2. Description of Lines 101, 132A, and 147, and
Pressure Reductions

Located along the San Francisco Peninsula, Line 101 runs 34 miles from Milpitas Terminal in Santa Clara County to the San Francisco Gas Load Center in San Francisco. Gas coming into Milpitas Terminal supplies the vast majority of customers along the San Francisco Peninsula. Line 101 approximately follows the alignment of Highways 237 and 101. At the Lomita Park Meter Station, located across the freeway from the San Francisco Airport, the pressure on Line 101 is reduced as the gas supply moves toward San Francisco.

Line 132A is a 1.5 mile cross-tie that connects Line 101 at mile point 9.78 to Lines 109 and 132 in the Mountain View area. Line 147 is a 3.8 mile cross-tie that connects Line 101 at mile point 21.54 to Lines 109 and 132.

Along the routes of Lines 101, 132A, and 147, other pipelines tap off of these lines and supply gas to individual customers, distribution feeder mains, distribution regulating stations, or are otherwise required for pipeline operations. These lines are referred to as "shorts," and each of the three lines has numerous appurtenant shorts. Pacific Gas and Electric Company (PG&E) explained that Line 101 has 132 shorts, Line 132A has 9 shorts, and Line 147 has 15 shorts. PG&E is also seeking Commission authorization to increase the maximum operating pressure in the shorts associated with each of the three lines to 365 pounds per square inch gauge (psig).

On September 13, 2010, the Commission's Executive Director ordered PG&E to reduce the operating pressure on Line 132 to 20% below the operating pressure at the time of the San Bruno rupture. Because PG&E had already reduced the operating pressure of Line 132 by 10%, in response to Executive Director's order, PG&E reduced the operating pressure of Line 132 an additional 10% to 300 psig. At the same time, PG&E voluntarily reduced the operating pressure on Peninsula transmission Lines 101 and 109, and associated cross-ties, including Lines 132A and 147, to 300 psig. On September 24, 2010, the Commission issued Resolution L-403 ratifying the Executive Director's order and requiring that PG&E retain that lower pressure level on Line 132 until such time as the Commission allows PG&E to increase the pressure on Line 132.

In its supporting information, PG&E stated that it needs to return Lines 101, 132A, and 147 to normal operating pressure to avoid potential curtailments this winter to core customers in San Francisco and all noncore customers on the Peninsula.