Development of a business case for scheduling utility vegetation management on a preventive vs. corrective maintenance basis – Phase Three

2014 | John W. Goodfellow, BioCompliance Consulting, Inc.

The Utility Arborist Association (UAA) established the need to gain better understanding of how best to determine optimum vegetation maintenance cycle periods and the tradeoffs between the relative costs of preventive vs. corrective maintenance as its top research priority. The TREE Fund’s Utility Arboriculture Research Fund funded a project which addresses this question. The project was funded in two stages. The presentation being proposed will be a final report of findings from both phases of this project.

A quantitative assessment model was developed in the first phase of the investigation, and findings were reported at UAA/ISA Annual Conference in Toronto in 2013. This initial phase of the investigation laid the foundation for a proof of concept assessment and demonstration.

Work on the second phase of the project is expected to be completed in March 2015. This second phase of the project is intended to validate the algorithms that were developed in Phase I. Initial testing is being done using a logical strawman surrogate intended to represent a hybrid virtual vegetation management program. The final step will be to validate the model by completing a pilot demonstration using data available from a participating utility vegetation management program.

Study Results

The TREE Fund’s Utility Arboriculture Research Fund has been supporting research focusing on the question of how to establish a quantitative basis for preventive vegetation maintenance. An initial project (2013) defined important relationships between costs (direct and indirect), performance (safety and reliability) and customer satisfaction from a risk management perspective. It also proposed a suitable analytical method for addressing this question.
BioCompliance Consulting, Inc. has completed a follow-up project that was successful in developing and validating a risk-based model that support informed decisions on the tradeoffs between vegetation maintenance expense and tree-initiated risk to overhead distribution systems. The model is unique in that it includes the cost consequences of outages to end-use customers.
The project also demonstrates that without consideration of the indirect cost impact of tree caused outages on customers, it may be difficult to establish an economic business case for preventive maintenance. The direct cost to a utility of tree-related risk are generally too small as compared to the cost of preventive maintenance, justifying only a “run to failure” corrective maintenance strategy. However, the impact to reliability of such a deferral strategy is recognized as unacceptable from a customer satisfaction standpoint, and is operationally unsustainable.

Findings from this series of projects have been regularly reported to the industry. The principal researcher has made presentations on this body of work on the following occasions:

• Phase I UAA Annual Conference in Toronto 2013
• CEATI webinar, Q1 2015
• ISA Southern Chapter /UAA Conference, March 2015
• ISA Cost of Not Maintaining Trees Symposium, Tampa, March 2015
• UAA Annual Conference, Orlando 2015

Articles discussing portions of this work have appeared in the UAA Newsline and T&D World Magazine.

For more information on this project, contact the researcher via TREE Fund at treefund@treefund.org.