How clean is veg/bio driving??

[Vijay]

With the new North Circ tax on the horizon, I just wondered how clean driving on veg/bio really is? I know a number of us have had an MOT inspector wonder if their exhaust testers are working properly with such low figures, but any idea how that compares to the new ULEZ requirements?

Vihay

[nigelb]

The issue here is not the emissions now on you current choice of fuel but the level of CO2 stated by the manufacturer.

[Vijay]

does running bio/veg not have a direct influence on the levels of CO2 though?

[dgs]

does running bio/veg not have a direct influence on the levels of CO2 though?

Indeed it does, in fact a 76.4% decrease  over fossil fuels, taking everything into consideration.

[nigelb]

My understanding...probably wrong but, the CO2 out is equivalent to the CO2 absorbed by the growing plant. Nitrous Oxide levels can be elavated.

[Keef]

How far you want to take it.
By running used veg I can save the emissions for the journey to work a few days a month which were just to earn the fuel money to cover the other days. etc etc 

[countrypaul]

does running bio/veg not have a direct influence on the levels of CO2 though?

Indeed it does, in fact a 76.4% decrease  over fossil fuels, taking everything into consideration.

Dave,

Where do you get that figure from? I would expect the CO2 levels to be very similar to fossil fuel levels, I would certainly expect CO levels to be much smaller.

The mpg from Bio/veg is normally slightly lower than dino but given bio & veg are slightly less dense slightly more of each might be expected to be used. In the case of bio and veg is is already partially oxidised (has ester groupings present) so not all of it is carbon/hydrogen so that might also contibute to more being needed for a given mile. The total amount of carbon in 1KG of each  (dino vs bio/veg) is certainly not different by a factor of 4 so expecting bio/veg to produce 76.4% less CO2 appears optimistic.

[dgs]

If we assume all the CO2 is re-absorbed into the plant for growth then the net result would be zero. However there is a carbon footprint simply because of all the fossil fuels used in transport etc etc so net result is the 76.4% reduction.

I will try to find the article I read years ago, but the 76.4 stuck in my head.

[dgs]

How does biodiesel reduce CO2?
The U.S. government considers biodiesel to be carbon-neutral because the plants that are the sources of the feedstocks for making biodiesel, such as soybeans and palm oil trees, absorb carbon dioxide (CO2) as they grow. The absorption of CO2 by these plants offsets the CO2 that forms while making and burning biodiesel.

Biodiesel and the environment - U.S. Energy Information ... - EIAhttps://www.eia.gov › energyexplained › biofuels › biodie...
Search for: How does biodiesel reduce CO2?
Does biodiesel emit less CO2?
As a result, biodiesel produces 78% less CO2 than diesel fuel. Biodiesel produces 2661 grams of CO2 per gallon, compared to 12,360 grams per gallon for petroleum diesel fuel.

[Vijay]

First clash of heads with TFL today. Gave them a call to ask about exemption as I run on biodiesel. I didn't expect the person to know anything about bio and her first reply was bio makes no difference to CO2. So I asked her why they themselves claim that running a B20 mix in their own vehicles reduces their CO2 level by 10%, so why doesn't my B100 make a difference.

She then asked for a letter from the vehicle manufacture that it was made to run on bio. I explained that it's a diesel car that CAN run on bio and she lost that battle. She then asked for a letter of conformity. I asked her what that was and where do I get it. She said she didn't know but I had to get it. After a bit of back and forth, she went away to ask someone and they will get back to me in 10 days.

I don't think I'll get anywhere with it, as I don't think TFL has any real interest in clean air, it's a tax fund IMO and that's all they care about................but I'll enjoy the argument with them lol