Imagine with the stroke of a pen that a new law makes your utility responsible for thousands of “new” code infractions and suddenly subject to millions of dollars in potential fines. This is not such a stretch given the Federal Energy Regulatory Commission's (FERC) aggressive position on vegetation management issues and the proposed North American Electric Reliability Council (NERC) reliability standards. So, what are you going to do?

This challenge is a distinct reality for utilities in California. California law requires mandatory clearances between vegetation and overhead electric lines and around designated utility poles. Violations are subject to fines up to US$20,000 per occurrence, per day. How did we get here? The reasons are many and often disputed, but one thing is clear: State regulators have taken a keen interest in utilities' vegetation management practices.

In 1997, the California Public Utilities Commission (CPUC) created the “18-inch rule,” requiring 18 inches of clearance between vegetation and primary conductors at all times. The regulators have set a clear expectation: There must be an obvious separation between tree limbs and power lines.

Pacific Gas & Electric Co. (PG&E; San Francisco, California) has responded accordingly. We tripled our vegetation management budget and worked with our contractors to deploy hundreds of crews. By 1999, even though we were following the industry standard — inspecting and trimming trees on a three- to four-year cycle — we still had violations. Unfortunately, the industry standard equates to inspection of one-third or less of your service area each year, and it allows for 20% of the trees on your system, on average, to actually be in contact with primary conductors at the time of the next pruning. Long story short, we knew we had to make some radical changes.

The California regulations produced a Utility Vegetation Management (UVM) environment like no other in the United States. It required us to think in new ways, in many instances contrary to industry norms. This fresh start has resulted in a project management approach to UVM at PG&E. We have developed a series of processes and practices that has produced a 99.5% compliance rate, significantly reduced outages and improved safety statistics. Intensive planning, precise execution and meticulous quality assurance have brought us the success we enjoy today.

PG&E's Vegetation Management Department is a centralized group of motivated experts. Our staff includes certified arborists, registered professional foresters and certified quality assurance professionals. Many are past or present officers of various industry associations, and we support active membership in organizations such as the Utility Arborist Association, International Society of Arboriculture and Society of American Foresters.

We have developed and created a pre-inspection patrol standard and methodology that is well structured to prescribe the scope of work for any given tree. When you inspect 118,000 line miles and work about two million trees every year, you have to know what you're going to do, when you're going to do it, and verify that it's been done according to the contract and within the budget. Our database and data management is the key technology that allows this level of planning and scheduling.

Our contracted crews perform line clearance tree work in accordance with American National Standards Institute (ANSI) pruning and safety standards and in alignment with the recently published Utility Pruning Best Management Practices (Kempter, International Society of Arboriculture, 2004). To address long-term workload, we use Integrated Vegetation Management (IVM) practices to promote the removal of fast-growing trees and replace them with low-growing species. Our database helps us manage the workload and target priority trees for removal.

We believe that PG&E is unique in the industry in that we have a separate group of people within the Vegetation Management Department who are dedicated to quality assurance. Their work is the cornerstone of our successful UVM program. This group is dedicated to the task of verifying our compliance with regulations and assessing our processes and procedures to help prevent compliance issues rather than correcting them after the fact.

Based on objective measures of safety, reliability and compliance with state regulations, Vegetation Management Department is a true success story. PG&E may have the largest vegetation management program in North America, but we are not just big and we are not just throwing money at a problem at the behest of our regulators. We have embraced vegetation management as a core capability of our organization and a key to our success as an energy-delivery company. As the Northeast blackout demonstrated, an effective vegetation management program is in everyone's best interest. We hope that sharing our experience is a benefit to the industry, and we welcome comments that might make us better at performing this critical function.

Jeffrey Butler is senior vice president of transmission and distribution at Pacific Gas & Electric Co. and a registered professional engineer in California. He graduated in 1979 from California State University, Chico, with a BS degree in electrical and electronic engineering. jdbf@pge.com