YOUR GUIDE TO PROPANE GENERATORS

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LPG: OVERVIEW and FACTS

About a century ago, when scientists were trying to find a way to store gasoline, which as we know evaporates under normal conditions, they discovered that several gases could be changed into liquids and stored in bottles. The most abundant of those gases was propane. Nowadays, it is bought and sold as liquefied petroleum gas (also referred to as LP-gas or LPG), and is widely used for heating homes and for operating equipment.

A propane generator is actually a set that contains a LPG-fueled engine and an electric generator head mounted together into a single piece of equipment called genset. Technically speaking, propane is a hydrocarbon C3H8. It is a colorless gas, which for practical use is produced as a by-product of both natural gas processing and crude oil refining. Commercial LPG normally also contains butane, propylene (5% maximum) and an odorant. It is a popular choice of fuel because of its very low boiling point of -42 °C. LPG vaporizes as soon as it is released from a pressurized container, so no carburetor or other vaporizing device is required. LPG can be stored as a compressed liquid in steel containers with the sizes ranging from small 5 lbs BBQ cylinders to large 4500 lbs stationary tanks. Large tanks can be installed above ground near the house, as well as underground. When new buy LPG containers be sure they are purged to ensure that there are no water and gas contaminants present.

PROS AND CONS OF PROPANE GENERATORS

LPG gensets range from small portables to large standby systems. Depending on the size, they can power small appliances and tools or an entire home. They are widely used in private homes as a prime power source where grid is not available or as backup power sources when the grid fails. LPG price generally follows crude oil price trends. However LPG has a lower BTU content and lower efficiency than diesel and gasoline: with the same HP of the engine, a LPG powered model will generate 15% less power than a gasoline model, and 30% less than a diesel. Although LPG is normally cheaper than gasoline or diesel, its lower cost per gallon does not completely offset its lower efficiency, which makes it a bit more expensive fuel choice. However, if you plan to use the genset only in an emergency, this does not present a real issue.

When people are buying a standby generator for the home, the fuel type is normally selected based on the fuel already used for the home heating. Therefore LPG standby gensets are most commonly used in residential areas not serviced by the natural gas distribution system. The pipe sizing, construction and layout must comply with NFPA 58 as well as state and local codes.

As for portable gensets, selection of the fuel depends on your application and cost considerations. If you have to frequently move your equipment from place to place, such as on construction sites, dragging a propane cylinder along with the generator may be inconvenient. For such applications diesel and gasoline models with built-in on-board fuel tanks make more sense. However, for an emergency home use, an LPG-fueled portable is a more reliable choice because propane can be stored practically indefinitely and it will not gum up the engine's fuel system. It is also the only type of an easily transportable fuel that can be refilled during a major blackout when gas pumps do not work. And if you have a large propane storage tank, you can hook up your LPG portable device for a long runtime without the need to re-fuel. You may just need to install an additional pressure regulator. A propane genset may also be a good choice to supplement a PV system in off-grid homes. By reliability and price, LPG devices are somewhere in the middle between diesel and gasoline models. Generally, portable propane gensets are cheaper than diesel-fueled devices, but cost some 20 to 50% more than gasoline ones. Typically, they may last longer than gas models and start better in cold weather.

From the environmental standpoint, propane generates less carbon emissions and is more environmentally friendly than other fossil fuels. It is considered generally safe to use- a properly functioning LPG appliance do not produce carbon monoxide or other toxic fumes. However, its fumes are flammable and potentially explosive. Also, some carbon monoxide can still be produced during so-called incomplete combustion of propane. That's why like all other types of gensets, LPG sets should never be used indoor.

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