Category Archives: Household

December 2019 Solar Production and EV Performance

The additional capacity for my solar photovoltaic array was finally turned on in the middle of December.  For some reason the monitoring software is screwed up—probably because it is tied to the old inverter that is now powering an array for a friend in northeast Iowa.  It is my hope that the issue is resolved in the next few days and I can start comparing total production of the array.

Regardless, I have a decent idea of how I am doing relative to total consumption versus total production using the readout from my bi-directional meter.  For December I ended up using ~208 kWh more than I produced.  Considering that my system was not operational for half of the month I am going to take this as a good sign that I should now produce more than I consume most months out of the year.  In the past December has been one of the worst for solar production.

Knowing my numbers at the beginning of the year it is my estimate that I will be net positive when it comes to total consumption versus total production even including my electricity usage for driving my Nissan Leaf.

For the month of December I drove my Nissan Lead 574.7 miles at an average efficiency of 5.0 miles per kWh.  This translates into a CO2 savings of ~651 pounds compared to driving my prior vehicle assuming an average carbon intensity of electricity from the grid.

For the entire year, I drove my Nissan Leaf ~7,987 miles at an average efficiency of 5.2 miles per kWh.  I think this is a pretty good average efficiency based on what I am seeing on forums and what not.  This represents a savings ~9,119 pounds of CO2 compared to driving my prior vehicle assuming an average carbon intensity of electricity from the grid.  It also represents ~$1,132 savings in fuel costs assuming I draw power from the grid at my residential rate.

Where Marginal Differences in Performance Matter: Vacuum Bottle Edition

This is the tale of two double walled vacuum bottles:


The white bottle in the picture is an Ozark Trail bottle purchased for about $9.  The blue bottle is a Yeti Rambler 36 purchased for about $50.

Normally, I am of the opinion that marginal differences in performance are not worth the steep increase in price.  Does a $400 puffy jacket really keep you that much warmer than a $200 puffy jacket?  Maybe, but is it worth double the price?

So how does a vacuum bottle costing four and a half times as much justify its price for a marginal improvement in performance?  When it does not burp hot coffee from around one the seals.  In essence the Ozark Trail bottle failed its job to keep liquids warm and inside the bottle.

I was very bummed out to discover little tendrils of hot coffee running down the side of the bottle on consecutive morning commutes.  It did not happen when I filled the bottle with tap water and tried to make it leak by turning it upside down.  Nope, it had something to do with the hot liquid.

Not wanting to wonder if my coffee was leaking on the passenger seat of my Nissan Leaf every workday morning, I got myself down to the local outdoors shop—Soko Outfitters—and spent the money on the ultimate “look at me” piece of hardware in the shop…a Yeti bottle.  I will admit that I was a person that ridiculed and, to some degree, still do the people who spent hundreds of dollars on a cooler to keep beer cold at a picnic.

However, I was facing the binary situation of a non-functional product versus a functional product.  So I girded my loins for the cash register and spend $50 on a freaking vacuum bottle.

How does it work?  It keeps liquids hot and it does not leak.  That seems to be worth every penny.

The Downside of Snow

Unlike a lot of people I actually like snow.  I like snow so much that I spend my hard earned money to strap wooden sticks to my feet and fling myself down mountainsides covered with the stuff.  Come to think of it, when I describe my ski trips like that it does not sound so sane.  I digress.

The only problem that I have with snow is that it covers up my solar panels.  Like the two inches of snow that fell overnight:


After last year’s snowy and cold January and February left my panels snow covered and non-productive I decided to come into this winter prepared.  Enter the SnoBroom:


Okay, the SnoBroom is just the blue foam blade atop the extendable pole.  The extendable pole might be the true star of this story.  It extends to a maximum of 24’ which seemed like a lot right up until I was clearing snow for real:


With the pole alone I was able to clear the first row of panels and a portion of the second row.  You can see on the closest panels that I spent some time with a step stool to get additional height.  Yes, I was able to nearly clear the panels.  No, I did not fully clear my array.

In the interest of full disclosure I need to come up with a better approach to clearing the array.  Snow, aluminum steps, and a little liquid moisture make for a precarious endeavor.  Practice makes perfect, right?

The other reason I did not push the issue this afternoon is that the temperature is supposed to be nearly 40 degrees with sunny skies tomorrow.  The snow will take care of itself this time.

November 2019 Solar PV and Nissan Leaf EV Performance

November was an ugly month for solar photovoltaic production:


Why?  My system was disconnected and shut down due to a planned upgrade.  The guys from Moxie Solar installed an additional 8 panels and the attendant “balance of system” components like a new grid tie inverter.  The 8 additional panels represent an approximate 62% increase in nameplate capacity for my system.  Given the orientation and installation location are virtually the same as the previous 16 panels I expect to see an approximate 62% increase in solar production once the array is powered up.

This has to be one of the most frustrating parts of a solar installation.  The rooftop install and other system components were done in a little more than a working day.  The city inspection was done in about fifteen minutes and done a few days after installation.  The permission to operate and the simple act of flipping the switch?  I am still waiting.

See most of those zero production days in the last week of November?  That is the cost of waiting for someone to come over from the electric utility and watch a person from the solar installer flip a switch.   It is like a bad anecdote about union rules from the 1980s.  Soon…the switch will be flipped soon.

This might also be the last month for a while where I seen an average of over 5 miles per kilowatt hour in my Nissan Leaf.  For the month I drove a total of 619 miles that used 123.8 kWh of electricity at an average efficiency of 5.0 miles per kWh.  At an average carbon intensity, I avoided emitting ~702 pounds of CO2.

What November really taught me is that cold weather kind of sucks for an EV.  My particular Nissan Leaf is not equipped with the heat pump, so it relies on a resistive heater to provide any level of defrost in cold weather.  Most of the time my trips are short enough that I just deal with a cold cabin while the heated seat and steering wheel keep me cozy.  Put three passengers in the car and the windows start to fog up pretty quick with hot breath.  There is nothing so dispiriting as watching the guess-o-meter drop by 30% or more when you turn on the heat.

It is not enough to dissuade me from recommending an EV in general or an older Nissan Leaf in particular.  There is something to be said for taking advantage of a market dynamic like extreme depreciation.  You can have your Tesla Model 3.  I will take my solar panels, Nissan Leaf, and decarbonized home to the bank every day.

The Financial Math Behind Decarbonization

What if I told you that for the price of a base model Tesla Model 3—good luck actually finding one—you could decarbonize your household?

What if I told you that this is not a thought exercise but an examination of steps already taken?

Are you ready?

The price for base Tesla Model 3 is ~$35,000.  That is the price assuming that you can actually purchase the so-called “standard range” model and before any applicable tax credits.  For the purposes of this discussion I am going to leave tax credits aside for the time being.  So, we are working with a starting price of $35,000.

For that price you get an electric vehicle that has to draw power from the grid, which depending upon your locale and power company may support coal fired electricity.  It may also support fracking for natural gas or the nuclear power energy, assuming any of that industry remains in your region.

What else could you do with that $35,000?

Over the course of the past two and half years I have installed solar photovoltaic panels on my roof in two phases.  Why two phases?  Initially, my power company would only allow my roof mounted solar photovoltaic array to exceed my annual consumption—based on average expected production—by ~10% or so.  Considering how little electricity my household used in comparison to the average this worked out to a system of 4.64 kWh.  This initial phase cost me ~$11,000 before tax credits at the state and federal level.

In the past month I added ~62% more capacity to my existing solar photovoltaic array at a cost of ~$7,500.  In the past year I added an electric vehicle to the mix, which has upped my household consumption, in addition to a few winter months in 2019 where my prior panels were covered under deep snow curtailing production.  We also forgot to turn off a garage heater, which ran up the electric bill in February.  All told these changes goosed our consumption just enough to allow me to install an additional eight panels on my roof.

As it stands right now the photovoltaic array on my roof has a nameplate capacity of 7.52 kWh.  This was complete at a total cost of ~$18,500 before any tax credits.  Remember, we are leaving tax credits aside for the moment.  Assuming my household usage patterns hold—including one electric vehicle—this system will produce more than 100% of my household’s electricity requirements for the year.  The estimated excess production should allow me to replace my natural gas water heater with an electric air source heat pump model further reducing my household requirements for fossil fuels.  With the water heater replaced in the next year my household will only use natural gas for the forced air furnace in the colder months.  Trust me, I am looking at options to replace that as well.

What about the electric vehicle?  This is where the power of the market and a realistic assessment of one’s needs come into play.

A Tesla Model 3 is a fine automobile.  Dollar for dollar, it may be the best vehicle on the market right now when one considers its relative performance and environmental bona fides.  However, it still costs $35,000.

In January of this year I purchased a used Nissan Leaf for ~$11,500.  The Leaf had ~33K miles on the odometer, but the battery was in great condition being that the 2015 and later model years utilized an updated architecture that corrected some of the prior model years’ most glaring problems.  A purchase price of more than eleven thousand dollars might sound like a lot, but this was a car that retailed for more than $30,000 when new.  Losing two thirds of car’s value without high mileage is crazy town.  Or, good for the person who can take advantage.

If one can live with a lesser range, one can take advantage of the market punishing these older EVs for not being up to Tesla’s newer standards.  If one drives in town, for the most part, there is no disadvantage.  In almost a year of daily driving I have had just one instance of the range “guess-o-meter” dropping below ten miles remaining and I have never experienced the indignity of “turtle mode.”

How does this all add up?  Total cost for me to purchase an EV to replace all of my daily driver miles and enough solar photovoltaic capacity to power me entire household, including EV electricity requirements, was less than $30,000 before any tax incentives.  Compared to a $35K Tesla Model 3 I would say that I ended up in a better place.  Five thousand or so dollars better, mind you.

This is not to diminish the decision of someone purchasing a Tesla or any other EV.  Rather, it is to illustrate that there is an alternative path to decarbonization that is neither as expensive as portrayed by many and without any appreciable downsides.

The future is now.

This is What the Future Looks Like

Last week the installers from Moxie Solar completed the installation of eight additional solar photovoltaic panels on my west facing roof and the attendant upgrades to the electrical system (e.g. larger inverter).

Here is what 62% additional solar capacity looks like from the road:


See anything?  That is right, you do not see anything out of the ordinary save for a standard suburban house.

Here is what that same additional solar capacity looks like from the west side of the house:


This is what the future looks like.  Twenty four panels—sixteen 290W panels and eight 360W panels—producing green electricity every time the sun sends its rays our way.  These panels do their thing every day without nary a thought or action from me.  Silent and motionless these panels produce clean electricity.  This solar array will produce more than 100% of my household’s electricity needs including an electric vehicle.

If this is not the future than I have no idea of what will come to pass.

Every Fifth Flush is Free

One of the goals I had for 2019 was to replace the toilets in my house with high efficiency models.  A toilet’s efficiency is measured in the amount of water used per flush (e.g. 1.6 gallons per flush).

When my house was built almost ten years ago three 1.6 gallon per flush “builder basic” toilets were installed.  Up until the past year the toilets have worked with relatively little trouble save for the occasional clog from an overzealous use of toilet paper.  In the past month or so, two of the high use toilets have begun to develop the annoying habit of not sealing after a flush so the water runs continuously until someone jiggles the handle.

Repairing a toilet can send someone down the rabbit hole of wildly different parts.  Do you have a 2, 2.75, or 3 inch tank outlet?  Well, if you want to repair that leaky flapper get ready to find out.  Even if you happen to figure out the exact size be prepared for one brand of part to not fit quite right so you spend the day at Lowe’s or Home Depot staring blankly at toilet flappers, repair kits, or the mirage of a six pack of beer to get you through the nightmare.

Or, you can just replace the whole toilet. This is the route that I chose to take.  I chose to install a Kohler Transpose:


I went the complete replacement route over a replacing the “guts” of the old toilet because as I disassembled the old toilet I found the rubber gaskets to be falling apart.  Not enough to cause a leak, but it did cause me to question just how much life was left in the entire system.

The Transpose’s selling point over similar toilets was its smooth sides.  No visible trapway snaking down to the drain hole, collecting dust, and just being kind of a pain in the ass to clean.  Not a problem now.

The new toilet uses 1.28 gallons per flush versus the old toilet’s 1.6 gallons per flush.  The .32 gallons per flush saved equals 1.28 gallons after four flushes, so the fifth is “free.”  At least that is the math that I am sticking to in my head.  A twenty percent savings per flush is a big deal.  Imagine the pressure on our municipal water systems that could be reduced if every toilet suddenly became twenty percent or more efficient overnight.

Per my New Year’s “goal” I was setting out to replace all of the toilets in my house.  I think, based on usage patterns, I am only going to replace the two high volume commodes.  The toilet in our basement is used infrequently and the water savings will hardly make up for the cost/embodied energy of a new toilet.

NOTE: I bought the Kohler Transpose toilet with my own money, installed it of my own free will, and receive nothing of any kind from Kohler.