Low Carbon or No Carbon?


Does Biodiesel create Carbon Dioxide?

Yes - Biodiesel creates carbon dioxide when it is burnt in diesel engines just like fossil diesel.
Why is biodiesel better for the environment then?

Biodiesel is often referred to as being a carbon neutral fuel, this means that when it is burnt is does not add any new carbon dioxide to the atmosphere, it just recycles what was already there - see how this concept works below:

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The Biodiesel CO2 cycle



The Biodiesel CO2 Cycle

Biodiesel releases only the CO2 that was absorbed by the plants as they were growing and making oil. The result is that when this CO2 is released during combustion of the fuel, no new CO2 is created. The energy to power the vehicle is actually derived from sunlight energy captured, via photosynthesis, when the plants were growing. This is why biodiesel is sustainable, it is powered by the sun!

The result is carbon balance and no increase in CO2 emissions. In reality, a small amount of fossil energy is required to make biodiesel, so the overall balance is about 80% less CO2, rather than 100% less.

Biodiesel is therefore a very Low Carbon fuel rather than a No Carbon fuel, this makes it significantly better than fossil fuels which continually add new CO2 to the atmosphere, driving Global Warming forward.

Biodiesel also burns more completely in diesel engines. This is because of the presence of oxygen in the biodiesel molecules which helps it burn more cleanly. You can see that biodiesel burns more completely by the large reduction in black smoke that diesel engines cause. Black smoke is unburnt fuel, which is in itself very inefficient, but more importantly, black diesel smoke causes widespread urban air pollution and smog.

Unburned black smoke from diesel exhausts is called carbon particulates (or particular matter - PM). These are linked to respiratory diseases and possibly to lung cancer. Biodiesel reduces particulate smoke in vehicle exhausts by up to 60%.