Piedmont Energy Systems, Inc.

High Performance, Custom Engineered Systems

Propane-Air Standby Systems:

What is a propane-air standby system?

A propane-air standby system, as offered to industrial and utility natural gas users, is a system that is an alternative source of energy. It is activated in the event a natural gas source is curtailed or shut off completely. Some facilities use oil as a standby system, but oil is not a direct replacement for natural gas because oil requires separate burners, controls and piping. Propane is an ideal standby fuel for natural gas. When mixed with air, propane duplicates the burning characteristics of natural gas, allowing the use of existing burners, controls and piping.

Some of the key components in this type of system are:

Propane Storage Tanks:

(used to store the bulk liquified propane)
Vaporizer:

(used to convert liquid propane to a gas)
Mixer/Blender:

(used to accurately mix the vaporized propane with air)

Standard Detail for a Propane-Air Standby System

Why use a propane-air standby system?

First, a standby system is insurance against any interruption of natural gas supply. Second, a standby system allows industries to take advantage of interruptible rates for gas usage. Many industrial gas consumers are not aware that natural gas contracts that gas companies have are for specific amounts of natural gas for specific lengths of time. These contracts are for residential and industrial customers alike, but when residential users consume more gas than anticipated during unusually long or severe cold periods, industrial users can have their service interrupted. A gas flow interruption can be very costly to industries in terms of damage to equipment, loss of production and even plant shutdowns. Natural gas companies, therefore, encourage the installation of a standby system in the event natural gas service is interrupted. Winter raises the probability of such interruptions, and as an incentive, most gas companies offer an interruptible rate to those with standby systems. This rate is effective throughout the year and is usually significantly lower than the standard non-interruptable rate. With a standby system in place, industries may take in stride the 2-hour notice gas companies customarily give prior to an interruption, and simply switch over to their propane standby system. Given the lower interruptible rate, some plants may amortize a propane-air standby system cost in less than two years.

What is a peak load shaving plant?

A peak load shaving plant is a term used by gas companies to define a facility using a gas blending program. Gas companies' best planned quotas for gas usage cannot allow for unexpected cold spells or broken gas lines. Therefore, to supplement contracted-for gas, gas utilities will use a propane-air mix to duplicate the BTU content of natural gas. This permits a more consistent customer fuel rate and allows utilities to meet peak demand loads.