What is liquefied petroleum gas (LPG)?

LPG is an energy source used primarily in homes and businesses for heating, powering hot water systems and cooking food. You can also use it to fuel barbecues, cars (known as Autogas) and even forklifts.

It is an odourless, flammable gas produced through crude oil refining and processing natural gas, and is a mixture of propane and butane hydrocarbon gas.¹

There are many benefits of LPG, and people often opt for it because it’s a clean, cost-effective, efficient and portable fuel source compared to other types of gas – even other alternative fuels. While not a renewable energy source and still classed as a fossil fuel, LPG isn’t as damaging as crude oil-derived fuels such as diesel. It might also be used if a home or business wants to use gas appliances but isn’t connected to the natural gas mains pipeline.

LPG produces fewer greenhouse gas emissions than traditional sources of energy but more than a renewable source such as solar. For example, hot water systems produce a lot of carbon dioxide. But, in some cases, using LPG for hot water systems can be a better environmental alternative to electricity, producing up to 15% less greenhouse gas emissions.²

It’s also easy to transport LPG since it’s available for purchase in gas bottles of various sizes.

Propane gas and liquefied petroleum gas are fundamentally the same types of gas, although LPG may contain other carbon fuels such as butane.¹ When pressurised, both propane gas and LPG liquefy and can be used as a source of fuel or heating. Both are commonly stored in gas cylinders or bottles.

There are a few key differences between LPG and natural gas, including their main component, delivery, availability and storage.

The main difference between LPG and natural gas (which can be a mixture of many different types of gas) is how they’re distributed. Natural gas is accessible through pipelines, while LPG is available via cylinders or gas bottles.³ Even though LPG and natural gas are used widely across Australia for similar purposes, they’re also made up of different gases. LPG is essentially propane, while natural gas contains mainly methane.⁴

Where you live in Australia usually determines whether you have access to natural gas. If you require gas as an energy source but can’t access natural gas from the mains supply, you’ll typically need to order LPG.

Keep in mind that while many household appliances can use either LPG or natural gas, gas retailers usually won’t let you use both. In these cases, ensure your appliance is fitted with the right connections for the type of gas you’re using.

There are various sizes of LPG cylinders available, with most households requiring a 45kg bottle at a minimum. The size you’ll require may depend on how you use the gas, 90kg, 190kg and 210kg LPG tanks are also available.

Common household LPG cylinder sizes and their uses are:

• 4kg-9kg: Barbecues, camping stoves and outdoor heating
• 45kg: Standard household use
• 90kg: Large homes or homes with high usage.

Cylinders over 45kg will need to be filled onsite by professionals or exchanged. Smaller cylinders and gas bottles (such as 4kg and 9kg bottles used for barbecues or outdoor heating) can be exchanged.

LPG can have many uses around the home and fuel an array of gas appliances from ovens to heaters. A household’s LPG use may include:

• ovens
• gas stoves and cooktops
• barbecues
• gas hot water systems
• heaters.

There are three main LPG suppliers across Australia, being Elgas, Origin and Supagas. There may also be smaller, local suppliers in your area.

The cost of LPG depends on factors such as delivery fees, rental fees and usage fees, so there’s no single answer for the amount each household will pay.

As well as differing costs between retailers and gas bottle sizes, you may incur:

• Delivery fees. Suppliers may set prices to fill or replace your bottles.
• Rental fees. If you use exchange services, you could be charged a rental fee for the cylinders.
• Usage fees. You’ll usually pay more if you consume higher volumes of LPG. The price of a 90kg gas bottle for your home will be more than a 45kg bottle.

You generally have two options for refilling your liquefied petroleum gas (LPG) cylinders when they are empty. Suppliers can fill the cylinders onsite via an automatic tanker delivery if you have 90kg bottles (or heavier). They can also arrange a gas bottle exchange if you have 45kg bottles, where empty cylinders are replaced with full ones.

Both options can be organised through your supplier and are designed to keep LPG connected to your house. Many households choose to have multiple cylinders installed at one time; you use the other cylinder when one runs out, and the empty one is replaced.

Smaller LPG bottles are usually used for camping, barbecues or small gas heaters. Gas bottles that are 9kg or less can often be replaced or refilled at most service stations.

You’ll usually need to have your liquefied petroleum gas (LPG) bottles delivered by an authorised supplier. If you’re transporting them in a car, the capacity must not exceed 9kg and there can’t be more than two cylinders at a time. This often applies to smaller bottles used for powering appliances such as barbecues.

As most home gas bottles exceed this weight, you’ll need to organise LPG delivery through an authorised supplier.

No, generally, it’s not safe to use an LPG cylinder that’s rusted or damaged in any way. If the LPG cylinder has damage, rust or has been affected by heat, you should discontinue use until professionals can inspect it at a gas tank test station.⁵ If you’re unsure if your LPG cylinder is damaged or need advice, contact your gas retailer for assistance or a replacement gas bottle.

If one of your liquefied petroleum gas (LPG) cylinders is empty, switching to the full one is a straightforward process as your cylinders will either be equipped with a manual or automatic changeover system. With automatic systems, your gas supply will, as the name suggests, automatically switch from the empty cylinder to the full one.

For manual changeover systems, always refer to your supplier for instructions on how to change bottles and the safety steps to follow. Some gas bottles may have an indicator that notifies you (usually by a colour-coded message on the bottle) when it needs to be replaced.

All LPG cylinders should be stored upright and outside in a ventilated location. The cylinders shouldn’t be exposed to excess heat, as this could cause leaks or explosions. Generally, cylinders are installed in a safely designated location near your home and shouldn’t be moved or tampered with without professional guidance.

Any installations must be done in line with your state’s regulations, which is why it should only be done by licensed gasfitters.