PR-08-43 -- PSC Sets Tree-Trimming Standards For Electric Utilities

Contact: Kevin Kelly (573) 751-9300

FOR IMMEDIATE RELEASE -- OCTOBER 2, 2007

Increased electric reliability for consumers the goal of rules 

      JEFFERSON CITY—Today the Missouri Public Service Commission adopted final rules requiring the state’s four investor-owned electric companies to do more extensive tree-trimming and develop detailed vegetation management plans. 

    “These rules adopted today are designed to increase electric service reliability for Missouri consumers,” said PSC Chairman Jeff Davis.  “By putting in place the first industry wide tree-trimming standards for investor-owned electric utilities in Missouri, the Commission is attempting to balance increased service reliability with keeping electric rates low.”

    The vegetation management rules require: specific tree-trimming standards and clearances from power lines; visual inspections of all power lines; specific factors to be considered in determining the extent of vegetation management to be performed; and required customer notice/education programs.  The Commission’s vote was 4-1.

   Vegetation management rules were developed following weather related outages during the summer of 2006 and winter of 2007 as well as in response to customer concerns regarding the reliability of electric service.

    Under the rules, all electric companies must perform visual inspections of their facilities at least once every two years in the urban areas and at least once every three years in rural areas.  Where needed, the company will be required to perform vegetation management in a timely manner.  Vegetation management is to be performed in accordance with American National Standards Institute (ANSI) and National Electric Safety Code Standards.

    Factors to be considered in determining the extent of vegetation management to be performed at a particular site are:

• Rate at which each species of vegetation is likely to grow back.
• Voltage of the energized conductor (power line), with higher voltages requiring larger clearances. 
• The company’s legal rights to access the area where vegetation management is to be performed.

    Under the rules adopted by the Commission, all electric utilities are to file an annual report with the Commission.  That report is to include: expenditures for vegetation management in the preceding year; circuit completion dates and miles trimmed in the preceding year and the vegetation management budget for the current year.  The PSC Staff is to review the vegetation management annual reports for compliance with the provisions of the rule.

     The vegetation management rule also requires each electric company to make a diligent attempt to notify all property owners or occupants that may be affected by planned vegetation management.  They are also required to conduct annual public education programs to inform customers on the importance of vegetation management.

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Case No. EX-2007-0214