Tag Archives: electric vehicle

December 2020 Solar and EV Efficiency

That’s all folks.  2020 is in the bag—finally—and we can hope for a better year in 2021.

This is what my solar system’s production looked like for the month:

Mediocre is the best word that I can use to describe this month’s production.  Things were not helped by a pair of snowstorms that left the panels fairly well covered for a few days.  You can really see the impact in the middle of the month when production went into a nosedive.

For the month, my household was “in the red” ~396 kWh.  Not great, but decent considering we spent the final two weeks of the month almost entirely at home save for a single day of skiing at Sundown Mountain.

For the year, my household was “in the black” ~1,040 kWh.  Given the major lifestyle changes due to the coronavirus this is pretty good.  There is very little “leakage” anymore in terms of electricity usage being diverted to someone else’s account.  Namely, my employer.  With four people at home almost every day, all meals cooked at home, and most of our miles being driven in an EV we still needed less than 24 solar panels to end the year net positive in terms of electricity usage.

This figure gets even better when you consider the time lost in August due to the derecho, September due to repairs stemming from the derecho, and the slow activation of my solar system addition in January.  We will see what 2021 brings.

In terms of EV numbers, we drove ~431 miles at an average efficiency of 4.8 miles per kWh.  Efficiency suffered this month toward the tail end because of the snow, cold temperature, and carrying four people around in the Nissan Leaf.  With four people in the car the windows start to fog up almost instantly and you are forced to run the resistive heater.  If there was ever an argument for a heat pump it has to be watching what running a resistive heater does to your EV’s range and efficiency.

For the year, we drove just under 6,050 miles in the Nissan Leaf.  This represents a nearly 25% decline from the prior year, but the story is more complex then that.  In June we sold my wife’s idle Subaru Outback.  Since that time the Leaf has been our primary mode of transportation outside of a few longer trips in my truck.  Even with the focus on the Leaf as a daily driver we drove fewer miles than the prior year.   I guess there is at least one good thing to come out of the coronavirus pandemic.

Overall, driving the Nissan Leaf resulted in avoiding just under 7,000 pounds of carbon dioxide emissions assuming that I pulled all of the electricity from the grid at an average carbon intensity for my region.  The savings are actually higher since I tried to time recharging with when my solar array was pumping out extra electrons.  Another benefit of being home all of the time.

November 2020 Solar PV Production and EV Efficiency

November is really the first month during the fall/winter season where the sun seems to lose some of its potency.  The light is flatter and the intensity is less.  It shows when you see solar PV production figures:

Production of ~374 kWh for a month is not bad and it beat my previous November totals by a good measure owing to the additional eight panels that I had installed.  Overall, my household ended the month ~171 kWh “in the red.”  Considering that we are spending every day at home working, our kids are spending every day at home attending virtual school, we are cooking every meal at home, and almost all of our driving is done in an EV that does not seem so bad.  It also makes me wonder about installing some more solar panels so that I can be net positive even in the winter months.  Maybe with all the money we have saved by selling the Subaru Outback in June…

For the calendar year 2020 my household is currently ~1,436 kWh “in the black” or net positive.  Even if December were a horrible month for solar production it is likely that we will end the year significantly net positive in terms of electricity.  I believe that this goes to show that it does not take a major change in lifestyle to live a significantly lower carbon intensity way.  Granted, our household is much more conscious of the impacts of our daily decisions but it is not like this is a perverse episode of Living with Ed.

For the month of November we drove the Nissan Leaf ~523 miles at an average efficiency of 5.2 miles per kWh.  Maybe I am just a very conservative driver who borders on hypermiling, but I get a chuckle out of people talking about getting 4 miles per kWh in their more modern EVs.

For the year so far we have driven just over 5,600 miles in the Leaf which is just more than a 29% decrease in mileage versus 2019.  However, this mileage total represents almost all of our household driving as we sold our Subaru in June.  Before, we might take the Subaru to Iowa City for my daughter’s medical appointments.  Not anymore.  Especially now that UIHC has several ChargePoint stations in their parking ramps.

All in all, driving the Leaf has allowed us to avoid ~6,462 pounds of CO2 being emitted compared to driving our full size truck assuming we pull all of the electricity for the Leaf from the grid at an average carbon intensity for our region.  For most of the year we have been putting electrons in the Leaf from our solar panels because I tried to time charging to periods of high production in the late afternoon.  Until such a time when I have a more advanced EV or charger that allows me to time charging automatically I am stuck doing things old school.  Nothing like waiting for the meter to spin backwards before plugging in.

October Solar Production and EV Efficiency

Is there something happening this week that has everyone’s attention?  Oh right, the fate of the Western world might hinge on what voters in a few states decide.  Nothing quite like staring the end of the world as we know it in the face.

The production from my solar photovoltaic array in October was good:

Unlike the prior two months when a derecho knocked out production in August and a roof replacement knocked out production in September, October was a full month of productive days.  It just so happens that those days are less intense when it comes to the sun.

Regardless, I ended the month ~2 kWh “in the red” in terms of production versus consumption.  So close to net zero for the month.  So close.

For the year, however, my household is “in the black” ~1,591 kWh.  Given how past years have gone my household should end up net positive in terms of solar electricity production for the year by quite a bit.  That is assuming I do not do anything stupid like leave a garage heater on for a couple of days when the temperature is below freezing.

In terms of EV numbers, we drove 557 miles at an average efficiency of 5.5 miles per kWh.  This is down from 5.8 miles per kWh in September and 6.1 miles per kWh in August.  It really shows you just how much of a difference running a heater—my Nissan Leaf has the capacitive heater as opposed to the heat pump—can make in terms of efficiency.  I would be curious to see if a heat pump would make that much difference, but I am not about to head out an buy a new EV.

Compared to driving my truck, we saved ~641 lbs of CO2 assuming that all of my EV’s electricity was pulled from the grid at an average carbon intensity.  For the year, we have saved ~5,866 lbs of CO2 from being emitted using the same metric.  In total, since early January 2019 we have saved ~14,985 lbs of CO2 from being emitted by driving the Nissan Leaf.

Even crazier is the impact that coronavirus and the subsequent changes in daily life have made to our driving.  For the year so far we are down ~36% in terms of miles in the Nissan Leaf, but this does not tell the whole story because that car is now the primary driver for two people in my household.  This summer we sold my wife’s Subaru Outback since it was collecting dust and costing us insurance money each month.  All of those miles have been shunted to the Nissan Leaf and we are still down more than a third.

As of today, we have worked from home for 138 working days.  This represents almost 5,500 miles and ~7,322 lbs of CO2 saved by not commuting.  I do not know what the final accounting for the year will look like in terms of decarbonizing but I have to believe it will be a big one for my household.

Stay safe out there and please make sure to vote.

September 2020 Solar PV Production and EV Efficiency

Well, September 2020 was another month where we were still recovering from the derecho.  How so?  In order to get a replacement roof installed my solar system was removed for about a week and a half in the middle of the month:

Even with the loss of almost one third of the month my system still produced 430.6 kWh.  Production versus consumption ended up 44 kWh “in the red,” which is the first time my household has run a deficit since February.  It is kind of a bummer to run a deficit, but getting a roof on my house before the fall through spring months was a critical repair to be made after the derecho.  A big shout out to the Moxie Solar service crew who got out here in the rain to get my solar panels off the roof so that my roofer could get up there a day later.  It’s a scheduling dance to be sure.

For the year, my household is “net positive” 1,609 kWh.  Even with September’s deficit my household is also “net positive” since the installation of my PV array back in 2017.

In terms of driving, my Nissan Leaf was driven 521.6 miles at an average efficiency of 5.8 miles per kWh.  For some reason my efficiency dived in the last few days of the month.  I had been hovering around 6.0 miles per kWh.  I have no idea why that drop happened.

Compared with my truck, my household saved ~606 pounds of CO2 assuming pulling electricity from the grid at an average carbon intensity for my region.

The crazier numbers are what total household driving looks like compared with prior months and years due to coronavirus.  September’s driving total was down ~31% versus the same month the prior year.  For 2020, my household is down 43% total in miles driven versus the prior year.  This number will probably increase over the coming months as shuttling kids between activities slows down and work from home continues.

Stay safe out there.

August 2020 Solar Production and EV Driving…We Got “Derecho’ed”

Well, we got hit by the derecho in the first half of the month and you can see how that impacted solar production:

August 2020 solar

The power was out at our house from Monday at about noon until sometime Thursday night with intermittent outages through the following weekend as power crews cut in dark neighborhoods.  The bad thing was that it was sunny out for those days, so my PV system lost out on a good amount of production.  The good thing was that it was somehow not hot and humid—in Iowa in August which is almost unheard of—so we did not roast or braise or slow cook.

For the month my PV system produced ~971 kWh of electricity, which would have been well over 1 MWh if we had not lost those days to the derecho.  In terms of production versus consumption, my household ended the month “up” ~305 kWh.  For the year so far my household is “up” ~1,653 kWh.

Even better, August 2020 represented the month when I went net positive since the replacement of my meter two or so years back.  Without warning, my electric company replaced my bi-directional meter with a newer “smart” meter.  I had lost track of my solar production versus household consumption at that time and followed with a few months where my consumption ran high.  Buying an EV and running a space heater in a garage to finish some projects in the dead of winter is no good for your electric bill.  However, my household is now net positive and looking to crush things going forward.  Since February we have been net positive and September is always a good month for excess production because the HVAC requirements are low.  We usually try to get into November before turning the heat on and the AC is off for the year already.

In terms of driving, we drove the Nissan Leaf ~572 miles at an average efficiency of 6.1 miles per kWh or 93.8 kWh total.  Amazingly, the monthly tally for driving was actually up ~8% year-over-year compared to 2019.  Considering we were out of the country for 10 days last August that make sense.  Also worth remembering is that the monthly total now represents almost all of our household driving since we sold my wife’s Subaru in June.

The monthly total for driving works out to an estimated CO2 savings of ~669 pounds compared to my truck assuming that I charge the Nissan Leaf from the grid at an average carbon intensity for my service region.  As noted above, my household is actually running net positive in terms of emission free electricity production—inclusive of all EV charging—so the CO2 savings is greater.  I have been trying to time my EV charging to the time of day when my solar array is pushing out the most electrons so that I am driving on power from the funky yellow sun.

It is crazy to think about but for the year I have ridden my bike more than I have driven my car.  That is 2020 for you.  Stay safe out there.

Are We Focusing on Electrifying the Wrong Thing?

Electric cars are interesting.  Just look at the stock valuation for Tesla.  Like technology companies, Tesla is being valued for something beyond its fundamental performance.  Other electric vehicle makers are being judged in much the same way.

However, I wonder if we are focusing on the wrong path forward for electrification and, thus, decarbonization.

Even an inexpensive electric vehicle is expensive.  For most people in the United States the perceived limitations in range also mean that a lot of people will have a second vehicle for those trips deemed impossible in an EV.  Furthermore, a car is a long term purchase.  The average cycle for buying a new car is measured in years and the average age of cars on the road is close to 12 years. Heck, the average number of new cars the average American is expected to buy in his or her lifetime has been trending down for years.

What is there were better places to put our focus on electrification and decarbonization?

The EV tax credit is estimated to have cost $2.2B between 2012 and 2017 with another $7.5B estimated between 2018 and 2022.  So, about $10B.  What could I do with $10B.

Think about lawn mowers.  The average “life expectancy” for a lawn mower is eight to ten years.  Expect half that for a mower that is not maintained.  Sure, that is within the ballpark of a car’s life expectancy save for the fact that a lawn mower costs a lot less.  For less than $500 you can replace a regular old gas powered lawn mower with a really nice electric mower.

Depending upon the study, a gas powered lawn mower will emit the same amount of volatile organic compounds and nitrous oxides as eleven cars over the same period.  In total lawn mowers represent ~5% of total U.S. air pollution.

In a given year, five million mowers will be sold in the United States.  If the purchase of an electric lawn mower were subsidized, say 50% of a $500 model, it would cost approximately $1.25B to go fully electric.  Just $1.25B to eliminate 5% of America’s air pollution.  Do not even get me started on the whole “where does the electricity come from” canard.

Maybe we are focusing on electrifying the wrong thing?  Just a thought.

July Solar Production and a Little More EV Driving

July has historically been the best month for solar photovoltaic production, but this month did not quite deliver:

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1.14 MWh is good for a month’s worth of production.  However, it is on par with what the system produced in June so I am not jumping up and down with joy.  We shall see what August brings in terms of production as we begin the slow descent into dark winter days.

For the month, my household ended up “in the black” ~353 kWh.  For the year, my household is “in the black” ~ 1.4 MWH.  In fairly short order my household’s energy production should be net positive since I first installed solar panels back in 2017.  From here on out it is just extra electricity from the funky yellow sun.

July was a heavier month for driving as some activities have begun slowly starting back up. For the month, I drove ~467 miles at an average efficiency of 6.3 miles per kWh.  Yes, that is the highest level of efficiency I have ever obtained in the Nissan Leaf and represents a good increase over what I have seen as the consensus average efficiency for the model.   Assuming I pulled all of my electricity for the Nissan Leaf from the grid at an average carbon intensity for my region I avoided ~549 pounds of carbon emissions versus driving my truck.  Here’s the thing, I am running on 100% solar energy now so the carbon savings are even higher.

This month’s mileage total does represent a 48% decline in driving so the coronavirus is still making its presence felt as we are continuing to work from home.  Granted, May was down 83% year-over-year versus 2019.

There is nothing like isolation to help you decarbonize your household.

Over a Megawatt Hour of Solar and a Little Bit of EV Driving in June

June’s solar production ended at ~1.14 MWh.  Yep, my expanded solar photovoltaic array produce more than a megawatt hour of electricity for the month.  That feels like progress:

June 2020 Solar

Overall, my household ended the month producing ~544 kWh more than we consumed.  For the year, we are “in the black” ~995 kWh.  Quickly, I am approaching the point where I am net positive since installing my first solar panels a few years ago.  With July—traditionally the best month for solar production—I could reach that milestone before the summer is out.

Yes, I draw power from the grid.  However, it is my contention that if everyone were attempting to be net positive in terms of their power consumption this world would be a better place.  If enough people were doing just that we would have a huge portfolio of generating assets across the United States that would go a long way to curbing greenhouse gas emissions.  All right, I will get off my soap box.

The total number of miles driven for the month went up compared to prior coronavirus impacted months mainly as a function of actually leaving the house to shop for groceries and taking children to their limited activities for the summer.  Still, I only drove 254.3 miles for the month of June at an average efficiency of 6.2 miles per kWh.

Compared with my truck—which is an untrustworthy mechanical beast that left me stranded on the side of the interstate—I saved ~298 pounds of carbon dioxide being emitted, assuming that I pulled all of the electricity that I required from the grid at an average carbon intensity for my area.  Obviously, I am pumping out quite a bit more solar than required by my household so the actual emissions savings are probably even greater.

The crazy thing over the past three months has been just how much our household driving has been reduced.  For April, May, and June my driving is down 82%, 83%, and 54% respectively.  This takes into account that we have been using the Nissan Leaf for almost 100% of our local and regional trips.  So much so that my wife sold her car to her brother.  Talk about savings.  Plus, there is so much more space in the garage now.

May 2020 Solar Production and EV Efficiency

To paraphrase Dickens, it was the best of times—most electricity generated via my solar photovoltaic array every—and it was the oddest of times—all of my household’s driving total a little more than 150 miles.

First, my household’s solar photovoltaic array generated more than 900 kWh of clean, green electricity:

May 2020 Solar

The interesting thing is that back half of this May was kind of gray.  There was a week span—easy to see on the daily production bar chart—where the sun did not poke through a low level of clouds.  Things picked back up at the end of the month to push the monthly production over 900 kWh.  My hope is that June can come in at more than 1,000 kWh.

In terms of production versus consumption, we ended up “net positive” just over 400 kWh.  This I a good number in and of itself, but it is even better considering that it represents my household’s entire energy usage.  Due to coronavirus we have had two people working from home full time, two kids attending school from home, my sister-in-law living with us while she is between jobs, and cooking all of our meals at home.  There has been very little energy “leakage” save for ordering pizza in one night because my sister was craving the most Iowa thing of all time—taco pizza from Casey’s.  Yes, pizza from a gas station is a big deal for some reason.  I do not get it, but I was not born here.

On the opposite spectrum is my driving in the Nissan Leaf.  For the month, almost our entire household’s driving came to just under 155 miles at an average efficiency of 6.0 miles per kWh.  Compared to my truck, I saved ~181 pounds of carbon dioxide from being emitted assuming that I pulled the electricity from the grid at an average carbon intensity for my service region.  This month I made sure to plug my Nissan Leaf—all told twice—during the height of the mid-day sun when my solar array was pumping out the watts.  Running on that funky yellow sun, baby!

The crazy thing right now is the sheer reduction in driving.  Just my driving, not including my wife’s driving, is down ~82% in April and ~83% in May.  As we are both working from home and not shuttling the children to activities our driving is down double or more whatever total mileage I have avoided driving.  That is a crazy reduction in such a short period of time.

Onward to June.  Stay safe out there.

April 2020 Solar PV Production…the Most Ever

My solar photovoltaic array’s production for April 2020 was the most my system has ever produced:

April 2020 solar

All right, this is less a function of any solar intensity and more a result of my adding an additional eight panels to my array at the end of 2019.  Nevertheless, over 840 kWh of clean, green electricity is a nice month.

The story gets better.  The delta between my system’s production and consumption was 396 kWh “in the black” meaning my home was better than net zero.  It was net positive electricity for the month of April.  I still have to do something about my home’s natural gas fired water heater and furnace.  Coronavirus has kind of put a dampener on any major purchases for the moment.

As expected, we did not drive very much at all this month.  I took the Nissan Leaf out for 115.0 miles at an average efficiency of 5.7 miles per kWh.  This represents 20.2 kWh of energy usage and a carbon emissions savings of ~133 lbs versus driving my truck assuming that all of my electricity was pulled from the grid.  Which, as I noted above, my household was quite positive this month when it came to electricity production.

Those 115 miles represent almost all of the driving for my entire household for the month of April save for a couple of trips in our ICE vehicles that we took to keep the fluids moving.  After this “adventure” we might consider paring down our personal vehicle fleet.

What is crazy about this whole not driving thing is the cumulative impact of not driving.  As of today my wife and I have worked from home for 31 work days.  Using an average miles per day of 22 we have avoided driving ~1,364 miles between the both of us just by not going to work.