California wildfires make underground utilities an infrastructure priority

Despite years of declaring that conversion of high-voltage, long-distance electrical transmission lines to underground installation was cost prohibitive, Pacific Gas & Electric (PG&E) has announced plans to spend $20 billion over 10 years to bury 10,000 miles of power lines in wildfire-prone areas of California.

The move comes after PG&E filed a preliminary report with the California Utilities Commission noting that the Dixie Fire, which so far has decimated 460,000 acres in Northern California, may have been ignited by a blown fuse on one of its utility poles. The utility company has been linked to multiple fires in California and pleaded guilty last year to 84 counts of involuntary manslaughter in connection with the Camp Fire. 

According to Samuel Ariaratnam, a nationally recognized expert in trenchless technology and a professor and Beavers-Ames Chair in heavy construction at Arizona State University, utility companies are beginning to move their power lines underground, but none have contemplated a project on the scale of the PG&E announcement.

“This action taken by PG&E, while motivated by tragic circumstances, highlights the importance of adopting advanced new technologies despite the initial expense,” said Ariaratnam. “Over time, those upfront expenses will pay dividends in diminished maintenance, repair and replacement costs. Most importantly, it will save communities and lives, not only from wildfires, but from other catastrophic events like ice storms, hurricanes and tornados.” 

Ariaratnam, who has worked at a national level to develop good practices for installing underground utilities using horizontal directional drilling (HDD), answered questions about what these technological breakthroughs mean for public safety, protecting the power grid and minimizing the effects of climate change.

Question: How significant for the utility industry is this move by PG&E? 

Answer: Moving their electrical lines underground is a prudent move by PG&E in terms of minimizing outages and related disruptions often associated with aboveground lines. Utility contractors will benefit from this tremendous project but will likely face staffing issues. Thus, it is important to attract people into the heavy construction industry both at the skilled trades and college graduate levels.

Q: How rapidly do you expect other states with wildfire vulnerabilities to adopt similar conversion plans? Is this a subject of discussion among professional organizations like the North American Society for Trenchless Technology?

A: I believe that other vulnerable states will look at PG&E’s lead and look to also adopt conversion of aboveground lines to buried as a way of hardening critical infrastructure. 

Some of the key professional organizations that would look at this with much interest include: the Power & Communications Contractors Association; the Distribution Contractors Association; the National Utility Contractors Association; the American Society of Civil Engineers; and the North American Society for Trenchless Technology. 

All of these groups have a vested interest in electrical utility construction involving both traditional open-cut and trenchless methods. I have personally interacted with all of these organizations over the years on various utility initiatives.

Q: Although installing utilities underground is clearly beneficial for areas prone to wildfires, what does this technology mean for municipalities and neighborhoods? 

A: Burying electrical utilities underground removes unsightly power lines in neighborhoods, which has been shown to increase home values. 

Today, if you look at newer subdivisions, they typically have buried electrical lines.  

Additionaly, major benefits to having underground utilities are a reduction in disruptions resulting from inclement-weather events and reduced maintenance costs, which are in the range of three to seven times less expensive than overhead lines, according to a published study by PDi2, a utility consulting company.

Q: How can trenchless technology facilitate the growth in communications industries, especially fiber optics?

A: Trenchless technologies, especially horizontal directional drilling (HDD), are vital to the telecommunications industry. 

One thing that the pandemic showed us, as a majority of people worked or studied remotely, was the lack of broadband networks. Just drive around any city today and you will see HDD rigs installing fiber optic lines. All of the major telecommunication companies (Verizon, AT&T, Sprint, etc.) are rapidly expanding and upgrading their networks. HDD allows this to be done fairly quickly, economically and with minimal disruption to the general public.

Q: Are there other arenas in which trenchless technologies can have an impact on mitigating the effects of climate change? 

A: There have been numerous studies over the years, including several that I conducted, that have shown environmental benefits of using trenchless technologies, especially in the reduction of carbon. Trenchless equipment has been found to emit significantly fewer airborne emissions into the atmosphere compared to equipment used in traditional, open-cut construction. 

Today, we are using HDD for installing conduit to offshore and onshore wind farms as well as solar farms. In 2019 and 2020, several engineers from Orsted, a Danish energy company, came to Tempe to learn more about the capabilities of HDD for mitigating the effects of climate change. Orsted is the world’s largest developer of offshore wind power. They are currently developing offshore wind farms in the New York/New Jersey area. I recently spoke to a contractor engaged in HDD for offshore wind farm applications who is quite excited about this application of the technology.

Installation of geothermal heating/cooling systems is another area where HDD has proven to be beneficial. Geothermal energy harnesses heat derived below the Earth’s surface to generate clean, renewable energy that emits little to no greenhouse gases.

Overall, trenchless technologies provide sustainable practices for construction and rehabilitation of underground infrastructure.

Terry Grant
tvgrant1@asu.edu