In the automotive industry, there are many ways to talk about vehicle emissions. Two of the most common ways are tailpipe emissions and lifecycle emissions. In this article, we will break down what these terms mean and the importance of the distinction between them.
What are tailpipe emissions?
Tailpipe emissions are literally just that: anything that leaves the exhaust pipe of a vehicle. Any gas, liquid, or solid that is released by a vehicle during operations is considered an emission – whether it be water, soot and particulate matter, or carbon dioxide.
Different vehicles produce different types of emissions at different concentrations depending on the fuel the vehicle runs on, the efficiency of the engine, and the filter in place.
Both diesel and petrol engines produce a combination of carbon dioxide (CO₂), carbon monoxide (CO), nitrogen oxides (NOx) and other particulates. Petrol typically releases more CO₂ and less NOx, while the inverse is true for diesel. Other fuel types, such as biofuels and synthetic fuels, also release varying concentrations of CO₂, NOx and other substances.
Measuring tailpipe emissions allows manufacturers and policymakers to quantify the volume of gases and particulates a vehicle is likely to produce during its typical operational life. It also allows policymakers and citizens to measure the impact of vehicles on measurements like air quality, particularly in dense urban areas with lots of vehicles.
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What are lifecycle emissions?
What tailpipe emissions do not consider are the other emissions associated with the production and disposal of a vehicle across its full lifetime.
This is where lifecycle emissions come into play. This concept refers to the total emissions that are produced across the whole lifecycle of a car, from the sourcing of raw materials, through to the disposal or recycling of the vehicle at the end of its life.
Whereas tailpipe emissions are relatively straightforward to measure – typically through standardized vehicle testing and regulatory checks – calculating lifecycle emissions requires a much broader view of the entire automotive supply chain, including energy production and distribution.
Lifecycle emissions cover all emissions from the sourcing of materials to the disposal of the vehicle
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Why is this terminology important?
The automotive industry is in the midst of an unprecedented period of change. As our understanding of the climate and the impact of human activity has grown, there has been a significant push toward decarbonization.
Across governments, industries, and public opinion, there has been a shift toward taking greater responsibility for our collective environmental impact. Within this context, the automotive industry has begun taking steps to reduce emissions and transition toward more sustainable fuels.
As part of this shift, there has been a strong focus on emissions – particularly those that come out of a vehicle’s tailpipe. Before the rapid growth of battery electric vehicles (BEVs), focusing on tailpipe emissions made sense, as these emissions were consistent across most vehicle types.
However, the rise of BEVs has now caused a significant rift between tailpipe emissions and lifecycle emissions. That is because, while these vehicles do not produce any tailpipe emissions, they do require considerably more carbon-intensive processes and materials to produce than a traditional vehicle. Further, they also depend on electricity grids, which typically depend on hydrocarbon power stations that emit carbon themselves.
So, while a BEV’s tailpipe emissions may be zero, there are many situations where the lifecycle emissions of such a vehicle will be comparable – if not greater – than an efficient combustion and hybrid vehicle.
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A nuanced approach to emissions
Because of this broader picture, there is a growing need to move beyond a narrow focus on tailpipe emissions and instead consider the total emissions produced across a vehicle’s full life cycle. This approach provides a more complete understanding of the automotive industry’s overall carbon footprint, and the necessary direction of travel to improve sustainability for the future.
At Horse Powertrain, we are taking a multi-pronged, technologically neutral approach to decarbonization. We develop high-efficiency hybrid and combustion powertrains, including engines designed to run on a range of low-carbon combustion fuels, such as biofuels and hydrogen.
We’re committed to designing the engines of the future, developing technologies that reduce emissions across the lifecycle of the vehicle. Learn more about them here.
