Clean vehicles require a lifecycle approach to emissions

In future, a vehicle’s CO2 footprint may be calculated from ‘well to tank’ to consider the emissions that arise during manufacturing, fuel production and recharging. By Freddie Holmes

Today, passenger car emissions are judged by how much fuel is used in the vehicle, known as the ‘tank-to-wheel’ lifecycle. But with the onset of vehicles with zero tailpipe emissions, measuring the environmental impact of a vehicle will need to change.

As such, a holistic view of greenhouse gas emissions that takes into account the manufacturing process and other outside CO2 contributions relating to the vehicle could be effective. For electric vehicles (EVs), an assessment of how energy efficient the vehicle is when recharging should also be considered, for example. Jan Mather, Operational Compliance Manager at the UK National Grid, says EVs could potentially “have the biggest impact on electricity demand in the future.”

Tesla Model S
Electric vehicles may have no tailpipe, but emissions do arise elsewhere

Some cities have already employed such a stance on emissions that originate outside of the vehicle; in March 2016, a Tesla Model S that had been imported into Singapore was deemed liable for a US$15,000 surcharge by the Singapore Land Transport Authority (LTA) based on its electrical energy consumption. It came as a surprise when considering that EVs typically receive a clean vehicle tax break, and in Hong Kong—the country in which the car was first registered—the Model S was even exempt from registration tax at the time.

Automakers have also considered how the approach could affect their line up. In 2018, Mazda touted that its SKYACTIV-X gasoline engines could have lower well-to-wheel emissions over its life cycle than an EV, and by 2050, plans to reduce its corporate average well-to-wheel CO2 emissions by 90% compared to 2010 levels.

“We need to take a more holistic approach to all development steps,” said Martin Rothbart, Senior Product Manager Energy and Sustainability, AVL. Speaking during a recent Automotive World webinar, he explained that outside of a vehicle’s fuel tank, emissions also originate from the production of raw materials, manufacturing processes and even recycling. “Rule making and legislation is disconnected—we have rules for well-to-wheel and well-to-tank but without a strong interlink. We believe that in future, in order to reduce overall CO2 in the lifecycle, those regulations will become interconnected.”

Today, passenger cars leverage a range of different powertrain options, with anything from an internal combustion engine (ICE) and various hybrid variants, to battery electric (BEV) and fuel cell (FCEV). All of these propulsion options will continue to coexist in the future, and each technology has different hurdles to overcome. The ICE, for example, faces primary challenges in terms of curbing the CO2 created by burning fossil fuels, along with harmful emissions such as particulate matter. BEVs face the challenge of reducing CO2 generation outside of the vehicle itself, such as during the production of batteries. The primary challenge facing FCEVs relates to refuelling infrastructure, along with clean production of hydrogen.

Daimler hydrogen filling station, Bremen
Hydrogen derived from renewable energy would reduce a fuel cell vehicle’s CO2 footprint

In order to keep the combustion engine in the game, its impact on air quality needs to be significantly reduced, if not eliminated, Rothbart added. At the same time, it needs to remain affordable in the long run. “We are working on that,” he said. “We see zero impact emissions from ICEs as being possible, and eventually reasonably affordable.” Natural gas, such as CNG and LNG, biofuels and biogas, as well as synthetic fuels, could all prove effective in this sense.

One way to tackle emissions outside of the vehicle is in the production of renewable energy, such as that generated by wind and solar power. This would also help to offset any overt pressure on a national grid as swathes of EVs charge at the same time. “Having more renewable energy in primary electricity production means that it can be used in different ways for the transport sector,” explained Rothbart. Renewable energy can go directly to the grid, before being used to recharge an EV’s batteries. With an FCEV, those electrons generated via solar, wind or hydro power can be leveraged by an electrolyser to generate hydrogen, which can then be stored at a refuelling station.

“It is quite important to follow sustainable principles in daily engineering,” concluded Rothbart. “We need to consider GHG emissions from production processes—particularly when making batteries—and take care to reduce energy use.”