365 Days of Climate Awareness 362 – Life Cycle Assessment of Electric Vehicles

There are dozens, if not hundreds, of Life Cycle Assessments (LCAs) for electric vehicles (EVs—let’s hear it for acronyms!), and to be honest, I can’t claim to be any kind of expert in them, or in the relative merits of the many different ones available. The same premise in LCAs holds true of any peer-reviewed science: transparency in sources and methods allows other researchers to verify or dispute your work. Scientists can be a jealous lot, so this system works reasonably well. A number of LCAs have been suggested to me and I have to admit I’ve only gone through a few. With time, I’ll review more, but unlike Tony Stark, I didn’t become an expert overnight. So the rest of you Avengers can just lay off for now. I need an espresso.

All illustrations from The Fuel Institute LCA for electric vehicles (EVs). Categories of the literature review.

The Fuels Institute is a nonprofit organization funded by a range of corporate sponsors including large retailers like Wal-Mart and large oil companies like Aramco, Philips and ExxonMobil. A list like that might make the results suspect but I thought, not having a deep knowledge of the field, a report with likely more conservative associations would provide a useful baseline for comparison to other studies. Furthermore, the report contains side-by-side comparisons between internal combustion engine (ICE) vehicles, hybrid electric vehicles (HEVs), and battery electric vehicles (BEVs).

Greenhouse gas (GHG) emissions found by various LCAs for EVs throughout the 2010's (WTW = "Well to wheels", i . e. energy production and consumption.)

The report begins with a literature review of other LCAs of a range of passenger vehicles (from economy cars up to double-decker buses). The different studies showed a wide range of greenhouse gas (GHG) emissions estimates, based on differences in vehicles and methods. Other reports focused specifically on battery life, efficiency and recycling, and the total operating cost (TOC) over the course of a 10-year or 1-200,000 mile span.

GHG emission estimates across the life span of internal combustion engine (ICE) vehicles, hybrid electric vehicles (HEVs) and battery electric vehicles (BEVs), for 19,000 miles (right) and 200,000 miles (left). ICEs are less emissions-intensive through the first (approximately) 19,000 miles, and then fall progressively farther behind EVs the more they are driven. 

Possible progress in battery effectiveness versus trends in ICE efficiency.

The LCA itself breaks the vehicles down into three main categories:

• Glider (body, chassis, interior, exterior and components)
• Powertrain (battery to engine to wheels)
• Fluids

These categories are then applied to:

• Sourcing (extraction)
• Manufacture
• “Well-to-tank” (WTT), i.e. energy production (whether petroleum or electricity)
• “Tank-to-wheels” (TTW), i.e. energy consumption by the vehicle
• Disposal & recycling

Estimated Total Ownership Cost through ten years, ICE vs HEV vs BEV.

Impact of recycling on battery GHG impact.

This analysis shows that internal combustion (ICE) vehicles, hybrid (HEV) and battery-powered (BEV) vehicles are roughly similar in CO₂ equivalent (CO₂eq) emissions after 19,000 miles driven. But after 200,000 miles driven, HEVs are responsible for 28% less CO₂eq than ICEs; BEVs, 41% less.

Possible future trend in EV GHG emissions.

Life cycle emissions from buses.

Tomorrow: life cycle assessment of a wind farm.

Be brave, be steadfast, and be well.

The Fuels Institute

Carbon intensity of battery (BEV) vs hybrid (HEV) vehicles.