Gas vs propane

Propane and Natural Gas Appliances

When purchasing gas catering appliances it is absolutely essential that you select a unit that is configured for the type of gas fuel supply to your business. Catering Appliance Superstore stocks a wide range of gas appliances such as gas cookers, gas hobs, and gas fryers. In many cases, the same model is available in both a natural gas or a propane gas variant. Although it is usually very clear which type of gas supply you have, and which a particular appliance runs on, it can be helpful to understand the difference between natural gas, propane, butane, and LPG.


What is the difference between types of gas?

All types of commercially available fuel gases are fossil fuels, formed from compressed organic matter over millions of years.

Natural gas is mainly methane, with some ethane and propane as well as impurities such as carbon dioxide, hydrogen sulfide and nitrogen. In its extracted form it is odorless and colorless, but before reaching your property the gas is deliberately odorised with smelly mercaptan compounds to improve safety and leak detection.

Propane is actually a byproduct of natural gas processing. Natural gas is cleaned before introduction to the mains gas supply, and byproducts like propane are separated out for use elsewhere. Propane is also extracted during petroleum refining.

Butane is another fuel gas that is a product of both natural gas refining and petroleum refining. In the UK it is relatively rare for commercial catering appliances to be set up to use butane gas - typically it is seen in the UK only as a bottled gas for camping stoves and other mobile catering appliances, because these may be taken overseas where butane is more common and propane refills are hard to come by.

LPG, or liquid petroleum gas, is just a variable blend of the hydrocarbon gases extracted in natural gas and petroleum refining, such as propane, butane, ethane, and pentane. In fact, although we have listed propane and butane gas above as fuel types, commercially available propane and butane are always a blend of the named gas and other hydrocarbons - bought in the UK other than for scientific use, they are always a form of LPG. Appliances that state they run on propane mean they run on propane LPG.


What are the pros and cons of each type?

Both natural gas and LPG gases are cleaner fossil fuels than any other, producing only half the carbon dioxide emissions of oil and a third those of coal. In terms of cooking performance, there is also negligible difference between the two types, so you don't need to worry about that side of things.

Butane LPG is not commercially available in the UK on the scale required for running a commercial catering operation. It does not perform well stored in cold temperatures (it can freeze more easily than propane), and is only really sold in small canisters for use on the continent or in warmer weather, for example with barbecues and camping stoves.

Propane LPG and natural gas are different in terms of energy efficiency, cost, risk factors and logistical factors such as storage and delivery.


Energy efficiency and cost comparison of natural gas vs propane LPG

These are closely related - natural gas tends to be significantly cheaper in the UK, but propane LPG provides more cooking or heating energy per unit of volume. The two are also measured and priced differently, propane LPG being delivered in compressed liquid form (litres or gallons) and natural gas being delivered in gas form, measured in cubic feet or cubic meters, and priced in kilowatt hours (kWh), so making a comparison using pricing figures from suppliers is complex. The following steps can help you compare pricing easily.

1.) Convert the per litre cost of propane LPG to a cubic metre price. If propane LPG were an unpressurised liquid then 1000 litres would be equal to 1 cubic metre, but since it is a gas pressurised into liquid form, just 3.85 litres of propane LPG expands to 1 cubic metre of gas at the density it is used in cooking and heating appliances. Multiply the litre cost by 3.85 to get a per cubic metre figure.

Example: Propane LPG @ £0.45 per litre x 3.85 = £1.73 per cubic metre.

2.) Convert kWh price to a price per cubic metre. Prices for natural gas in the UK are stated in kilowatt hours (kWh), which is how much energy a 1 kilowatt appliance would use in an hour (or a half a kilowatt appliance would use in two hours). The equation to convert is complex and involves assessment of the calorific value of natural gas, but all you need to know is that 11.06 kWh is equivalent to 1 cubic metre of the stuff. Multiply the kWh price by 11.06 to get a per cubic metre figure.

Example: Natural gas @ £0.04 per kWh x 11.06 = £0.44p per cubic metre.

Based on these figures (consistent with industry prices at time of writing in 2014), propane LPG is about 4 times as expensive per cubic metre as natural gas, although this will of course vary slightly depending on the pricing of suppliers. Next we need to compare the efficiency of the two fuel types.

As a rough guide, natural gas delivers just over 35,000 BTUs (British Thermal Units) of heating energy per cubic metre, whereas propane LPG in the same volume (gas form) provides about 80,000 BTUs. This means that propane LPG contains about 2.2 times more energy potential, so less propane is needed to achieve the same amount of cooking or heating.

Because propane LPG is 2.2 times as efficient as natural gas, the cost figure needs to be adjusted. A fuel product that is 4 times the price but does 2.2 times the work for the same volume could be considered to be only 1.7 times the overall price. In summary, propane LPG is just under twice as expensive in achieving the same results as natural gas, based on gas pricing in the UK at time of writing (July 2014).


Risk factors

Both types of gas need to be treated with the same high level of respect and should be handled with caution. Accidents involving gas where proper safeguards have not been followed are rarely anything other than serious. Ensure you have accessible shut off valves and in a kitchen environment shut off gas at the valve when appliances are not in use. Always contact the National Gas Emergency line on 0800 111 999 if you suspect a leak, open all doors and windows to aerate the property, and stay well away until a professional has advised you it is safe to return.

Both natural gas and propane LPG are heavier than air, meaning that if there is a leak in a still air environment (indoors) the gas will tend to collect at low level rather than dissipate. Propane is the heavier of the two which means it is even more likely to collect at ground level rather than dissipate. Once either gas is concentrated enough, it can very easily ignite, or cause poisoning (although both gasses are easily detectable by odour).


Logistical factors

Regardless of any differences in the properties or costs of natural gas vs propane LPG, you may have little option. Although natural gas is by far the most widely-used heating fuel in the UK, and is the cheapest option, not all homes are on the gas network. Propane LPG is far less commonly used, but where it is this is often because of the isolated location of the property - running a natural gas line out to some rural properties is simply not cost effective.

Of course, you can always opt for LPG supply even if you are on the natural gas mains network, but at current fuel prices and factoring in the cost of conversion, this is not recommended. Conversion costs are also a reason to stick with LPG even if you have access to a mains gasline - don't forget you will need to replace or refit all of your gas appliances.

Unfortunately, there are fewer suppliers of tanker delivered propane LPG then there are energy companies who can sell natural gas through the mains network, so choice can be more limited when shopping around for propane LPG.


How can I tell what supply I have?

The biggest clue to determining whether you have propane LPG is the presence of large, cylindrical gas tanks. In the UK, if your gas comes delivered to these tanks by lorry, you are a user of propane LPG. If you get a gas bill from one of the energy suppliers with units measured in kWh, you are a natural gas user.


What happens if I get it wrong?

Natural gas operates at a lower pressure to propane LPG, and therefore the nozzles that control the flow of gas in any appliance need to be larger to allow enough gas out to perform the cooking or heating task in hand. Connecting higher pressure propane LPG to a natural gas appliance will result in a dangerously large and unweildy flame that can damage the appliance itself, and cause a danger to users and a higher risk of fire.

Conversely, if natural gas is connected to a propane LPG appliance, the lower pressure will result in very low flames or even none at all. This can be a risk in itself, as flames that go out when the gas is still connected can cause gas to leak into your property and build up to dangerous levels.


How can I make sure I purchase the right type of unit?

Catering Appliance Superstore will always try to clearly describe gas products in terms of being a natural gas or propane gas appliance (or butane gas appliance in some rare cases). Many of the product codes will end with either an N for natural gas or a P for propane LPG. The product descriptions will also detail the type of , and where the model is available in both types, there will often be a dropdown box within the product description itself to select between the natural gas and LPG variants.

For an example, please see the Lincat OG7002/N and the OG7002/P.

If you see any products at all that are not clearly described either way, chances are this is a natural gas appliance. Nevertheless we urge you to point out any products where there is a lack of clarity so we can advise you of the correct model, and update the product description.