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New full LCA highlights complexity of environmental advantages and disadvantages of EVs relative to ICE vehicles; the importance of life cycle thinking

Researchers at the Norwegian University of Science and Technology (NTNU) have compared the emissions resulting from the production, use, and end-of-life of electric and internal combustion engine vehicles (EVs and ICEVs) in a full life-cycle analysis (LCA). They found that electric vehicles (EVs) powered by the present European electricity mix offer a 10% to 24% decrease in global warming potential (GWP) relative to conventional diesel or gasoline vehicles assuming lifetimes of 150,000 km (93,206 miles).

However, they also found that EVs exhibit the potential for significant increases in human toxicity, freshwater eco-toxicity, freshwater eutrophication, and metal depletion impacts, largely resulting from the vehicle supply chain. Their results, they cautioned in an open-access paper published in the Journal of Industrial Ecology, are sensitive to assumptions regarding electricity source, use-phase energy consumption, vehicle lifetime, and battery replacement schedules.

Because the production impacts of EVs are more significant than for conventional vehicles, a vehicle lifetime of 200,000 km (124,274 miles) would increase the GWP benefits of EVs to 27% to 29% relative to gasoline vehicles or 17% to 20% relative to diesel. However, a lifetime of 100,000 km decreases the benefit of EVs to 9% to 14% with respect to gasoline vehicles and results in impacts indistinguishable from those of a diesel vehicle.

EVs offer advantages in terms of powertrain efficiency, maintenance requirements, and zero tailpipe emissions, the last of which contributes to reducing urban air pollution relative to conventional internal combustion engine vehicles (ICEVs). This has led to a general perception of EVs as an environmentally benign technology. The reality is more complex, requiring a more complete account of impacts throughout the vehicle’s life cycle. Consistent comparisons between emerging technologies such as EVs and their conventional counterparts are necessary to support policy development, sound research, and investment decisions.

...The production phase of EVs proved substantially more environmentally intensive. Nonetheless, substantial overall improvements in regard to GWP, TAP [terrestrial acidification], and other impacts may be achieved by EVs powered with appropriate energy sources relative to comparable ICEVs. However, it is counterproductive to promote EVs in regions where electricity is produced from oil, coal, and lignite combustion.

The electrification of transportation should be accompanied by a sharpened policy focus with regard to life cycle management, and thus counter potential setbacks in terms of water pollution and toxicity. EVs are poised to link the personal transportation sector together with the electricity, the electronic, and the metal industry sectors in an unprecedented way. Therefore the developments of these sectors must be jointly and consistently addressed in order for EVs to contribute positively to pollution mitigation efforts.

—Hawkins et al.

To be able to compare EVs to ICEVs, the researchers had to create their inventory with more detail than they could readily obtained from prior public inventories; the study thus also contributes a higher-resolution, transparent comparison of an ICEV and an EV to the publicly available literature.

The new study offers significantly more resolution regarding the manufacture of vehicle components, full transparency, consideration of a range of battery technologies, and includes a broader array of environmental impacts than prior works, the researchers suggested.

The researchers established a common generic vehicle glider and customized powertrains for gasoline, diesel, and EVs. They investigated two types of batteries in the EV case: LiFePO4 and LiNCM. In the use phase, they tracked electricity and fuel consumption, together with their full supply chains. Use phase energy requirements were based on the performance of the Mercedes A-series ICEV and the Nissan Leaf EV, vehicles of comparable size, mass, and power. For the end of life, they modeled treatment and disposal of the vehicle and batteries.

In the study, they assessed six transportation technologies in terms of ten life cycle environmental impact categories: an LiNCM or LiFePO4 EV powered by European average electricity (Euro); an LiNCM EV powered by either natural gas (NG) or coal (C) electricity; and an ICEV powered by either gasoline (G) or diesel (D).

Among the other high-level findings of the study:

  • For all scenarios, human toxicity potential (HTP), mineral depletion potential (MDP), and freshwater eco-toxicity potential (FETP) are caused primarily by the supply chains involved in the production of the vehicles.

  • The use phase dominates for GWP, terrestrial eco-toxicity potential (TETP), and fossil depletion potential (FDP).

  • End-of-life treatment adds only a marginal contribution across all impact categories.

  • The EV production phase is more environmentally intensive than that of ICEVs for all impact categories with the exception of terrestrial acidification potential (TAP).

  • The supply chains involved in the production of electric powertrains and traction batteries add significantly to the environmental impacts of vehicle production. For some environmental impact categories, lower emissions during the use phase compensate for the additional burden caused during the production phase of EVs, depending on the electricity mix. However, this is not always the case.

Lca
Normalized impacts of six vehicles (4 EVs, 2 ICE) across 10 environmental categories: Global warming (GWP), terrestrial acidification (TAP), particulate matter formation (PMFP), photochemical oxidation formation (POFP), human toxicity (HTP), freshwater eco-toxicity (FETP), terrestrial eco-toxicity (TETP), freshwater eutrophication (FEP), mineral resource depletion (MDP), fossil resource depletion (FDP), internal combustion engine vehicle (ICEV), electric vehicle (EV), lithium iron phosphate (LiFePO4), lithium nickel cobalt manganese (LiNCM), coal (C), natural gas (NG), European electricity mix (Euro). Hawkins et al. Click to enlarge.

The shift in emissions that EVs are poised to bring about— an elimination of tailpipe emissions at the expense of increased emissions in the vehicle and electricity production chains— brings new opportunities and risks for policy makers and stakeholders. On the one hand, EVs would aggregate emissions at a few point sources (power plants, mines, etc.) instead of millions of mobile sources, making it conceptually easier to control and optimize societies’ transportation systems. On the other hand, the indirect nature of these emissions— which are embodied in internationally traded commodities such as copper, nickel, and electricity— challenges us as a society. It poses the question of how serious are we about life cycle thinking, and how much control and oversight we, customers, and policy makers believe should be exerted across production chains.

—Hawkins et al.

Resources

  • Hawkins, T. R., Singh, B., Majeau-Bettez, G. and Strømman, A. H. (2012), Comparative Environmental Life Cycle Assessment of Conventional and Electric Vehicles. Journal of Industrial Ecology. doi: 10.1111/j.1530-9290.2012.00532.x

Comments

HarveyD

Who financed the study?

Kit P

LCA was the subject of my thesis for a masters degree in environmental engineering. The three most important things are location, location, location. Kind of like buying a house.

What this LCA is telling us is that zero emission vesicles are really elsewhere emission vehicles or EEV. The environmental impact is where the the electricity is produced. So it depends on the location of your fantasy world.

The power that is going to meet the increase demand is most likely to come from coal-based generation. This makes the EEV 25% worst than the ICE in the figure provided..

Just for the record this is not a new result. For those who bother to read the reports rather than the fluff that passes for journalism would know that.

Bob Wallace

" However, a lifetime of 100,000 km decreases the benefit of EVs to 9% to 14% with respect to gasoline vehicles and results in impacts indistinguishable from those of a diesel vehicle."

Huh? Why would vehicle lifetime drop to 100,000km/60,000 miles? Are they not saying that EVs and diesels have the same impact for the first 60k miles due to manufacturing inputs and then the fuel vs. electricity differences really start to show?

Bob Wallace

"What this LCA is telling us is that zero emission vesicles are really elsewhere emission vehicles or EEV."

That holds, Kit, only as long as the electricity is produced using fossil fuels. Since Europe and the US are moving away from fossil fuels any "elsewhere emission" is only a temporary state.

And wherever the grid is supplied by less than 100% coal (essentially everywhere) "elsewhere" is already better than burning oil.

HarveyD

The energy sources used to compare are always dictated by how/who the study is financed to arrive to the preferred conclusions.

For the last month or so, Canada's current Central government and Tar Sands industries are spending $$$M to convince Canadians and Americans (coast to coast) that Tar Sands are very good for our health, well being, schools, environment, hospitals, Old age, Universities etc. They are financing many University Studies to demonstrate that we could even eat that stuff and feel better. A lot like the Tobacco and Asbestos Industries were doing for 100+ years.

In other words, it is wise to question most studies, specially those paid by the groups concerned.

Bob Wallace

"However, they also found that EVs exhibit the potential for significant increases in human toxicity, freshwater eco-toxicity, freshwater eutrophication, and metal depletion impacts, largely resulting from the vehicle supply chain."

Potential. Don't pour industrial waste into the river. Do stuff the correct way. Reduce, reuse, recycle.

A hammer has the potential to give you a severe headache. If you hit yourself in the head with that hammer.

Metal depletion impacts. EVs use more metal than ICEVs? More copper, less steel. All recyclable.

I'm sorry, this piece seems like a huge piece of nothing and we can expect to see it used for many coming attacks on EVs. Anti-EV folks will drop the "potential" in their attempts to keep us back in the 20th Century.

Kit P

@Bob

Certain assumptions are made about hypothetical solutions like BEV to compare them to the existing data for ICE. If the electricity comes from fossil fuels it is a bad solution from day one and then gets worse. Batteries do not have the property of getting more efficient with age.
So if you you are trying to reduce ghg, the best solution is to not build BEV for general use until you have some data that show there will be a reduction.

LCA are a useful tool when comparing like to like. For example comparing base load power to base load power.

PV on your roof should be compared to rides at Disneyland. Except for those who live in California, most know that Disneyland is a fantasy world. Fun for the children!.

Kit P

“Since Europe and the US are moving away from fossil fuels any "elsewhere emission" is only a temporary state. ”

First that is not true if you bother to check the data instead of the politicians. Second, wind and solar are only temporary. If we get back to LCA, the life of wind and solar equipment is an unverified assumption. There could come a day when there is excess wind generation exists at night in California but the best way to describe it now is a fantasy.

It takes more than a magic wand to make your fantasy a reality. It takes a really good plan, I only bad plans.

HarveyD

It is so easy to pay for a study to have it based on very selective input data. The results always depend on the data used and/or not used. Not too long ago, some smart very selective study came to the conclusion that a huge 4-tonne Hummer monster used less fuel than the Toyota Prius. Many actually believed that non-sense.

It is of the utmost importance to consider who paid for a study. It will always be biased towards the payer regardless of who did the work. That is the power of money.

ToppaTom

It is only common sense to dismiss studies that have undesirable results and accept at face value those that bolster our self image.

In this case I am very skeptical of a study that comes from a strangely named university, supposedly residing in a country I have no proof even exists.

"Norwegian University of Science and Technology in Trondheim" - are you kidding me?.

Nordic, Scandinavian . . isn't that from a Harry Potter book?

It is a core truth and undeniable cultural fact that EVs, windmills and PV panel plants create jobs, are very good for our health, well being, schools, environment, hospitals, old age, universities (REAL universities) and obesity.

Bob Wallace

" the best solution is to not build BEV for general use until you have some data that show there will be a reduction"

I can agree with that. So, we need to be building and driving EVs in the US, Canada and Europe among other places since running EVs off existing grids would cause a lower CO2 emission rate than burning oil.

The rule of thumb is if the grid is 100% coal then EVs/PHEVs produce a slight bit more CO2 than efficient hybrids.

Coal is now contributing about 35% of US electricity. About 30% of our grid supply is natural gas. NG kicks out about half as much CO2 as coal, so our output is about like a grid run on 50% coal.

We're good to go. Bring on the EVs!

ChrisL

I want a BEV because they offer a much nicer driving experience than an ICE vehicle (quiet, smooth, lots of low-end torque, low maintenance, etc.), and do not have to be driven to gas stations to refuel (topped off every morning). When I buy one, I will also put a photo-voltaic array on the roof. (BEV manufacturers are starting to offer them packaged with a special deal on a solar electric installation). The reduced air pollution, reduced reliance on foreign oil supplies, etc. benefits are all gravy.

Bob Wallace

"Second, wind and solar are only temporary. If we get back to LCA, the life of wind and solar equipment is an unverified assumption. "

The correct word is not "temporary" but "variable". Yes, wind and solar are variable, but since cars spend about 90% of their time parked and could be plugged in while parked that makes them incredibly valuable partners for variable supply sources.

Wind farm operators would love a lot of EVs plugged in and controllable via smart metering at night.

As for expected lifetimes of wind and solar, the 30 year old turbines at Altamont Pass wind farm are just now being replaced with more efficient turbines mounted on taller towers.

Those first generation turbines gave us three decades of electricity and we should expect newer technology to last longer. We've got much better monitoring and lubrication systems. Better wind gust forecasting which will reduce shock loads. And some turbines are eliminating the gear trains which are turbine's weak point.

We've now got 40 year old solar panels in use and they are still producing in excess of 80% of their rated capacity. Newer panels should have better contacts and edge lamination sealing so expect panels to last a long, long time.

Bob Wallace

"“Since Europe and the US are moving away from fossil fuels any "elsewhere emission" is only a temporary state. ”

First that is not true if you bother to check the data instead of the politicians. "

I looked at the data. The data tells me that each year in the US we make a higher percentage of our electricity with renewable energy and a lower percentage with fossil fuels. We went from 9.3% renewables in 2008 to 12.7% in 2011. Fossil fuels fell from 70.2% to 67.6%.

And I checked the data for the EU27. Renewables supplied 18.3% share of their total primary energy production. That was a 60.2% (avg 4.8% per year) increase from 1999 to 2009. I would bet they beat that 4.8% the last couple of years the way solar and offshore wind are booming.

Bob Wallace

"PV on your roof should be compared to rides at Disneyland. Except for those who live in California, most know that Disneyland is a fantasy world. Fun for the children!."

My posts are brought to you via Disneyla.., er, solar power.

Solar is much fun for adults who enjoy the electricity it produces.

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