California public power utility Sacramento Municipal Utility District is using high technology tools to pinpoint, prune and remove unsafe trees and brush along sections of its rights of way to reduce potential fuel for wild fires.
As part of its year-round safety work, SMUD vegetation management crews have been removing trees with high fuel loads in high fire risk areas under and near its transmission lines in the foothills of the Sierra Nevada Mountains.
The team’s vegetation management work is key in forested El Dorado County and has been ongoing for several years. There are plans to expand that work in 2019 further west through the Sierras, an area that is near homes, vineyards, wineries and fruit orchards.
The most recent work began in October after SMUD met with property owners about reducing wildfire risk on their properties. So far, more than 60 acres have been cleared and another 30 acres have been added as adjacent land owners have seen the benefits and requested vegetation management work on their own properties in order to reduce fire risk.
Those land owners are not direct SMUD customers – they are Pacific Gas and Electric customers – but the landowners have SMUD 230-kV electric transmission that cross their property, Eric Brown, SMUD’s vegetation management program manager, said.
Since 2016, SMUD has cleared “several hundred acres” in its Upper American River Project (UARP) hydroelectric project area, Brown said.
Every 36 months, SMUD assesses every area in its distribution service territory with overhead lines on poles and then performs a mid-cycle patrol every 18 months to ensure all trees near lines are in compliance with state regulations.
A key tool in SMUD’s vegetation management operations is what Brown calls “a remote sensing suite,” comprising Light Detection and Ranging (LiDAR) technology, Ortho Imagery, and hyperspectral imagery.
SMUD uses LiDAR to create a three-dimensional model of trees near its towers, poles, lines and other assets. LiDAR creates “exceptionally accurate” measurements in the form of three dimensional images by bouncing laser pulses off of objects to create a map the way submarines or bats use reflected sound waves to navigate. “There is no more accurate tool than LiDAR to measure distances,” Brown said.
Hyperspectral and Ortho imaging is collected and processed through analytic data across the electromagnetic spectrum and can even identify chlorophyll levels in plants, which can lead to early detection of trees in decline. Hyperspectral imaging can yield more accurate and timely information. A tree could look “healthy” to a boots-on-the-ground inspection, but could be dead three months later, Brown said. He said that using these high tech tools “improves our reliability and safety.”
SMUD deploys its LiDAR and hyperspectral imaging tools using fixed wing aircraft or helicopters.
SMUD has been using LiDAR for “quite some time,” Brown said. Traditionally LiDAR has been used on transmission systems and less frequently on distribution systems, but SMUD is expanding its use to its distribution network because of the technology’s greater accuracy.
“This technology saves us time, effort and money in helping us quickly determine which trees need to be removed or pruned, and which can be left alone,” Frankie McDermott, SMUD’s chief energy delivery officer, said in a statement. “Our goal is to provide safe and reliable power to communities, and utilizing a comprehensive suite of evaluation techniques does just that, while reducing the risk of wildfire.”