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Recycled – June 30, 2021

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Renewables “On Fire”

The theme that renewable energy is cheaper than some kinds of fossil fuels keeps recurring. The Guardian reported last week that solar and wind are often cheaper than coal, noting that the cost of solar and wind have dropped 85% and 56% respectively over the last decade. Last fall, the IEA said Solar is now the cheapest electricity in history. In January 2021, the US EIA forecast that 84% of new capacity would be zero carbon. In fact, according to IRENA (the International Renewable Energy Association) global installs of renewables last year hit a record. And finally, in the 3rd episode of the Big Switch, University of Texas post doc researcher Dr. Joshua Rhodes talked about how Texas (home of big oil!) now deploys the largest wind generation fleet in the United States.

The energy industry is building zero carbon capacity, and this will be a key factor in the effort to decarbonize global supply chains. Should we expect to see the entire grid become zero carbon? That’s probably unrealistic, for now.

For starters, there will always be a need for a reliable energy source that can be turned off and on at will. Large scale energy storage solutions, such as massive battery systems, will get us part of the way there. However, unless new technology, or new nuclear installs, bring us the instantaneous generation that fossil fuels offer it’s unlikely fossil fuels will go away completely. We will need fossil fuel or nuclear generation, and then appropriate abatement strategies.

In addition to the reliable energy source need, the grid itself is constructed around a paradigm of centralized generation, and then transmission to substations, and then homes. It’s a forward feed system that presumes we will truck fuel to generation sites, generate power, and then distribute the power forward for consumption. The impact of this is that generation tends to be placed close to consumption sites, in order to minimize transmission losses. But you can’t truck the wind, or the sun, to a convenient place to generate power. The other challenge is reverse flow. Feeding energy bi-directionally into the grid from what are today’s consumption sites creates a whole new set of problems. It’s likely the grid itself will need to be updated.

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Batteries Part 2

Last week’s piece on batteries generated questions from readers. Specifically two:

  1. What about the environmental impact of disposing of the battery?
  2. What is the carbon impact to manufacture an electric vehicle (EV)? How does it compare with a conventional vehicle with an internal combustion engine (ICE)?

Let’s start with the Battery Disposal and Recycling. I’ll have more on the supply chain footprint for vehicles in a future post.

Battery Disposal / Recycling

The short answers are that we haven’t needed to dispose of or recycle EV batteries at scale, yet; and we also can’t do it yet, at scale.

Batteries which reach end-of-life as automotive batteries haven’t actually reached “end of life”. Most have between 50% and 80% of their useful capacity left. However the batteries become slower to charge, slower to deliver power impacting performance of the vehicle, and reduce the range. So the batteries are currently being given a “second life”. Manufacturers are using them in applications, like storage walls and utility grid storage.

Recycling is not only desirable, but it also makes sense economically, and most of the battery is recoverable. Up to 90% of the battery can be recovered.

Currently, according to this IEA report from 2020 (page 183) we have the global capacity to recycle 180,000 tons of batteries annually. In the same report, the IEA forecasts the demand will grow by a factor of 50 by 2030, and by a factor of 650 by 2040. So, it’s not a concern for today, but it will be tomorrow. A lot of voices are being raised about this right now. The Union of Concerned Scientists has written calling for public policy to be established, National Geographic has written a lengthy piece about the need to build recycling capacity, and the BBC has also recently reported on battery recycling.

We haven’t needed to do it because EV’s are relatively new to the market, and because the batteries are lasting longer than anticipated. Tesla, for example, warranties their batteries for 120,000 miles. However, according to Tesla CEO Elon Musk himself, the batteries in the Model 3 are good for 1,500 charge / discharge cycles which he estimates to be between 300,000 and 500,000 miles.

Real-world driving has shown these claims likely to be true. It appears, for example, that the Model 3 and Model Y will probably be able to travel 400,000 miles before experiencing degradation of 20%.

But when we do need to start recycling at scale, there are multiple options available, and continuing research to improve.

And the last point, of course, is that we should have confidence that recycling capacity will come on line at scale. Not only does it make sense environmentally, but at $45k/ton cobalt (to name just one of the minerals required) is simply too valuable to discard it.

Last thought: warranties and recycling / end-of-life policies will likely vary by manufacturer. When considering the purchase of an EV, also consider the manufacturers battery disposal policy as you make your decision.

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Batteries

Electric vehicle critics will often tell you that the environmental cost of the batteries is the “dirty little secret” that nobody is telling you about. The claim is that the manufacturing impact of the batteries is so high that we might as well just keep burning gasoline. The origin of this statement is an early and flawed study from 2017.

Let’s examine their claim in more detail.

Battery trends

Battery technology is advancing rapidly. You can see this in the price curve. In December of last year, Bloomberg NEF reported the first instances of vehicle batteries priced at below $100/kWh. At $100, most analyses show EVs priced equivalently to internal combustion engines. For comparison, a decade early that price was $1100/kWh. That means that 10 years ago, the price of the 53 kWh battery in Tesla’s original roadster was over $50,000. It’s no wonder those early Roadsters were so expensive!

The environmental cost of manufacturing vehicle batteries is also falling. A recent study estimated the manufacturing impact of current battery technology at 75 kg CO2e/kWh of battery capacity, down from 89 kg in 2019.

Analysis

The assertion made by the EV industry is that the increased environmental impact of manufacturing the vehicle is offset by the decreased impact of using the vehicle. Is that true?

To figure out the answer to that question, we need to know the CO2e impact of running a conventional vehicle vs an EV. Then, let’s add in the CO2e impact of the battery pack, divided over the expected lifetime of the battery, and we should have our answer.

For the sake of simplicity, let’s assume that the manufacturing impact of a conventional vehicle and an EV is roughly the same, excepting that the EV has the added impact of the battery pack. It’s not entirely true, because the conventional vehicle has a higher carbon cost to build than the EV (without the battery), but for the sake of simplification, let’s assume that they are the same.

My previous vehicle, a 2015 Ford Fusion, averaged about 23 mpg in actual usage. Ford rated it for 28 mpg, but I tracked my gasoline purchases over the lifetime of the vehicle, and it was roughly 23 mpg. I may have a bit of a lead foot. Gasoline combustion produces an estimated 18.95 lbs of CO2e per gallon used. Annually, I drive around 10,000 miles, which means that car was producing 8,226 lbs of CO2e annually.

My new vehicle, the Tesla Model Y AWD, is rated by the EPA for 28 kWh / 100 miles of driving. The Tesla should use about 2,800 kWh of electricity to drive the 10,000 miles I drive in a year. Now all we need to know is the CO2e costs to generate the electricity. According to the EPA, in the United States, the electricity industry as a whole produced an average of 0.92 lbs of CO2e per kWh of electricity generated. So, assuming that my power utility emits the same CO2e as the EPA average electrical utility, my CO2e costs will be 2,576 lbs. More on that in a minute…

FordTesla
Miles Driven10,00010,000
Electricity Used0 kWh2,800 kWh
Fuel Used435 gal0 gal
Unit Emissions18.95 lbs / gal0.92 lbs / kWh
CO2e Emitted8,226 lbs2,576 lbs
Annual operating emissions comparison

So for me, my old Ford emitted 5,650 lbs more CO2e annually than my new Tesla does.

Now let’s get back to that battery pack. Recall that the manufacturing CO2e impact of a battery is about 75 kg CO2e / kWh of capacity. So manufacturing the Tesla’s 75 kWh battery will emit about 5,625 kg of CO2e, which converted to lbs is 12,375 lbs. And then we have a simple calculation.

Years to "break even" = Battery Manufacturing CO2e / Annual CO2e savings.  

So, for me, it will take about 2.2 years before the manufacturing impact of the battery is recovered completely.

My Utility is PSE

I buy my energy from Puget Sound Energy here in the King County, WA area. PSE’s generation mix is roughly 1/3 renewable, 1/3 coal, and 1/3 gas.

SourceEmissions
Coal2.2 lbs / kWh
Natural Gas1.0 lbs / kWh
Renewable0 lbs / kWh
Blend1.06 lbs / kWh

Compared to the national average, PSE is actually a pretty dirty utility. My Tesla driving will generate 2,968 lbs of CO2e annually. And my emissions “payback” will extend to 2.35 years. What a calamity!

Fortunately, PSE has a green energy option, which we have chosen for our household. For an extra $.01/kWh (about $15/mo) we buy an energy mix which is generated 95% from solar and wind, and 5% from biogas. Biogas has about the same emissions profile as NG, which means that the PSE clean energy option produces about 0.05 lbs CO2e / kWh. Some folks consider biogas neutral environmentally, but let’s leave that for another day. In any case, my new Tesla’s CO2e footprint using PSE green energy is now reduced to just 140 lbs CO2e annually, and the “pay back” time for the battery is now just 1.5 years.

Over the 5 years I owned the Fusion, I estimate my emissions at about 41,000 lbs CO2e. I expect the Tesla to be a third of that. Automobiles have a lifetime of about 200,000 miles. Over 200,000 miles the Ford will emit 165,000 lbs CO2e. And if I own the Tesla that long? 15,000.

Your numbers will vary, but the calculation is not hard to do. And no matter how you do the numbers, there simply is no case that the environmental impact of EV battery manufacture outweighs the benefit of not burning gasoline to run a vehicle.

Case closed.