The Electric Power Research Institute is recognizing the work of BPA’s Natasha Gentry and Brett Bowers that is resulting in an increase of 7-15% of transmission capacity on thermally limited lines. Their work, along with the efforts of four other utilities – CenterPoint Energy, Great River Energy, Powerlink Queensland and Transgrid – to optimize transmission capacity will have impacts across the energy sector. Photo by Sandhu Deep, Transmission Services
Across our nation, electric grids are often operated conservatively to reduce the risk of over-taxing transmission systems and experiencing a failure, or blackout. The amount of electricity transmission lines can safely carry varies due to a number of complex and environmental factors. But overly cautious assumptions about the capacity of transmission line ratings can prevent a grid from being used most efficiently and potentially result in less revenue. Is there a better way to operate the grid while avoiding unnecessary risk?
That’s a problem two BPA employees, Natasha Gentry and Brett Bowers of the Transmission Lines and Civil Works Engineering organization, have been trying to resolve. Their work and collaboration with four other utilities – CenterPoint Energy, Great River Energy, Powerlink Queensland and Transgrid – to optimize transmission line capacity was nationally recognized recently by the Electric Power Research Institute with the EPRI Technology Transfer Award.
Gentry has been leading the efforts to update rated transmission line capacity while also reducing the risk of exceeding transmission line limits. Historically, BPA transmission line ratings are based on maximum and minimum ambient (air) temperatures in the Northwest that were based on studies conducted in the 1960s. This approach often resulted in overly conservative ratings. Gentry and Bowers took a different approach, focusing on fine-tuning transmission line ratings without exposing BPA system to a risk of overloading.
“In the last 10 years, we went from ‘this is how we’ve always done it’ to ‘there might be a better way’ to ‘how do we implement this technology in a safe and reliable way to harness its benefits?’” said Gentry, a supervisory general engineer. “We are now at the point of better understanding the capabilities and risks of that technology. And we are working on minimizing the risks to enable BPA to use our system more efficiently and effectively.”
Bowers agreed, noting that emerging technology played a key role in the development of a solution to the problem.
“In the past, there wasn’t a way for BPA to increase line ratings without increasing risk,” said Bowers, a mechanical engineer. “The new technology and insights it provides is helping remove uncertainty, so we can work toward safely increasing the utilization of our system.”
Leveraging the seasonal data and current weather conditions, they have developed risk-based assumptions that are expected to result in an average capacity increase of 7-15% on some thermally limited transmission lines.
Updating the rating methodology and the resulting increased transmission line ratings will enable BPA transmission operators to manage the system closer to its operating limits. That means more capacity will be available on the transmission lines than was previously determined and will allow for additional sales of transmission capacity to customers.
“This is an amazing breakthrough and one that will enable us to delay upgrades or new builds to accommodate an increasing need for capacity,” said Mike Miller, vice president of Transmission Engineering and Technical Services. “That will equate to millions of dollars in savings over the years. Natasha and Brett’s contributions to this effort will also make an industry-wide change.”
Improved transmission line ratings guidance is being developed through collaboration with EPRI and other engineering groups within BPA. Gentry and Bowers’ research was expanded to include studies using real-time monitoring in strategic locations to address ongoing challenges in high load areas. These findings will be shared with other utilities to help improve the understanding of real-time rating monitors and reduce operating risks by the utility industry, expanding the impact to electric grids beyond the BPA service area. EPRI has extended the development of this work through 2024 and will work with BPA to implement Gentry and Bowers’ new methodology on selected transmission lines.
“BPA’s transmission system is a huge asset for the entire Pacific Northwest. It is the super highway that delivers clean energy from hydro and other renewable energy projects to homes in several states. It is exciting for me to be a part of making that super highway run more efficiently and effectively,” Gentry said. “It is also incredibly humbling to know that our work doesn’t just benefit the Pacific Northwest but can be applied by utilities all around the world, and will hopefully result in lower energy prices, prevent blackouts and improve quality of life for others.”