March 19, 2018

The attraction of electric vehicles (EVs) comes from zero emissions while driving. However, the environmental performance of EVs remains a highly debated topic. The argument is that the lifecycle of EVs (manufacturing to operating) remains carbon intensive, and is no less intense than a conventional vehicle (also known as the ‘long tailpipe argument’). In the past, Tesla’s own Elon Musk has argued that even with natural gas, the most popular form of electricity production in the US, Tesla vehicles still produce fewer emissions than conventional ones. And therefore, this article puts the spotlight on EV lifecycle emissions and factors that affect emission output.

The materials, components, and processes are significantly different in an EV, meaning the distribution of emissions do not compare equally to conventional vehicles. The operation of a conventional vehicle accounts for as high as 90 percent of lifecycle emissions, making the manufacturing a small proportion. In contrast, EV emissions come solely from manufacturing and charging.

An EV has one crucial component that a conventional vehicle does not, a lithium-ion battery. Emissions from producing the battery pack come from extracting the raw materials such as lithium, cobalt, and copper. The Union of Concerned Scientists (UCS) has compared emissions for both vehicle types during the manufacturing process.

Life-cycle global warming emissions from the manufacturing and operation of gasoline and battery-electric vehicles

Source: UCS. Note: U.S average grid emissions are used to calculate manufacturing emissions for vehicle comparisons.In the context of mid-large size vehicles, on average EVs produce much lower vehicle lifecycle emissions. Breaking down the vehicle manufacturing component, gasoline and EVs perform similarly. Battery manufacturing notably raises the emission count, particularly in larger vehicles. As a result, EVs overall produce higher emissions from production.

However, conventional vehicles produce much higher emissions from their operation, close to double that of an EV. Meaning that EV manufacturing emissions are more than offset when combined with operation (charging) emissions.

With that said, the carbon intensity of manufacturing and operation depends heavily on geographic location.

Why geography matters

In the last week, the UCS updated vehicle emission data from 2017. And, found that on average EV driving on electricity in the US is equivalent to 80 miles per gallon (MPG) in a conventional vehicle. Near a 10% efficiency increase on the previous year.

MPG equivalent to EV emissions from driving

Generally speaking, the higher the MPG for conventional vehicles, the cleaner the EV emissions. The degree of change state-by-state gives you an indication of the sources of electricity currently being utilized.

There is a direct correlation between renewable electricity generation and EV emissions. Coal use is in decline and is expected to maintain the downward trend. On the other hand, the use of renewables such as hydropower, solar, and wind is on the rise. Looking forward, it is possible that all power plants will be renewable, as the cost to install is considerably lower than a coal or natural gas plant. As a result, life-cycle emissions for EVs will continue to decline.

Noteworthy, The Royal Society of Chemistry took the analysis one step further, looking at the impact of the most common electricity sources on EV lifecycle emissions.

The source of electricity used to power EVs can significantly influence life-cycle GHG emissions and gasoline consumption of these vehicles.

The analysis shows electricity production for a battery-electric vehicle produced by a hydropower plant produces five times fewer lifecycle emissions than a coal-fired power plant. On a state level, California is leading the way. However, the majority of states have work to do to level the playing field.

But, no matter which state you live in, proactive EV owners can dramatically improve their carbon footprint by changing certain habits. For more information, a recent article discusses the impact of charging at various points of the day and the benefits of integrated solar.

Second life

As EVs reach the end of their life, battery capacity will remain. As a result, battery producers are experimenting with ways to reuse EV batteries in a less demanding environment, hence creating a ‘second life.’ Nissan in the UK has already launched a used EV battery program serving as home storage units. Moreover, Nissan and Renault have previously announced plans to build a 100-megawatt power storage plant in Europe, powered by used EV batteries. The plant will have the capacity to power 120,000 homes.

The reuse of batteries will prolong their life before being recycled, and therefore reduce the emissions of an EV battery since they will operate over an extended period. Researchers also suggest that second life batteries will be suitable for grid applications, and even create revenue streams by selling energy.

While the first generation of EVs may not expire for some time, forward-thinking approaches will be necessary to optimize the usability of EV batteries and, in turn, reduce lifecycle emissions.

Conclusion

Even in the most carbon-intensive environment, EVs produce lower lifecycle emissions over a conventional vehicle. However, the amount of lifecycle emissions an EV produces is highly dependent on location. In the US, EVs manufactured and operated in the North West are much cleaner than those in the South East. And therefore, the more electricity created by renewables, the cleaner an EV can become. Dirty coal power plants and are in decline, and renewable plants are in the ascendancy, maintaining a positive outlook for EVs.

An EV battery is an entry point to improve life cycles emissions. By 1) advancements in battery technology and production materials, and 2) recycling and second life options. Exploring the uses of second life batteries is very much in its infancy. However, first entry movers have demonstrated the potential ways to utilize used batteries. Further experimentation is likely. Ultimately, extending battery life reduces lifecycle emissions in the long run.

And so, EVs are cleaner than conventional vehicles no matter the lens you look through. And, unlike conventional vehicles, EVs have the potential to become even cleaner.