Category Archives: Mobility

Spring has Sprung: March 2019 Solar Production and EV Stats

Can you tell the exact time when the snow finally melted in Iowa and it began to feel like spring?  I will give you one guess looking at the image below:

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It was like someone opened a door and spring rushed in looking for treats like a good boy.  I said it last year and I will say it again this year…I need to get a roof rake so that I can brush the snow off when it refuses to slide off my solar panels.  The way these things go it will probably be a very light snow year next season and the roof rake will sit in the garage unused for months.

It is my hope that April sees a production number on par with the prior year as the previous few months have really been mediocre in terms of solar production.  There is something ironic about getting an electric vehicle at the same time that my solar production fell off a cliff.  Oh well.

Speaking of the Nissan Leaf it also had a month when it became obvious that the weather had turned.  I drove 603.4 miles at an average efficiency of 5.0 miles per kWh.  This compares with average efficiencies of 3.6 and 3.9 miles per kWh in January and February respectively.

Two factors played into this efficiency increase: warmer weather that resulted in less use of the resistive heater and better knowledge of how to wring out mileage from the vehicle.  It is kind of amazing how you can optimize your driving along a route without resorting to any crazy hypermiling or vehicle modification. This is the kind of improvement that makes me wonder how much efficiency we can wring out of the transportation system without having to resort to draconian measures.

Over the course of the past two and a half months I have driven a total of 1583.6 miles in my Nissan Leaf.  That has saved 1731.9 pound of CO2 versus my prior vehicle and cost a total of $49.34.  The emissions and cost numbers are based on me using grid electricity for the entirety.

As an aside, I utilized a public charger for the first time this month.  In practical terms it was super easy.  I pulled up to one of the two spots at my place of work, tapped my Chargepoint RFID keycard, and got to charging.  There has been a lot of talk about infrastructure for charging and how it impacts the widespread adoption of EVs.  In my experience, the publicly available charging infrastructure is not the major hurdle to adoption for a lot of people.  Unlike urban areas, the suburban area that I live in is rife with attached garages where people can charge their vehicle at home overnight.  Within line of sight of my garage are two houses with Tesla Model 3s and in conversations with the owners I have found that they also rarely, if ever, utilize public chargers, including Tesla’s vaunted Supercharger.  It is just not necessary for the majority of driving that takes place in an average day.  Heck, I only used the charger at work to ensure that my Chargepoint card worked so that I could take my Leaf down to Iowa City in the summer.

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Twenty Days in January with My Nissan Leaf

The biggest step that I have taken to decarbonize my transportation was to buy a used 2015 Nissan Leaf.  Depreciation and other market forces made purchasing a lightly used electric vehicle an easier decision than it had been in the past.  It also helps that I had already wired my garage for 240V operation, making charging that much faster than relying on legacy 120V outlets.

January 2019 was a weird month and I only owned the Leaf for twenty days of the month due to a lengthy process to get the car delivered.  No one wants to hear that their newly purchased car was on the delivery vehicle that went off the interstate in high winds.  Combined with a week or more of polar vortex and the first appearance of significant snow this winter I have a hard time making heads or tails of my driving results.

Anyway, for the twenty days that I had possession of the Nissan Lead I drove a total of 352.5 miles (~17.6 per day) at an energy efficiency of 3.6 miles per kWh.

Until the temperatures dropped into colder than a well digger’s rear end on the shady side I was average around 4.5 miles per kWh.  This goes to show you how much an impact using a resistive heater can have on your EV’s energy efficiency.  I have also come to discover that the Nissan Leaf’s battery has a thermal management system that will heat the battery in extreme cold to prevent “freeze up.”  That is just more energy used to make heat and not drive the wheels.

Regardless, I am still saving in terms of fuel cost and carbon emissions.  Based on my prior primary vehicle—a 2013 Ford F-150—I saved $12.73 in fuel costs and 372.1 pounds of carbon dioxide.  This assumes that I drew all of the power to move my Nissan Leaf from the grid, which when I rack and stack January’s solar production looks very likely.

A Resistive Heater is the Enemy of Efficiency

I do not know if the weather of the past few days qualifies as a “polar vortex,” but it is really cold.  It is grab you by the spine when you walk outside to your car cold.  It is stay inside even if all you have to eat are frozen waffles cold.  It is make sure you have a dirty thirty of American lager in the fridge cold.  Seriously, the number of people I saw picking up thirty packs of Busch Light at the grocery store the night before the cold snap started was a little surprising.  What says staying in because it is bitterly cold better than a beer that has to be cooled to near freezing just to be palatable?  I digress.

The problem with the extreme cold—it was negative double digits without making any consideration for wind chill—is that I am forced to use my Nissan Leaf’s heater to prevent the windows from turning into an ice and breath fog mess.

Range anxiety is not something that I suffer from on my roughly ten mile round trip to work, but watching the estimated range drop from the mid-90s to the low-70s is disheartening.

The culprit is the resistive heater used by the Nissan Leaf.  In a regular old internal combustion engine powered vehicle “waste” heat from the burning of gasoline is used to heat the cabin.  Electric cars do not have any waste heat to tap into, so these vehicles must rely on auxiliary heaters.  The simplest method is to use a resistive heater.  Do you have a toaster?  That is a resistive heater.  Do you have a space heater?  Resistive heater.  Incandescent light bulb?  A better resistive heater than a light source.

This is electric heat at its simplest.  Push electric current through a metal wire and the physics of a material’s particular resistance will produce heat.  The problem with the simplicity is that it is a relatively inefficient way to produce heat.

To combat the loss of range and limit use of the resistive heater for the cabin most Nissan Leafs are equipped with heated seats—front and rear—and a heated steering wheel.  The idea being that if your immediate body is warm—especially your hands—the less you will rely on the cabin heater.  It all works when the winter temperatures are reasonable.  When the polar vortex comes calling you just give in to the inefficiency.

Newer Nissan Leafs with higher trim levels come equipped with a heat pump that uses significantly less electricity when conditions are right.  However, as the air cools below 32 degrees Fahrenheit the heat pump’s effectiveness is reduced and the good ol’ resistive heater gets to work.  You cannot “move” heat from the ambient environment to the controlled environment if there is not heat to “move.”  Even the fancy Leafs have a problem in the extreme cold.

Thankfully, it’s so cold no one really wants to go anywhere.  Range is not an issue when you are staying at home all weekend.

The Inherent Efficiency of an Electric Vehicle

“But you’re still using electricity from the grid!” drunk Uncle Carl says at the family gathering he is invited to once a year.  “And that electricity comes from coal.”

On the whole, the United States produces ~30% of its electricity from coal.  Some states make considerably less electricity from coal.  California makes almost no electricity from coal.  Idaho makes almost no electricity from coal.  You get the idea.

The thing is that even if my Nissan Leaf is using electricity from the grid it is still more efficient on a per mile basis versus almost any other car or truck on the road.  It is more efficient in terms of carbon emissions per mile and cost per mile in dollar terms.  Let’s see how that breaks down.

A gallon of gasoline, when burned, produces approximately 20 pounds of carbon dioxide.  In 2016 the fuel economy of new cars and trucks in the United States reached 24.7 miles per gallon.  Therefore, on a per mile basis the average new car in the United States emits 0.81 pounds of carbon dioxide.

A kilowatt hour of electricity has a carbon intensity of approximately 1 pound.  This figure obviously differs depending upon your utility, grid operator, locale, etc. but it works as an average for the United States.  Over the course of the last couple of weeks I have averages 4.2 miles per kWh in my Nissan Leaf, which is probably low since I have been forced to use the relatively inefficient resistive heater.  Therefore, my EV “emits” 0.24 pounds of carbon dioxide per mile driven.

For those needing a refresher in math, 0.24 is less than 0.81.  In fact, it is about 70% less.  Now, imagine you are charging your EV in Idaho where each kWh of electricity has a carbon intensity of 0.2 pounds.  That would be a decrease in carbon intensity of about 94%.  As the grid gets cleaner the miles driven by your EV get cleaner as a result.  Your regular old car with an internal combustion engine will still emit the same old carbon dioxide year after year.  In fact, it will likely emit more as it gets older and less efficient.  Just saying.

Furthermore, imagine I am charging my Nissan Leaf with electricity derived from the solar panels on my roof.  This represents a decrease in carbon intensity of 100%.  Talk about demand destruction.  Take that Uncle Carl!

The Difference a Plug Makes

These two cords may look similar:

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Both are about 25 feet in length, which makes for one heavy bag.  Both utilize EVSE to ensure safe charging.  Both have SAE J1772 plugs.  Both, at the most basic level, move electrons from the socket to my Nissan Leaf.

However, there is a major difference between the two:

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The one on the top is the charging cable that comes with the Nissan Leaf.  The plug looks familiar to anyone in the United States because it is a standard household plug providing for 120V.  The one on the bottom is an aftermarket charging cable designed to work with 240V via a NEMA 6-20R receptacle.

For some reason—probably related to a tool I owned at the time—I wired my garage for several 240V, 20A circuits.  Now, with an EV in the house, I can just purchase an aftermarket charging cable that corresponds to the plug type and I am good to go for Level 2 charging.

Why is Level 2 charging important?  It makes an EV like the Nissan Leaf as livable as a regular old gasoline automobile.  In a few hours the vehicle can charge enough for an entire day’s worth of driving via Level 2 charging as opposed to overnight on good old Level 1 charging.

The first time that I charged my Nissan Leaf with the Level 2 charging cable it went from 50% to fully charged—showing 101 miles of potential range—in something like 3 hours.  I wish I could be more exact, but I was just checking in on it when I thought about it while cleaning the house.

The Level 1 charging cable is nice to have in the car for emergencies or if you know your destination only has standard household current available.  Overnight charging is not so bad in practice.  It is just slow and requires a little more planning.

The other benefit to having a pre-installed 240V circuit in the garage is that I can get the benefit of Level 2 charging via a $200 charging cable versus spending much more on a dedicated charging station.  Dig it.

Now my garage is my gas station.

The Nissan Leaf has Arrived

This is my Nissan Leaf:

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There are many like it, but this one is mine.

It is not new.  It is used and that is where the story begins.  The frequently touted advice is for someone to buy a used car because depreciation begins the minute someone drives a car off the dealership lot.  Now, one can argue against this logic because there are zero used cars sitting on the lot for sale with a few miles that cost a lot less than the new cars on the same lot.  Sorry.

However, with this 2015 Nissan Leaf it is a story about depreciation and market forces.  New, the 2015 Nissan Leaf S started at ~$30K.  Three years and ~32,000 miles later I was able to buy the same vehicle for less than $11K before tax, title, and license.  For those of you keeping score at home that is a decline in value of about 65%.  Granted, some of that decline in value is related to the $7,500 federal EV tax credit which pushed the effective new price down.

Nonetheless, the decline is dramatic.  This is where market forces come into play.  People want the latest and greatest.  With EVs that trend is exacerbated because the latest and greatest frequently get you a lot more range, which is the single biggest issue with EVs for most drivers.  If you are willing to live with a more limited vehicle you can really score a great deal on a used EV right now.  I am living proof.

Here is what living with a compromise solution looks like.  My Nissan Leaf shows a range of anywhere from 90 to 100 miles on 100% battery charge when I activate the car:

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When new the range was within that range.  See what I did there?  I digress.

Therefore, the degradation of the battery pack that plagued earlier Nissan Leafs does not seem to be impacting my car’s battery pack.  This is due to the 2015 model having the so-called “lizard architecture” that is better suited to handle temperature extremes, particularly high heat.  A common complaint of the Nissan Leaf from the EV community is that they designed the vehicle to use passive, ambient air cooling for the battery pack.  Not so good in the southwest United States but it should not be too much of a problem in eastern Iowa.

Overall, this vehicle is not much of a compromise compared to anything.  The range allows me to travel round trip to Iowa City—some 36 miles to the south—without having to worry about recharging.  Although there are plenty of spots to plug-in down south.

Going 1x a Little Sooner than Expected

Well, this happened on the Cedar Valley Nature Trail today:

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I do not know how to describe my front derailleur being bent ninety degrees the wrong way, the chain being pinned against the large chainring, and the large chainring being bent about half an inch out of true.  Oh, look at what the front derailleur did when pinned against my bottle cage:

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It’s hard to tell from this picture, but you can see just how out of true the large chainring is as a result:

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No bending back a few teeth with a pair of pliers for this repair.

I have some of the components for the switch to a 1x drivetrain like I did on the dirtwagon a couple of seasons back, but most of the stuff is going to have to be acquired in the near term.  And to think that I was trying to make it the whole riding season before deciding what path to take with the drivetrain.