LPG, liquefied petroleum gas

Power of gas, convenience of liquid

LPG is a natural by-product from the extraction of natural gas and oil, and from refining crude oil. At room temperature, LPG is gaseous, but it becomes liquid when cooled or pressurised. In liquid form, the gas can be easily transported and stored on-site in tanks of varies sizes, including small cylinders.

LPG is particularly suitable fuel for rural areas that are not connected to the mains gas grid. In these areas it may provide people and businesses with a low-carbon and economic alternative to coal, heating oil, diesel or electricity from the grid.

Similar to natural gas from the mains gas grid, LPG is a flexible source of energy and has a wide variety of uses including space and water heating, cooking and power. It is also increasingly applied in transport. In combination with energy efficient conversion technologies such as condensing boilers and micro-CHP systems, further carbon and energy savings can be established.

LPG is considered a cost-competitive alternative to other fossil fuel options in regions where a mains gas grid is not available. LPG is usually more expensive than natural gas from the grid.

The economics of LPG depend on several factors, including the volume that is used. Big consumers can decide to install an LPG tank at their location. This will require an initial investment. Based on the actual usage, the tank must be refilled on a regular basis. Special equipped trucks must then access the location, which could pose a problem for some locations. Tailor made solutions with smaller trucks are available, but comes at a higher cost. An alternative solution might be to use LPG cylinders, which are available at petrol stations.

General Info

What is it?

Liquid Petroleum Gas (LPG) is a mixture of gases (propane and butane) extracted from natural gas and oil and stored and transported as liquid under pressure.

What are the benefits?

Low Carbon: LPG is a low carbon alternative compared to fossil alternatives such as coal and heating oil. CO2-emissions from LPG are respectively 15% to 20% lower.

Efficiency: The energy content of LPG is higher than most fossil alternatives. As a result, LPG can for instance, produce hotter flames, which can result in higher efficiency.

LPG is a natural by-product of oil and natural gas production.

For the extraction, no extra efforts are needed to produce the gas.

Costs: The higher energetic value and efficiency make LPG a cost-competitive fuel in those regions not connected to the gas network.

Flexible: LPG can be stored in cylinders or in special tanks placed by houses, farms, industrial complexes and the like, making it a highly flexible fuel that can be used for cooking, heating as well as power generation. When used in heat pumps, micro-CHP and condensing boilers it can further increase the efficiency of the system. Unlike liquefied natural gas (LNG), LPG does not require cooling to be liquefied.

How does it work?

LPG is a natural by-product that occurs during the extraction of natural gas and oil or from refining crude oil. At room temperature, LPG is gaseous, but with either modest cooling or pressure it becomes liquid. In liquid form it is easier to store and transport. To keep it liquid, LPG is mostly stored in steel, aluminium or composite containers where its pressure and temperature can be kept constant.

Suitability/applicability

LPG is particularly a suitable fuel for rural areas that are not connected to the mains gas grid. In these areas it may provide people and businesses with a low-carbon and economic alternative to coal, heating oil, diesel or electricity from the grid.

Similar to natural gas from the mains gas grid, LPG is a flexible source of energy and has a wide variety of uses including space and water heating, cooking and power. It is also increasingly applied in transport. In combination with energy efficient conversion technologies such as condensing boilers and micro-CHP systems, further carbon and energy savings can be established.

Sufficient room do needs to be available for the tank. Filling the tanks requires the access for special trucks. This could pose a problem for some remote areas or in those cases where trucks cannot access the tank. Tailor made solutions with smaller trucks are possible, but come at higher cost.

An alternative can be to use portable cylinders. These cylinders weigh up to 5 kg and are sold at petrol stations. This will enable smaller users to use LPG and avoid high costs for refuelling in inaccessible areas.

Detailed Info

Costs, Savings, Earnings

LPG is considered a cost-competitive alternative to other fossil fuel options in regions where a gas network is not available. LPG is usually more expensive than gas from the grid.

Because it is a by-product of oil and gas processing, it is easier to extract and the liquefaction process is less expensive as compared to LNG.

Depending on the volume used, it is decided to place a LPG tank nearby the location. This will require up-front investments costs.

Environmental Impacts

LPG is considered a low-carbon, low-polluting fossil fuel. LPG emits about 20% less CO2 than heating oil and 50% less than coal.

When used as an automotive fuel, LPG emits 15% less CO2, 40% less hydrocarbons and 35% less NOx (mono-nitrogen oxides NO and NO2). However, the energy that is needed to produce, transport and store LPG, should be included as well. This results in more emissions as compared to natural gas delivered by gas networks. LPG is not a renewable fuel.

Efficiency

As LPG is a fuel, its efficiency depends on the efficiency of the technology that converts the fuel into end-uses such as heating or power. There are two relevant points to highlight:

  • In the tank, the LPG is kept at a constant pressure and temperature. Under these circumstances, the LPG is at boiling temperature, producing vapour (gas) that can be used for cooking and heating. To maintain the pressure at a constant level, a regular gas demand is required.
  • As opposed to LNG, boil-off does not occur in LPG tanks and cylinders as they are sealed pressure vessels.

Commercial Maturity

LPG is fully commercial and widely available throughout Europe.

Level of Maintenance

Not applicable

Technical Details

LPG is a mixture of propane (C3H8) and butane (C4H10). The ratio between the components can vary. Depending on this ratio, the technical details below may vary between the given ranges:

Cooking point: between -10C and -420C Melting point: between -1380C and -1880C (Primagaz, 2013) 1,2

Caloric value

93 – 125 MJ/m3 (Alternate Energy Systems, 2013)3

Heating value LHV: 46-48 MJ/kg

HHV: 49-52 MJ/kg

(Staffell, 2011)4

Trade associations

European LPG Association

www.aegpl.eu

World LPG Association

www.worldlpgas.com