Hi,

I've been trawling through the net trying to find a figure for the carbon footprint of an all-electric lithium-ion battery (and/or Prius). I'm led to believe that they're energy intensive and perhaps moreso than an ICE. In which case I'd like to compute the carbon payback period.

You guys seem to know what you're talking about, so could anyone quote me a figure?

Thanks,
Eamon

 

What units?

Actually I think you should start by going to Wiki and check out the entries for "CNW Marketing." The simple answer is every peer reviewed, academic paper has found that the operational energy is typically +80% of the total energy. What this means is the manufacturing foot-print is very small when compared to the four times larger fuel consumption and equivalent carbon foot print:

o - manufacturing carbon
oooo - fuel consumption carbon

So are you still interested in the manufacturing carbon foot-print? If so, let us know the units you want for the answer. There are many potentially confusing ways to express carbon produced to manufacture some unit, say pounds of ICE or battery.

Bob Wilson

 

Thanks for the quick reply, Bob! Read some of the links there, CNW are certainly a secretive bunch and that Hummer comparison was obviously bogus.

I know how hard it can be comparing apples with oranges. What piqued my interest in the matter was a presentation I went to which mentioned the Mitsubishi iMIEV fully electric vehicle. There's also a petrol version which is to all intents and purposes the exact same vehicle but for a different drive train system.

The figures presented (presumably sourced from Mitsubishi) were:

Petrol Version: 0.056l/km or 0.54kWh/km.
Electric Version: 160km range, 16kWh battery; therefore 0.1kWh/km

So that's 5 times less energy per km. To me that sounds too good to be true. Have you any insight into that? Ideally if you had the specific figures for the i-car and the iMEV?

If not then something like the embodied energy (and or carbon) per kWh of lithium-ion capacity. Or for the petrol version I suppose the correct metric would be embodied energy per pound of engine as you suggested.

A side issue is the batteries, I understand the Prius battery is guaranteed for 180000 miles or 10 years but howabout these all-electric vehicles? Don't the lithium batteries degrade over time... would they last that long? And then there's the Morales issue in Bolivia!

I want to be a believer but I'm a natural skeptic unfortunately!

Thanks for your time,
Eamon

 

I'm no expert but I've heard that the tank-to-wheels efficiency with an ICE (internal-combustion engine) is about 18%, and that electric gives 80+%, so a 4x difference is not unreasonable. However, the electric comparison used 16kWh as the energy used: that's a understatement: you need to include, at least, the charging losses: the to get 16kWh into the battery takes more than 16kWh of electricity.


With that adjustment you have a more fair comparison: from the consumer's source (electric outlet or gasonline pump) to the actual mileage. I won't even bother to compare the costs in dollars, carbon, or political, of the different ways of producing gasoline vs. those of producing electricity.

 

The ICE has about 10X the moving parts as an EV. Within those parts friction, and thus heat, is created which makes them so inefficient.

Also, many people worry about the batteries and what will happen to them when their life cycle is over. I can tell you from personal experience that there are many electric cars out there with over 100,000 miles, on their first battery pack with virtually no range degradation. With an ICE, after 100,000 mi usually something major leads to replacing, which creates more footprint for the car. As far as battery recycling goes, every car on the road (with maybe a few exceptions for cars that are 100+ years old) has a battery in it. With hundreds of millions of batteries on the road, there are already battery disposal and recycling methods. The newer EV batteries are almost 100% recyclable, unlike the lead-acid batteries in most cars. As electric cars and hybrids become more mainstream, there will be more battery recycling programs, just like oil for gas cars.

 

I think I know why I was puzzled. That figure assumed the electricity was generated from wind. If it comes from fossil fuels in a CCGT it's more like 40% total efficiency against the total efficiency of 15-20% for a ICE.

The presentation was interesting in that, at least in Ireland's case, the charging of electric vehicles at night (and during the day) might allow for a greater network efficiency and higher wind utilisation. So if a grid uses renewables, the proportion of renewables that should be used in comparing ICEs and BEVs is an interesting question.

While I'm here, I'd like to get your perspective on the lithium question. I've come across a couple of articles about lithium. It seems there's some dispute about whether we have enough lithium or not - with the two protagonists seemingly William Tahil and Keith Evans. Tahil comes at it from an economic perspective arguing that lithium production is not scalable. Evans, a geologist, claims that Tahil vastly underestimates the lithium reserves but doesn't to my knowledge present an economic analysis. What you reckon?

It seems it's still an open question but there is a purportedly comprehensive report by TRU, a special metals firm, which was commissioned by Mitsubishi. The title is "Lithium Demand-Supply Outlook through 2020". It will be presented at a conference on the 26th January and the presentation will apparently be made available afterwards. Maybe that will further the discussion...

Eamon

 

I actually haven't looked into peak-lithium at all. However, battery technology is constantly improving, and by 2020 (or sooner) we might have an even better battery chemistry. In just over a decade, we have gone from EV1s with lead acid, to EV1s with NiMH, to the Volt with Li Ion. Of course, there were other EVs that used those chemistries, as well as others, but those offer a nice comparison since they are all from GM and all use the major chemistries.

 

And it really makes a difference where the power comes from. As soon as the first all electric plug in is available it will be mine. I have a 6KW solar system on my roof which supplies my house with 110% of electricity, 10% is being sold back to the local power supplier, so I could use the 10% overhead to put "fuel" in the car

 

Solar panels and electric cars (PV+EV as we like to call it) is a great system. Once your PV system has been paid off, you are running your car on FREE, CLEAN, RENEWABLE, DOMESTIC energy. However, even with our current grid, which is about 51% coal (last time I checked), electric cars are still cleaner than even the cleanest hybrid.

If you want a plug-in car, check out this petition to the automakers to build plug-ins.

 

I'm with ya there, but can you quote me a current price per MW for solar? I heard one figure of $400-500 against like $70 for coal. I know technology is marching on, so do you know a current figure? It should be noted that in general the cars will be charged at night and the sun shines during the day. There is no economical way to store electricity.

While solar can still displace some daytime carbon, large numbers of cars would require wind, which tends to blow more at night. You have your plains - the saudia arabia of wind - so if you had a better grid then that's great.

What concerns me is the scaling of lithium. I'm not convinced there's either enough lithium or that it can be produced fast enough to have vast numbers of people switch to electric in the forseeable future. Neodymium is used in making electric motors, also. There's barely any, with 95% coming from China. There's technology in the pipeline to obviate the need for that, so that shouldn't be an issue.

Your thoughts?