Car CO2 emissions: How can you reduce your footprint?

The accumulation of greenhouse gases in the atmosphere is one of the main causes of global warming. Transport, and cars in particular, is one of the main sources of greenhouse gas emissions in the UK. It is important to know the carbon footprint of your vehicle to reduce its impact on the environment. In this article we’ll look in detail at the CO2 emissions of cars, how to check car emissions, and what to do if a car fails the MOT on emissions.

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Car emissions: What are they and how do you calculate them?

The carbon footprint is an indicator that measures the amount of carbon dioxide (CO2) in the atmosphere due to an activity. The average Brit emits around 7.01 tonnes of CO2eq into the atmosphere per year. Around 1.6 tonnes, or 23% are linked to transport.

Figures published by the Department for Transport revealed that in 2018, 808 billion passenger kilometres were travelled across the UK. Of those, 83% were made in a car, van or taxi, highlighting our dependence on these types of vehicles. And as more proof that Brits rely on their cars, data published by the RAC Foundation shows that in 2019, 61% of all trips made were done so in a car. While the average number of miles per car has fallen from 9,200 in 2002 to 7,400 in 2019, this can be attributed to the fact there are more cars per household. In total, there are 32 million cars registered in the UK.

With people moving further out of cities in search of cheaper housing and more space, there is a strong dependency on cars for both short trips and longer commutes to work. All these trips require the burning of fuel and therefore produce greenhouse gases, which play an important role in increasing climate change and air pollution.

In general, the lighter a car is, the less energy it needs to run. The type of energy used to run the vehicle is also an important consideration. However, calculating the carbon footprint of a car is not so simple and it is not only reduced to the gallons of petrol consumed.

Actually you have to take into account:

1. Emissions related to the previous production of car fuel;
2. Emissions related to fuel combustion when necessary;
3. Emissions related to the materials used in the manufacture of the vehicle.

Therefore, regardless of the type of model, the carbon footprint of a car is never zero, not even in the case of an electric car.

Vehicle emissions: Electric, petrol and hybrid cars

The long term target for the UK governement is for most, if not all, drivers to purchase electric cars. As part of that process, it intends to ban the sale of diesel and petrol cars by 2030. As that date is still at least one ‘car purchase cycle’ away, we’ll now look more in detail at what are the CO2 emissions for your car.

How do CO2 emissions affect car tax? Car tax is one of the costs you will need to budget for over the course of the year. How much you pay for Vehicle Excise Duty (VED) – also known as vehicle tax, car tax or road tax - depends on a number of factors including engine size, or fuel type and carbon dioxide (CO2 emissions). In the most basic terms, the lower the emissions, the lower car tax you'll pay.

The carbon footprint of the electric car

Most of the CO2 emitted by an electric car during its life cycle comes from the production process, when it has not even traveled a single mile. This is due to the lithium-ion battery that is responsible for almost half of the CO2 emitted during its manufacture.

However, the electric car pollutes considerably less than any other type of vehicle throughout its life, as long as the battery does not have to be changed.

The carbon footprint of the hybrid car

Hybrid cars are vehicles that use two different sources of energy to get around. They combine an electric motor and a combustion engine (diesel or petrol): the electric motor starts the car and makes it run until it reaches a certain speed, then the combustion engine takes over.

By combining an electric motor and a combustion engine, they adapt to the use of the vehicle and thus avoid excessive fuel consumption. They have the advantage of using the fuel distribution network from time to time, while emitting less CO2.

The hybrid car is, therefore, a means of transition towards more sustainable cars and independent of fossil fuels.

The carbon footprint of the petrol car

Petrol and diesel cars are known to be big contributors to greenhouse gas emissions, which is why so much work is being done to eventually take them off the roads altogether. The average CO2 emissions per car is around 4 tonnes per year. That is not the only concerning issue however.

Petrol and diesel care produce methane and nitrous oxide from the tailpipe and hydrofluorocarbon emissions from leaking air conditioners. The emissions of these gases are small in comparison to CO2 but the impact of these emissions can be important because they have a higher global warming potential.

Where can I check my car emissions?If you look in your V5C registration certificate - or vehicle logbook - for your car, the emissions rating is listed there.You can also find the fuel consumption and use the vehicle emissions checker for a new or used car on the government certificate agency website.

Travel in a more sustainable way

Travelling responsibly means choosing the mode of transport that best suits your needs from the range of options available (on foot, by bike, by public transport, by train, by carpooling, etc.).

Opt for a more environmentally-friendly car

If you cannot do without a car, it is important to choose the right vehicle when buying it, optimise its use and maintain it regularly. These actions are essential to limit the impact of your car's carbon emissions on the environment.

• Choosing the right vehicle at the time of purchase: the amount of CO2 produced by a car is proportional to its energy consumption. That is why it is also important to think about your needs before buying a vehicle and, if possible, choose one that consumes little.
• Take care of your vehicle and perform regular maintenance: each vehicle is sold with a maintenance booklet detailing the correct instructions to follow to maintain your vehicle properly. A poorly maintained car can lead to a 10% increase in fuel consumption. Thus, maintaining your vehicle can significantly reduce your energy consumption and save fuel.

What happens if a car failed MOT on emissions?The car emissions check is a key part of the MOT and can often be the cause of the certificate not being issued. MOT stands for Ministry of Transport - the government department that issues certificates of road-worthiness for all vehicles in the UK. Last year, more than 1.3 million cars in the UK failed the MOT based on the car emissions test. If that happens to you, it means you will be unable to legally operate your vehicle on UK roads.

Alternative solutions to using cars

Although the car is the preferred means of transport for Britons, there are many other more ecological means of transport:

• Walking, using mechanical bicycles or electric bicycles: perfect means of transport for short trips and that allow regular physical activity. Furthermore, using a bicycle instead of a car considerably reduces the carbon footprint.
• Using public transport: a less polluting solution than the car, especially when commuting from home to work.
• Taking the train: in addition to having a lower carbon footprint than the plane or the car, and therefore being energy efficient, this means of transport limits air pollution.

However, if you still have a car trip to take, it is possible to do it with less pollution:

• Green driving: driving at a moderate speed for the first five miles or not abusing the air conditioning are ways to reduce fuel consumption, which also saves money.
• Car sharing: Car sharing not only saves fuel, but also reduces the risk of traffic jams and the impact on the planet.

How to reduce CO2 emissions on my car?

Whatever the official emissions ratings of your car, reducing your CO2 emissions will benefit you and your car. You’ll get better performance, better mileage per gallon and it will help the environment.

Below are some key suggestions to help reduce CO2 emissions for your car:

1. Use better fuel, try premium over regular;
2. Add cleaning agent to the fuel tank now and then;
3. Change the oil;
4. Change the air filter;
5. Check your tyre pressure and keep tyres running at optimum pressure;
6. Turn off your air conditioning when you can;
7. Remove roof racks unless necessary;
8. Don’t sit with the engine running, switch off when you can;
9. Drive with consideration, change gears quickly, and don’t accelerate too hard.

• How to reduce car emissions for MOT?
• Check the oil on a regular basis;
• Get your car serviced;
• Deal quickly with any issues your car may have, especially repairing the exhaust.

The green cars of the future

Carmakers and automotive-tech companies are already working on ways to transform cars and the driving experience in a new, greener world. These are just some of the innovative cars they are working on:

Hydrogen and the development of electric vehicles

A hydrogen-powered car is a vehicle with an electric motor, in turn powered by electricity produced on board by a hydrogen fuel cell. In the cell, hydrogen comes into contact with oxygen in the air to produce water. This chemical reaction produces heat and electricity, which allows the car to move forward. The hydrogen car has the advantage of not making any noise and not producing any polluting or toxic emissions.

Hydrogen is still in the experimentation phase. Technologies associated with hydrogen are still very expensive and, therefore, not very accessible. However, within a few years, hydrogen could be used as fuel for electric vehicles equipped with fuel cells.

Ever greener biofuels

Intended to replace oil in vehicles, advanced biofuels, known as "second generation" (2G), are new fuels obtained from biomass. Of vegetable or animal origin, they use, for example, agricultural, forestry or organic residues. In fact, the CO2 emitted during the combustion of a biofuel is previously compensated by the plants during their growth. They offset greenhouse gas emissions, unlike fossil fuels, and improve air quality.

Smart electric cars

By limiting pollution in cities, smart electric vehicles are associated with the mobility of the future. Autonomous and connected, they adapt to our lifestyle while meeting new environmental needs.

However, for them to be a sustainable alternative, the country's energy mix must be taken into account. Electric cars are only a solution when the country's electricity is not produced primarily from fossil fuels like coal.

Discover more practical guides on protecting the environment and fighting global warming.