Electric cars are presented as a solution for society’s needs to curb emissions and reduce petroleum consumption, but are they really environmentally friendly?
The way researchers try to answer this question is by a “cradle-to-grave” life cycle analysis. This normally takes into account three phases – 1) the manufacturing process, 2) a car’s life in the hands of the consumer, 3) and what happens to it post-consumer.
Compared to gas and diesel vehicles, electric cars are yet under a microscope by skeptics, policymakers, others, and studies sifting various aspects of these three phases have sought to quantify just how clean they really are.
After all, we frequently hear how coal remains in the U.S. electric grid that powers electric vehicles (EVs), and concerns over batteries are also repeated.
Beyond greenhouse-gas emissions, analyses may also assess impacts from acid rain, ozone pollution, algae blooms, water and materials required, and total energy demand.
The short answer is accepted science sides with EVs as impacting the environment less overall.
“We examined six peer-reviewed academic studies and found that in every case, electric vehicles win by a substantial margin, with estimates ranging from 28 to 53 percent lower cradle-to-grave emissions than conventional vehicles today,” wrote the National Resources Defense Council as published by Grist in August 2013.
This fall the Union of Concerned Scientists expects to release new findings updating previous work. It will use assumptions about vehicle lifetime and updated facts on the getting-cleaner U.S. electricity mix to reflect current U.S. lifecycle environmental impact values.
“I think our results will still show the general trend that EVs generate more emissions during manufacture but the savings during use are much larger,” said Dave Reichmuth, senior engineer, UCS Clean Vehicles Program.
Polite Science Versus Ugly Truths
Typical analyses between cars that run on electricity versus those that run on petroleum agree on parameters of what to analyze.
Step outside that for a minute in your imagination, and one could open a Pandora’s box potentially proving EVs a winner over internal combustion by a much larger margin.
Often unquestioned are some of the hidden costs society now accepts – what economists call externalities – to a petroleum-dependent way of life.
For example, cradle-to-grave analyses do not normally factor the sum total of all military involvement to protect petroleum, defend against terrorists angry over America’s oil-related foreign intervention, and other such things to maintain the petroleum paradigm.
While the U.S. is now producing more oil than it has since the early 1970s, oil remains a global fungible commodity with price not controlled by the U.S.
The U.S. has been to war and remains involved to maintain peace in oil producing regions. These factors have an environmental impact – not to mention dollar and life cost – but this does not usually count in electric-versus-internal-combustion analyses.
EVs do not need oil-supply protection in regions where terrorists hate America. They run on domestically sourced energy whose price is locally controlled.
Of course, if you do think in these terms, you open a can of worms of infinitely more variables, and where does it stop? Counterpoints could also be raised, and these too would need to be weighed.
But at this point, this is an abstract notion. The only point here is there are actions and consequences that transcend many a cradle-to-grave discussion which agree not to look at a proverbial man behind the curtain holding up the transportation sector.
It is what it is. Duly noted for your consideration. And with that, following are highlights from generally agreed-upon science.
Manufacturing – EVs Are Dirtier
The Union of Concerned Scientists does concede that all told, making EVs is more environmentally harmful than making gasoline cars.
“Building an electric car produces more global warming emissions than a conventional gasoline car, largely due to battery production,” writes the UCS’ Don Anair echoing other such admissions by his colleagues.
A study by Argonne National Laboratory examines “Energy and Environmental Impacts of Lithium Production” combatting the commonly held notion lithium mining is so harmful, but the net impact from battery manufacturing is still a factor.
Before EVs ever get to a consumer they are like a lot of college kids – in debt – but EVs start to make up for their carbon debt as soon as they are put to work.
“However, these emissions are dwarfed by those from using a gasoline car,” continues Anair comparing emissions of driving EVs versus driving internal combustion cars.
His comment came in a rebuttal article countering an electric car critic who has used influential media outlets to write opinion pieces posed as science. Articles like “Green Cars Have a Dirty Little Secret” published March 2013 in the Wall Street Journal present what Anair termed “cherry-picking data, bizarre assumptions” to allege EVs are a boondoggle.
Anair this time was answering the same writer who published this February in USA Today what EV advocates have called misinformation, and willful spreading of fear uncertainty and doubt.
“It is time to stop our green worship of the electric car,” wrote the author in USA Today. “It costs us a fortune, cuts little CO2 and surprisingly kills almost twice the number of people compared with regular gasoline cars.”
Sounds scary! In response, Anair noted that a Leaf should last much longer than a mere 50,000 miles suggested as a low-point possibility. If a Leaf died in 50,000 miles it would not pay back the manufacturing costs. The electric car critic also picked on the emissions believed resulting from a 90,000 mile lifespan to make another point which Anair batted down.
“[M]ass-market EVs are in an early stage of deployment and new EV models with different technology approaches (e.g., range, battery chemistry, body design and materials) are rapidly entering the market,” wrote Anair. “Manufacturing processes are likely to evolve and mature over the coming years, as are recycling processes that could change the amount of EV materials being recycled, reused, or scrapped.”
Consumer Use – EVs Make Up The Deficit
While an EV may come to the consumer in environmental debt, it starts to pay back quickly. The Union of Concerns Scientists in its updated 2014 State of Charge report found since 2012 the number of Americans who live in regions where grid emissions to power EVs are cleaner than a 50 mpg Toyota Prius had increased from 45 percent to 60 percent.
On the flip side, other studies have found regional fluctuations. One such study was “Life cycle air quality impacts of conventional and alternative light-duty transportation in the United States” by the University of Minnesota.
This pointed out deficiencies in the U.S. grid yet needing to be addressed.
“Our research found that the source of electricity matters very much in determining how “environmentally friendly” an EV is,” said researcher Julian Marshall. “If EVs are powered by coal-based emissions, they are much dirtier than if they are powered by renewable-based electricity; coal-based EVs are dirtier than conventional vehicles.”
Today there are no grids that are 100-percent coal powered, but variances between the cleanest and the dirtiest are marked. For example a Nissan Leaf charged in Southern California is EPA rated at 120 grams/mile effective upstream greenhouse gas emissions. The same car in the dirtiest region of Denver, Colorado nets 290 grams per mile.
This fact is an indictment of the U.S. energy grid, not the car, which itself is zero emission, but as a proposed alternative to gas, it does vary in its effectiveness. The EPA says the national average car is 480 grams per mile, so the Leaf still wins in greenhouse emissions. It’s only a question of how much.
The EPA data however also does not factor more than greenhouse gases, and environmental impacts from both internal combustion tailpipes and upstream gasoline refining, as well as electricity production do involve other toxins and particles.
Generally, EVs are still cleaner, but they have room to improve – or the grid does that is.
“We absolutely need to be ramping down our use of coal,” writes Anair contary to suggestions it merely be cleaned up.
Meanwhile the EPA is developing national power plant standards, he observes, which may be stronger than proposed. In January, California committed to 50-percent renewable energy by 2030 and existing renewable rules are already in place in a dozen states.
What this means is EVs stand to be cleaner over time. The electric grid actually emits 10-times the greenhouse gases petroleum production does, so has much more potential to clean up its act, which is expected.
Gasoline tailpipe emissions meanwhile are also getting marginally cleaner and federal rules in place through 2025 mandate it.
As for production of gasoline and diesel, with increased reliance on shale oil as well as Canadian oil sands, these are not getting as much cleaner as the production of gasoline and diesel stands to, but the Argonne national Lab suggests it has potential.
“Gasoline and diesel well-to-wheel GHG intensity remains about the same,” said Argonne’s Michael Wang, Senior Scientist – Energy Systems, of emissions over the past few years. “The Canadian oil share has increased but appears at a very decelerated pace recently. Future share of oil sands in U.S. crude remains unclear because of U.S shale oil production increase. The U.S. shale oil shale has increased significantly. Bakken shale oil has high well-to-wheel GHG intensity because of gas flaring. North Dakota has plan to reduce gas flaring in the future. The pace and magnitude of flaring reduction remain to be seen. Thus, my opinion is future gasoline and diesel GHG intensity will probably change little, with upward potentials.”
Post Consumer – Probably No Worries
The jury is partially out as first-generation mass-market EVs are only four years old and not many are worn out yet.
That said, post-consumer re-use of batteries is being explored and recycling is an option too.
[A]dvanced vehicle batteries are unlikely to be simply thrown away; they’re too valuable,” writes the UCS’ Rachael Nealer. “Even once they’re no longer suitable for automotive use, they retain about 80 percent of their capacity and can be re-purposed to provide grid energy storage to facilitate the integration of variable renewable resources, such as wind and solar.”
Nealer observed 95 percent of conventional auto parts are recycled so this should apply to EVs.
“It is worth noting that conventional lead-acid car batteries are consistently the most recycled product for which the EPA provides data [PDF], with a recycling rate of 96 percent,” wrote Nealer.
In short, EVs will end their life differently but their environmental impact should not be much worse than internal combustion vehicles, if at all. The most potentially damaging compared to conventional vehicles, their lithium-ion batteries do have value, are expected to be capitalized upon, and research is ongoing to maximize this potential.