News

There's a tiny little thing
That happens on our system
When a person tries to nominate
To an exact position.

Shrinkage is its name,
And rounding is the game;
Depending on the way you go
It may not be the same.

Whatever path you may now take
To move your gas around,
You may end up with slightly more
Since shrinkage has gone down.

But what about those decimal points
That formulas do cause
When multiplying or dividing--
What are the "shrinkage laws"?

This rule applies when entering
Receipt Point quantities:
The right delivered volumes come
By rounding down, you see.

Delivered volumes have the
Opposite effect from this:
Round up the volumes for Receipt Points
And you just can't miss.

So when you figure just which way
You'd rather do the math,
Keep in mind the shrinkage rates
For that specific path.

With the October 1st changes in PG&E's shrinkage rates, California Gas Transmission would like to reiterate the calculations used when delivering gas to the Citygate. Specifically, CGT reminds its customers to round up when calculating receipt volumes from delivered volumes, and to round down when calculating delivered volumes from receipt volumes. The examples below illustrate this rule:

NONCORE TRANSMISSION-LEVEL END-USE CUSTOMERS:

Delivery Point to Receipt Point:

When entering nominations using Delivery Point volumes, the formula to determine Receipt Point volumes works as follows:

Delivery Point volume / (1-x) = Receipt Point volume
(where x equals the decimal equivalent of the transmission shrinkage percentage)

Example: 700 Dth / (1-.0137) = 710 Dth

Rounding in this instance is always up (709.72 Dth becomes 710 Dth).

Receipt Point to Delivery Point:

When entering nominations using Receipt Point volumes, the formula to determine Delivery Point volumes works as follows:

Receipt volume * (1-x) = Delivery volume
(where x equals the decimal equivalent of the transmission shrinkage percentage)

Example: 500 Dth * (1-.0137) = 493 Dth

Rounding in this instance is always down (493.15 Dth becomes 493 Dth).

If you have questions concerning these new shrinkage rates or rounding, please contact your California Gas Transmission Account Services Representative.