Pareto Principle and Plug-in Hybrid Vehicles (PHEV)

Some time ago, I ran into an article written by Dan Neil on the Wall Street Journal titled “Next to Tesla, Plug-In Hybrids Are an Illusion of Eco-Consciousness”. He argues that plug-in hybrid vehicles are essentially a joke. He states that they are designed to make the driver feel better about their environmental footprint, but that their green-house gas reduction is negligible.

Mr. Neil draws his conclusions from driving a 986-hp Ferrari SF90 Stradale on Swiss roads and noticing that the all-electric range was depleted only after 8 miles of driving. Really? Should we take a car that costs over half a million dollars and that most of us have only seen on magazine pictures to draw conclusions about the merits of plug-in hybrid electric vehicles (PHEVs)? He also points to other auto makers like Bentley and Porsche, arguing that their PHEV are mostly PR tools meant to meet CAFE standards. There is some truth behind all this, but my direct experience drives me to a very different conclusion. Those of us owning PHEVs can in fact considerably impact our emissions if we chose to plug them in, even if it is only once a day, even when their electrical-only range is relatively limited.
First, let’s provide some context related to common complaints about EVs in general. The argument goes that we are just transferring emissions from the tailpipe to the power plant producing the electricity. For a car that is plugged in to be truly green, the power plant generating the electricity would have to be carbon-free as well, right? Yes, this would be a nice to have but not a requirement for EVs to be a lot more environmentally friendly. Without going into all the technicalities related to tailpipe particulate matter emissions, nitrous oxides by-products and efficiencies from internal combustions engines, we can refer to a recent publication by the Union of Concerned Scientists. Below are the Mine-to-Wheel Life Cycle Global Warming Emissions of Different Passenger Vehicle Types:

This data is for pure EVs vs gasoline vehicles. For PHEV the impact will be more moderate and highly dependent on the driving patterns and driver’s plug-in discipline. But my point and my reference to Pareto is that we don’t have to go all-in to make a big impact.

I own a 2016 Ford Fusion Energi, a plug-in hybrid with a 7.6 kWh battery designed to provide an initial average of 20 miles of electrical only range. Five years later I get an average of 16 miles, but the rationale is still the same. By comparison, a Tesla model 3 with a standard range of 262 miles has a 50kWh battery. This is where my analogy to Pareto’s principle comes into play. Can I make an 80% impact in my green-house gas emissions with only a 20% effort? My Ford Fusion Energi battery is about 15% the size of a Model 3. Is that enough to make a dent?

According to AAA, the average car is driven 29 miles a day. This means that a Ford Fusion Energi would be cycling the battery daily. On an average day, it would have been depleted and fully used. Good thing. If you have something you might as well use it.

According to recent figures from Argonne National Laboratory, a single car lithium-ion battery pack (of a type known as NMC532) could contain around 8 kg of lithium, 35 kg of nickel, 20 kg of manganese and 14 kg of cobalt. There are concerns about the environmental and social impact associated with the extraction of these minerals for use in electric battery vehicles. An EV’s battery has higher quantities of these raw materials than a PHEV. In the case of the Model 3, if it were to be driven only 29 miles a day, recharging would technically only need to be done every 9 days. Sounds like too big of a battery for fully cycling every 9 days. However, none of these designs can be based on averages, they are meant to address the occasional long drive and range anxiety. This is the fear of not finding (or not having the time for) a recharging station nearby when the battery is getting depleted.

Let’s go back to my particular case and examine it in light of Pareto. My odometer currently reads around 70,000 miles. This means I am driving about 11,600 a year, or 32 miles per day. Pretty close to the national average. I only charge my car once every night at home. My current lifetime average is 54 mpg. The official average mpg of a regular gas-powered 2016 Ford Fusion is 26 mpg. This means that a relatively small battery, combined with a daily grid charge and average driving habits can reduce gasoline consumption by more than half! I find it hard to grasp that we currently have the technology at hand to double the mileage efficiency of the average passenger car in the USA and that somehow this has not yet become more mainstream.

As with other key habits in life, small changes can lead to big results.

-Cesar Prieto