Electric Cars Don't Use Fossil Fuel, but what's the Environmental Impact and Life Cycle of the Batteries?

Electric vehicles are often hailed as the panacea, or silver bullet, for the transportation sector of the climate debate. However, how many of us truly understand the environmental impact or life cycle analysis of the batteries that must be built, maintained, and disposed of? Is it even possible to recycle a battery from an electric car and how long do they last? If these are questions you would like to know the answer to, then read on.

Most modern electric vehicles use a lithium-ion (Li-ion) battery packs. This includes widely acclaimed models like the Tesla S and Tesla Roadster Sport, and the Chevy Volt.

These batteries are a distinctly different type than what is used in hybrids like the Toyota Prius, Nissan Altima Hybrid, and Honda Civic Hybrid, which all use nickel-metal hydride (NiMH) batteries to date. However, it is important to note that many of these hybrid models will be switching to lithium-ion batteries starting as early as 2010 because of the numerous advantages this type of battery has over conventional NiMH batteries.

Significant advances have been made in lithium-ion batteries over the last 15 years. This is mostly due to consumer demand for small electronic devices, like iphones, that need to stay charged for extended durations of time, charge quickly, and not lose their ability to hold a charge out over time like older nickel-based batteries. 

Battery Production

Where Does Lithium Come From?

Lithium is the 31st most abundant element on earth, but there are not too many places that you can gather lithium in an affordable way. The most abundant source of lithium on the planet that is readily extractable is the Salar de Atacama, an ancient lake bed located 700 miles north of Santiago in Chile. It has been referred to as the Saudi Arabia of Lithium. Bolivia's flat salt desert of Uyuni also has extensive reserves of lithium, which is turning out to be a resource curse, as the current tone of nationalism clashes with indigenous rights.   

How is Lithium Mined?

Lithium mining is a relatively simple process if your an advanced engineering firm. You simply need to extract the brine (salt saturated water) from about 130 feet beneath the desert and bring it to the surface so the water can evaporate. As the water evaporates it leaves the lithium behind. It takes about 1 year for the concentration to reach about 6% lithium, at which point the liquid concentrate is put into tanker trucks and driven to a facility on the Chilean coast to be dried and purified before it is sold to market. 

One-third of the world's lithium carbonate is produced by a Chilean fertilizer and mining company named Sociedad Química y Minera de Chile S.A. (SQM). It is estimated that they are able to produce 1 ton for about $1200 and sell a ton for about $12,000. 

Where are Electric Vehicle Batteries Produced?

Lithium-ion batteries are generally not produced by the auto manufacturers themselves, but rather by firms that specialize in battery production. For example, Tesla partnered with Panasonic to produce batteries for the Roadster Sport and Toyota also decided to partner with Panasonic to overcome a production bottleneck. In the case of Panasonic, they produce their batteries in Japan under strict environmental laws.

How Much Greenhouse Gas Emissions are Associated with Battery Manufacturing?

Roughly 13.5 Metric Tonnes of CO2e are produced when manufacturing an electric car battery.

To determine this figure I used the Carnegie Mellon Economic Input-Output Life Cycle Assessment tool. This tool allows you to determine the amount of greenhouse gas emissions associated with a particular dollar amount spent (e.g., $500) in a specific industrial sector (e.g., leather goods).

For this example I looked specifically at the North American Industry Classification System (NAICS) industry code 335911, Storage Battery Manufacturing, which includes lithium batteries. 

I found that a new battery for a hybrid car costs anywhere from $2,500 to more than $10,000, so I originally decided to use a value of $5,000 for my input variable to determine the amount of greenhouse gases, which gave a value of around 2.5 metric tonnes.

UPDATED ARTICLE NOTES: Based on numerous users chiming in after the first version of this article was published in the comments (see below) I found that a more accurate value for an electric car battery was about $16,000 and that I had wrongly been running the model as if a "Primary Battery" were being manufactured. Therefore, I also changed the model inputs to "Storage Battery Manufacturing".  

Here is an updated graph I generated to visualize the update results showing that manufacturing a Li-ion storage battery emits roughly 13.5 metric tonnes of CO2: 

Battery Use

How Long Do Batteries Last?

It has been estimated that electric vehicle batteries last up to 180,000 miles. 

Tesla estimates that the battery life for their model S will be between 5 and 7 years, but could be as high as 10 years if you take proper care of your battery. I also imagine that the climate you live in has some impact on the battery life. Many of us have experienced that dead cell battery in your ski pants; move it into your underwear for awhile and wahla - your battery works again for a little bit. I would expect that if you had a tessla in southern California it would have a different lifespan than Aspen Colorado.

Battery Disposal

Can You Recycle Lithium-ion Batteries?

Yes. Tesla recycles all of the batteries from their vehicles. In fact, they build the recycling cost into the purchase price of the vehicle, so there is no question what happens when the time comes to turn the battery over. To read more details about this process you can read Tesla's blog

Can You Recycle Nickel-Metal Hydride Batteries?

Yes. Toyota recycles all of their Prius batteries and offers a $200 bounty to dealerships to ensure that the batteries make their way back to Toyota. 

What About Electric Car Greenhouse Gas Emissions?

The greenhouse gas emissions that electric vehicles produces obviously don't come from the tailpipe, but from the electricity production facility. This can be a wind farm, a coal-fired power plant, a natural gas-fired power plant, a solar farm, or any other type of facility that is designed to generate electricity. Therefore, the amount of greenhouse gas emissions that your electric vehicle is responsible for will vary entirely on how the electricity is being produced that charges your vehicle's battery, but that's not the end of the story. 

The efficiency at which small combustion engines found in a typical automobile produce energy that is physically transferred to propelling the vehicle forward is about 20%. In electric vehicles the efficiency transfer from the battery to the forward motion can be as high as 80%. This is a significant leap forward, but that's not the end of the story either. 

Small combustion engines are significantly less efficient at creating usable energy than an industrial-scale power plant; even when you take transmission and distribution losses into account. Therefore, using an electric vehicle, especially one powered by renewable resources, is incredibly efficient.

 

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