LPG and the environment
LPG is often advertised as a clean alternative. What is true about that, and where are the limits?
CO2
Burning LPG produces somewhat less CO2 per kilometre than petrol, because propane and butane contain less carbon per unit of energy. The difference is in the range of about ten percent. That is an advantage but not a breakthrough. LPG is a fossil fuel.
Nitrogen oxides and particulates
On air quality LPG does well: it produces far less soot and fine particulate matter than diesel engines, and nitrogen oxide emissions are usually lower than those of diesel vehicles. Compared with modern petrol cars with a particulate filter the difference is smaller.
Comparison at a glance
| Drive | CO2 | Nitrogen oxides | Particulates |
|---|---|---|---|
| Petrol | reference | medium | low to medium |
| Diesel | lower than petrol | higher, depends on exhaust treatment | low with a particulate filter |
| LPG | somewhat lower than petrol | low | very low |
| Hybrid | lower | like combustion engines | like combustion engines |
| Electric | no exhaust on site, overall balance depends on the power mix | none | only tyre and brake wear |
The table shows tendencies. Actual values depend on the vehicle, year and driving style.
An honest assessment
- For the owner of a petrol car, LPG is an immediately available way to cut costs and emissions somewhat without changing the car.
- For climate goals, that alone is not enough. An electric car running on green electricity, or a very economical car, does better in the long run.
- Anyone who keeps driving an existing car avoids the emissions of building a new one. That belongs in the calculation.
- LPG is available as a by-product of oil and gas production, but it does not become climate neutral.
For costs read LPG, petrol or diesel; for the technology What is LPG?