Frequently Asked Questions (FAQ)

What is CO2?

CO2 or carbon dioxide is a naturally occurring gas that is generated when fuel and other carbon based material is burnt. CO2 is also released by us breathing and other natural occurring biological and geological processes. Our atmosphere is currently made up of 0.06% of CO2, 20.9% oxygen, 78% Nitrogen and the remaining percentage is made up of various other gases.

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What is the financial cost?

The financial cost calculated is showing you mow much it is estimated the social cost of carbon is likely to be. This is currently at £75 per tonne. The full report can be found on HM Treasury site. The Treasury is the United Kingdom's economics and finance ministry.

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Why should I care?

Scientists believe that CO2 is a major contributor to a phenomenon called 'global warming'. Global warming put simply is the gradual increase of world wide temperatures over a sustained period of time. The impact of global warming is yet to be fully understood, but many believe that sea levels will rise (due to the polar ice caps melting) and our local weather will gradually become more extreme. This will result in higher summer temperatures, warmer winters, flooding and other extreme conditions. Only time will tell if these predictions are correct, however it is important that we all do our best to minimise our impact to the environment and CO2 levels. For a more in-depth look at global warming please see Wikipedia.

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What can I do?

After you calculate your likely carbon emission (or carbon footprint) for your journey there is a personalised list of suggestions on how you can minimise your impact by making very small changes. Alternatively bus and rail can offer a realistic alternative to your journey by car.

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What is biodiesel?

Biodiesel is a renewable fuel that is produced from the oil of crops including oilseed rape, sunflowers and soybeans, as well as from waste cooking oils. Diesel is sold as EN 590, which can contain a blend of 5% biodiesel and 95% ultra-low sulphur diesel. Biodiesel benefits the environment as follows:

  • Because the crops used to make biodiesel take in carbon dioxide when they grow, biodiesel is considered a renewable fuel. It gives a 60% reduction in CO2 well to wheel.
  • Because it is highly biodegradable, biodiesel does not accumulate and pollute soil and waterways if it is spilt.

One small negative is that oxides of nitrogen, a smog-forming gas, are slightly higher in biodiesel than with ultra-low sulphur diesel.

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What is bioethanol?

Like biodiesel, bioethanol is a liquid bio fuel. It is made from starch plants (like corn, wheat and cassava), sugar plants (beet and cane) and sometimes cellulose plants (trees). It is produced first by fermentation, followed by distillation and finally dehydration. It is generally accepted that on a well to wheel basis, bioethanol gives a 70% carbon dioxide reduction versus petrol.

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What is LPG?

A blend of propane and butane, Liquid Petroleum Gas (LPG) is produced either as a by-product of oil-refining, or from natural gas (methane) fields. As an alternative fuel it is most suited to use in cars and light vans, rather than heavy vehicles. Performance-wise, LPG vehicles drive just like petrol vehicles and are subject to the same maintenance schedules. It is generally accepted that LPG gives a 10-15% carbon dioxide reduction in comparison to petrol and is on a par with diesel. LPG also delivers 80% lower nitrous oxide emissions than diesel, along with zero particulate emissions. Significant additional reductions can be achieved if the LPG system is fully integrated at manufacture rather than through conversion.

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How accurate is this site?

The raw CO2 figures are taken from the VCA Car Fuel Data database site. This data comes from the manufacturer's published CO2 ratings for their car. The figure is the average amount of grams of CO2 generated for every kilometre driven. Various factors will increase or decrease this. Some of the larger factors are listed on the calculation page. So, is the site accurate? The answer is yes, as much as the site can be, but if you were to measure the CO2 you produced on your journey, would it be the same as the number generated here? Probably not, but it would be close.

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What are the advanced options?

The advanced options calculate your carbon footprint based on more real world factors and conditions. For example if most of your journey is done on high speed motorways, then that is taken into account. Similarly if you have converted your car to run on bioethonal then your net contribution to carbon emissions is a lot lower than running on straight petrol. The idea is to personalise the information, rather than provide you with sweeping generalisations.

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Further questions?

If this FAQ section has not been able to answer your problem, or you have any further query regarding the web site then please send us an email

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