for BPA. We have also learned that workload does not wait, so we have created a system to document our processes, procedures and standards so we can seamlessly pass on critical system knowledge and techniques to our newer engineers.
BPA has found immense value in its in-house engineering staff. This staff helps us save money, provide advice and counsel to outside engineers, and seamlessly train and educate new staff to ensure BPA and its customers a reliable and safe electrical future.
David Hesse ([email protected]) has been a structural engineer at Bonneville Power Administration since 1991.