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Electric vehicles won’t eliminate urban air pollution - but they could help (a lot)

Electric vehicles won’t eliminate urban air pollution - but they could help (a lot)

City transportation fleets look increasingly likely to have an "all-electric" future. Image: wikimedia user: mattbuck.

The cost of lithium-ion battery packs for electric vehicles has dropped 60% since 2010 - from US$1,000 to US$400 per kilowatt-hour (kWh) - according to Bloomberg New Energy Finance (BNEF). At the same time, concerns regarding urban air pollution have increased.

Does this combination point to an all-electric future for our city transportation fleets?

The answer might very well be “yes”. But, a shift to electric vehicles wouldn’t necessarily eliminate urban pollution problems.

Air pollution from transport

Today’s diesel and petrol vehicle fleet produces an array of air pollutants - including particulate matter (PM) and nitrogen oxides (NOx) – in addition to carbon dioxide (CO2). Exposure to these pollutants can lead to cardiovascular disease, lung cancer and respiratory illness (e.g. asthma, chronic bronchitis). According to MIT researchers Steve Yim and Steven Barrett, particulate matter from transport alone leads to an estimated 7,500 premature deaths each year across the United Kingdom.

The highest concentrations of particulate matter air pollution in the UK are currently found in Greater London. Furthermore, according to the London Atmospheric Emissions Inventory (LAEI), a distinct majority of this outdoor air pollution comes from transport.

According to the Lancet Commission’s 2015 report, “Health and Climate Change: policy responses to protect public health” a transition to clean energy technologies (including electric vehicles) could have many immediate benefits for public health by reducing air pollution.

Electric vehicles won’t eliminate urban air pollution - but they could help (a lot)

Particulate matter emissions. Reference: Dajnak 2012.

Will urban transport soon be all-electric?

In the face of dropping battery costs, urban areas including London could move to electric vehicles and significantly reduce its particulate matter air pollution. This topic was explored in depth at last month’s Bloomberg New Energy Finance (BNEF) Future of Energy Summit in a panel aptly named "Air pollution, cities, and transport.”

The panel was chaired by BNEF’s Head of Advanced Transport, Colin McKerracher and explored how the transport sector is expected to evolve as it tries to balance 1) meeting demand and 2) compliance with air pollution standards.

In an interview, McKerracher agreed with comments by Aston Martin CEO Andy Palmer, including Palmer’s statement that the future of transport is an all-electric one. McKerracher also stated that “we could get much faster adoption of electric vehicles because of these urban air quality problems and global pollutant concerns.” He went on to say that that:

“There are a few other things [in addition to falling battery prices] that indicate that transportation is moving toward EVs – first, the power sector is getting cleaner every year and so an electric vehicle is cleaner every year. Also, we see policies – like fuel economy standards in the U.S. – that are set to get much more stringent and push automakers towards hybridisation or full electrification. Our analysis indicates that it will be very difficult to meet these existing standards without much more electrification. So, I agree with the statement that the future is largely electric. Though, there will still be some applications like heavy trucks, that will use other things – but the passenger vehicle trajectory is clear.

My long term view is that all passenger vehicles will have batteries and plugs. The question is, will they have gasoline tanks as back-ups too? This split between battery electrics and plug-in hybrids is still uncertain. ”

EVs won’t eliminate urban air pollution – but they could help (a lot)

In these comments, McKerracher captures the important fact that electric vehicles are not truly “zero-emission”. Firstly, their fuel source is not currently pollution free. Secondly, today’s vehicle technologies still produce non-tailpipe emissions.

Electric vehicles are fueled by power plants. In the UK (and the vast majority of the world), these power plants produce air pollution including particulate matter and nitrogen oxides. While EVs could shift pollution away from urban sources (i.e. vehicles) to rural ones (i.e. power plants), pollution would still be released into the air. However, as McKerracher highlighted, this will be less of a problem as the power sector becomes increasingly cleaner.

But, even with 100% pollution free electricity, current electric vehicle technologies still would not be “zero emission” vehicles.

In the previously displayed graph, you likely noted that there are two values displayed for 2008 and that the second was much larger than the first. This difference comes from the fact that the latter value includes particulate matter from tyre, brake and road wear in addition to tailpipe emissions. While nitrogen oxides are purely tailpipe emissions, the size of the bar in this graph shows that a slight majority of particulate matter from vehicles does not actually come from the tailpipe. Even a shift to 100% electric vehicles wouldn’t entirely eliminate this type of pollution.

As falling battery prices combine with increasing attention to urban air pollution, the future of our transport systems could be all-electric. While EVs wouldn’t eliminate urban air pollution, they could certainly help.

Electric vehicles won’t eliminate urban air pollution - but they could help (a lot)

Colin McKerracher at opening of BNEF Summit panel on “Air Pollution, Cities, and Transport”. Image: Melissa C. Lott.