Third Year’s tracking of Hybrid Garage use.

So, it’s been three years since I’ve started tracking our garage’s EV vs ICE use.

As I previously wrote (three years ago on my Minimizing Gas Use article; on my update two years ago; and the one from last year) we drive a hybrid garage.

For those that need a refresher, a hybrid garage is one where some of our cars are EVs and the others are internal combustion engine (ICE) cars. As a family that is a part of the rEVolution, why do we still have ICE cars, it’s because we’re not as good as those that have gone to an all electric lifestyle. Hats off to them, but there are just times that I like to use vehicles that happen to use gasoline.

This winter” was supposed to be better than any of the previous “winters”, but we did not brave the mountains with our fifteen year old BMW X5. The X5 lets us go to the mountains around LA when there are restrictions to drive when the snow is fresh.  Additionally, when we need to buy large items to move, we’ll use this same workhorse to help us move them.  Granted the Model S does have a LOT of space, but we prefer to beat up the X5 with hauling stuff rather than put the Model S to work.

That being said, I understand the costs of our addiction to oil and gas and we continue to try to minimize our gasoline use.

In preparing for the last article on Celebrating Four Mostly Electric Years, I noticed that I had transposed some statistics and noticed that I had overstated the EV miles by 36,000 miles, so I wanted to make sure to correct that.

Three years ago, I started tracking the number of miles my household used ICE vs. EV to see what percentage of our private car travels are electric and what part are powered by internal combustion engines.  Our methodology was to count the miles driven in rental cars to this spreadsheet and the miles that we’ve lent our ICE vehicles (and EVs) to our friends and family when they visit Southern California.   This is why I created some tracking spreadsheets and tracked mileage for a year.   The results year over year are still impressive even with the mileage transposition error in year 2.

In the first year of the study, we drove EV a total of 81.20% of the time and ICE 18.80% of the time.

In the second year of the study, we drove EV a total of 92.64% (vs. what I thought was 94.78%) of the time and ICE 7.36% (vs. what I thought was 5.22%) of the time.

As a whole, the household (as defined earlier, my wife and I and when we lend the cars to family and friends) drove about 46,000 total miles (both EV and ICE in the previous period) in the first year, about 40,000 miles in the second year, and we drove a total of approximately 41,000 total miles in this third year. That’s approximately the same number of total miles between years one and year two.  Even though a good number of those miles were the 8,245 miles of coast-to-coast driving from our Here, There, and EVerywhere trip in May 2015.

Because of the error in Year Two’s calculation, I thought that we would be close to 150,000 EV miles this year, but still at 126,000 All EV miles since we started driving EVs.  For the study, we’re closer to 112,000 EV miles and 14,000 ICE miles for a study average of 88.7% EV vs 11.3% ICE three year average.  Definitely an upward momentum.

Looking at the monthly figures, for the third year shows a big blip in the ICE use for month 34 and that is mostly December 2015 and my sister and her husband was visiting us and most of those miles on the X5 was because we had lent them our ICE car for that month.  The approximately 1400 miles of ICE that was driven that month is more than half the total ICE miles for the year.  Until we have an EV to lend out to family, we’ll have to take those spikes.

Here’s to hoping that this next year’s study will have a greater EV momentum.  And we continue to look forward to seeing what else we can achieve with our hybrid garage next year.  Perhaps another coast-to-coast EV journey.

Second Year’s tracking of Hybrid Garage use.

So, it’s been two years since I’ve started tracking our garage’s EV vs ICE use. As I previously wrote two years ago on my Minimizing Gas Use article and on my update a year ago, I do drive a hybrid garage. For those that need a refresher, a hybrid garage is one where some of my cars are EVs and the others are internal combustion engine (ICE) cars. As a family that is a part of the rEVolution, why do we still have ICE cars, it’s because we’re not as good as those that have gone to an all electric lifestyle. Hats off to them, but there are just times that I like to use our vehicles that happen to use gasoline.

This past “winter” was better than last year’s “winter”, but we did not brave the mountains with our fourteen year old BMW X5. The X5 lets us go to the mountains around LA when there are restrictions to drive when the snow is fresh.  Additionally, when we need to buy large items to move, we’ll use this same workhorse to help us move them.  Granted the Model S does have a LOT of space, but I’m not one of those brave souls to carry “cargo” in them.

Last year we also had our BMW 328iC Convertible. But we sold that now that we’re more comfortable removing and re-installing the roof on the Tesla Roadster. So, on those days that we feel like driving around Sunny Southern California with the top down, we just use the Roadster.

That being said, I understand the costs of our addiction to oil and gas and we try to minimize it.

Two years ago, I started tracking the number of miles my household used ICE vs. EV to see what percentage of our private car travels are electric and what part are powered by internal combustion engines.  Since we travel a little bit, I’ve decided to count the miles driven in rental cars to this spreadsheet and the miles that we’ve lent our ICE vehicles (and EVs) (ICE is now singular over the course of the second year of this study) to our friends and family when they visit Southern California.   This is why I created some tracking spreadsheets and tracked mileage for a year.   However, the results from last year to this year are impressive.

In the first year of the study, we drove EV a total of 81.20% of the time and ICE 18.80% of the time.

In the second year of the study, we drove EV a total of 92.64% of the time and ICE 7.36% of the time. 94.78% of the time and ICE 5.22% of the time. [Correction from 3/10/2016, discovered transposed number in tracking miles a year later.] We sold our second ICE car in Month 4 of the second year (or 16th Month overall). Additionally, we did try to rent EVs on trips as much as possible, unfortunately, even in areas of the country that have EVs available to rent, the vehicles were rented out ahead of the time of our trip there (specifically Honolulu and Orlando). We tried to rent an EV on a trip to Portland, however, at the time, there was no onsite EV rental at PDX International Airport.

As a whole, the household (as defined earlier, my wife and I and when we lend the cars to family and friends) drove about 46,000 total miles (both EV and ICE in the previous period) and we drove a total of approximately 39,300 55,000 total miles in the second year. That’s an increase of 9,000 decrease of 7,000 more miles of total driving of which 52,500  36,422 of those total miles were EV. That’s nearly 6,000 more miles than ALL the driving that we did during the first year of the hybrid garage study.

Interestingly, I did a quick 31,310 Tesla Model S update the day before the end of the second year of the study period and I had a lifetime Model S efficiency of 308 wH per mile. At the end of the day of the second year of the study, that average went down to a more efficient 307 wH per mile.

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Throughout the past year I’ve been using 308 wH per mile for my calculations. Now going to have to use 307 wH per mile. That achievement is something.

One of the things that I was hoping to announce in this post is, as a family, we’ve reached 100,000 all EV miles across all three EVs that we’ve leased or owned, but sadly at the end of the second year of the period, we’ve been able to get to 99,665 miles on all the EVs that we’ve owned or leased. Now if we were to count our loaners and the few times we’ve been able to rent EVs in this count, I’m sure we’re well over 100,000.

Looking forward to seeing what else we can achieve with our hybrid garage next year.

First Year’s Tracking of Hybrid Garage use.

So, it’s been over a year since I’ve started tracking my garage’s EV vs ICE use. As I previously wrote a year ago on my Minimizing Gas Use article, I do drive a hybrid garage. For those that need a refresher, a hybrid garage is one where some of my cars are EVs and the others are internal combustion engine (ICE) cars. As a member of the rEVolution, why do I still have ICE cars, it’s because I’m not as good as those that have gone to an all electric lifestyle. Hats off to them, but there are just times that I like to use my vehicles that happen to use gasoline.

This past “winter” was not indicative of what we usually use our thirteen year old BMW X5 for, but when it snows, it’s fun to go up to the mountains around LA and play in the snow.  The X5 lets us do that when there are restrictions to get up the mountain when the snow is fresh.  Additionally, when we need to buy large items to move, we’ll use this same workhorse to help us move them.  Granted the Model S does have a LOT of space, but I’m not one of those brave souls to carry “cargo” in them.

Prior to adding the Roadster to the garage, we kept the 328i Convertible for those days that we wanted to drive around with the top down.  We still have it and waiting for the start of summer to sell the vehicle when we expect to have the best demand for them.  (Send me a note around May if you’re interested in buying our 2008 328i Convertible).  Granted the BMW Convertible is a lot easier to take the top down and up on than the Roadster, this will probably be the next ICE to be sold from our garage.

That being said, I understand the costs of my addiction to oil and gas and try to minimize it.

So, about a year ago, I started tracking the number of miles my household used ICE vs. EV to see what percentage of our private car travels are electric and what part are powered by internal combustion engines.  Since we travel a little bit, I’ve decided to count the miles driven in rental cars to this spreadsheet and the miles that we’ve lent our ICE vehicles (and EV) to our friends and family when they visit Southern California.   This is why I created some tracking spreadsheets and tracked mileage for a year.   However, the results were stupefying.  After 365 days of meticulously tracking the mileage consumed by my household for EV vs. ICE for the year, the old 80/20 rule asserted itself with up to two decimal points of the percentages.

We drove a total of 80.05% of the time and ICE 19.95% of the time.  Granted, this sample for the past year included three EVs from November 2013 to March 2014 as well as several long-term (a week or greater) visits from family and friends who we lent our vehicles to.  Furthermore, a majority of this past year’s sample was with the Active E as the only EV in the garage, and as a result we were only constrained by the 80-100 miles of range per charge.  With the Model S and Roadster, our range is at least double that (if not more) as we have ample access to really fast recharge rates with the Model S.

It is interesting to note that the majority of more EV mile percentages for the months occurred in the latter part of the year, when we had taken delivery of our two Teslas.  More importantly where both my wife and I had both driven predominantly EVs for our daily drive.  Whereas in the earlier part of the year, we only had the Active E and one of the ICE vehicles ended up being the other car driven.  As a whole, the household (as defined earlier) drove about 42,000 total miles.

Since, I’m an EV Geek.  I’m wondering what the next year will bring since we’ve given up our Active E and are both driving Teslas that give us at least 170 miles of range on a full charge.  I would hasten to guess that the percentage of EV use vs. ICE use should dramatically increase, but another year will let us know.  In the meantime, bask in the mediocrity of the past year.  [80/20, what a let-down.  Or should I really just celebrate verifying one of those rubrics that we’ve been taught since youth.]

[UPDATE 2014-06-15]Well, I guess I was NOT using my spreadsheet properly, I actually did not have an 80/20 first year, it was closer to 81/19… (or exactly 81.20% vs. 18.80%) It would seem that I forgot to calculate in the LAST month, fixed the calculations and it’s now correct.

EV Thanks on Thanksgiving 2013… 50,000 all electric miles!


So, my favorite EV News site at transportevolved.com asked what do you have to be EV Thankful for… (Interestingly they’re based in the UK, but with a LARGE audience of the American EV Community)

After over 21 months of EV driving and meticulous postings of my electric mileage, it’s finally happened. Sometime in the past few weeks I’ve passed 50,000 all electric miles of driving!

I would have been more precise, however. Sharing EVs with my wife, I can’t tell which are her driving miles versus my driving miles. I do know that I drive 95-98% of the time, so I can claim most of the miles.

So… What does that mean… Well, I’ve calculated a cost of approximately $0.008 per mile since I’ve moved to Solar power on my roof. Well, let’s assume that with the addition of the Tesla Roadster and Model S to the fleet, my costs have gone up to $0.012 per mile. I’m using this figure because both the Roadster and Model S exhibits more Vampire Drain (defined as the energy consumed by the EV while idle) than the Active E has in its approximately 48,000 miles of service. So, using this figure, let’s say that we’ve spent approximately $600 during these 50,000 miles. Well, I’ve used paid EV Charging Networks as well. Not too often, but enough to approximate an additonal $50, let’s double this figure to be really conservative. So, we’re talking $700 for the 50,000 miles. Now, if we had driven all those miles in our least expensive ICE (Internal Combustion Engine (gasoline engine)) car was at $0.15 per mile. These same miles would have been $7,500 in energy costs.

So, I guess after 50,000 miles, I have at least $6,800 to be thankful for.

What else do I have to be EV Thankful for… Frankly, living in Southern California has given me the ability to choose amongst the widest selection of Electric and Plug-in Hybrid vehicles on the market. I’ve been lucky enough to have been able to drive this gallery of electric vehicles.

Ranging from failures like the Coda (which I reviewed early on the blog’s existence) and Fisker Karma.

Coda
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Fisker Karma
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To California Compliance limited production run EVs such as the Honda Fit EV and Fiat 500e.

Honda Fit EV
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Fiat 500E
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Is the Spark EV a compliance car or production?

Chevy Spark EV
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To hand converted beauties like the ZElectricbug.

ZElectric Bug #1
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To full production EVs, like the Mitsubishi iMiEV, Ford Focus EV, Nissan Leaf, Smart 3rd Gen ED, and my latest temptation the BMW i3. Not pictured are the Chevy Volt, 2nd Gen Toyota RAV4 EV, and the Plug-in Prius.

Mitsubishi iMiEV
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Ford Focus EV
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Nissan Leaf
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Smart 3rd Gen ED
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BMW i3
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And of course, our EV fleet… The Tesla Roadster, Tesla Model S, and the one that got me hooked on EVs our BMW Active E.

Our Tesla Roadster
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Our Model S
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Our BMW ActiveE
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So… EVeryone in the EV world. From rEVolutionaries and those that are curious (join us, the water is fine)

Happy Thanksgiving!

The early Lakers exit and the Councours de Claremont 2013

So… I’m still stinging form the early Lakers exit this year.

However, this blog is about my ActiveE, EVs, etc.

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So, what do the Lakers exit and my ActiveE have to do with each other… Well, this year I decided to do some EVangelizing at my Alma Mater’s 2013 Concours de Claremont. It was held during Alumni Weekend in early May and I thought to join them on the field to display our cars. As you can see from the picture above, there were not so many of us this year, especially compared to last year’s attendance. The event was also sparsely attended this year. Perhaps it has to do with the weather as it was more overcast and rain threatened all weekend.

These stationary sort of car shows are fun, but I think the Plug in Day events are better. Really, the EV smile only clicks in AFTER someone drives an EV and it’s harder on stationary shows.

Here’s a nicer shot of my ActiveE beside a very clean jaguar and Porsche.

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Still the only EV at this event. Next year, I plan on attending with a Tesla Model S, unless I can be convinced that the i3 aesthetics aren’t nearly as bad as I think they are.

Here’s a nice picture of my neighbor, the ICE Jag… He really has such a clean engine.

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One of the benefits of an early Lakers exit from the playoffs was the fact that I was able to spend the entire show on the premises, last year I had to take off early to catch the game at 12:30pm. I got to meet and talk to some of the students, alumni, and faculty and explain why they should look at EVs for their vehicles. I also got to meet a fellow member of the Electronut family. A Freshman at the school’s father is a fellow alumnus and he, the son, stopped by to say “hi.”

If you’ll notice, I again plugged the car in at 120V as the school is just over 50% charge to get to and I figure at slow speed, it just gave me that much more juice to ensure that I got home for a half-day’s slow charge. However, it is important to note that my alma mater actually installed several Blink Network chargers not too far from the field that we were using for the show. I just don’t like to pay for public charging if I don’t need to. This is definitely a BIG improvement over last year, so I should at least praise them for providing the facilities, should I need to use them. Additionally, these pay chargers are cheaper than the ones on Chargepoint at the Pomona College location (on a per hour basis).

The dangers of high mileage EV use… Battery replacement!

One of the folks that I like to read often is Tom Moloughney’s blog (Aka Electronaut One) and he’s been writing about Battery Capacity loss and giving some hints on how to help mitigate it. As many readers know, it would seem that I am one of the higher mileage Active E drivers. I’m currently a little over 30,000 miles in a little over 14 months. And I find it hard to follow some of his advice as I tend to have to drive the mileage that I do and can’t really get to where I’m going comfortably if I decide to only charge to 80% SOC, so… I don’t. Regardless, the dangers of high mileage EV use is Battery Replacement! So at a little over 30,000 miles these past 14 months and change on the EV portion of my hybrid garage.

Some of the things to consider as we’re nearing the second month of samples of my Volt inspired sample of my hybrid garage. In my initial month, I did approximately 85% Electric vs. 15% Gasoline. This past month so far, I’m closer to 70% Electric vs. 30% Gasoline and a lot of that was because I decided to be a little more Rage Sane than Range Insane to my drive to Morro Bay.

Regardless. If folks decide to look deeper into my samples, they would notice that I haven’t driven my approximately $0.20 to $0.25 per mile BMW X5. This was originally because of choice than anything else. I didn’t really need to haul anything larger, pick anyone up at the airport with lots of luggage, or just feel “bigger” than the rest of traffic. So, the car sat at the garage. Well. It’s a nearly 12 year old car. A couple of weeks ago, I figured to start it… And Lo and Behold, it wouldn’t start. The battery was dead. The last time I bought a battery was less than six years ago, but one of the dangers of running a hybrid garage is IGNORING your ICE vehicles. Granted, this was the same challenge when my HOV capable vehicle was a Honda Hybrid Civic. But that car was not nearly as fun to drive as ANY of my BMWs. So, I drove the X5 a little more than we do now.

The Morro Bay drive went convertible top because the weather was ideal for it. We could have easily spent more money and gone with the X5 because we were headed into Santa Barbara and Central Coast Wine Country and could’ve opted to have space for a few cases, comfortably.

Regardless, the battery died. It had to be replaced. Luckily, the last replacement still had nine months left on its warranty and we got a 9/72 partial refund on the older battery to make our replacement approximately $120 after taxes. Basically the refund covered $17 of a totally brand new battery.

This experience has gotten me thinking of Tom’s write up and battery replacement in general. Tesla has just released an enhancement to its service and repair program that includes an enhancement to the coverage of the battery pack. They’ve already spelled out the cost for the 60 KwH and the 85 KwH battery packs ($8,000 and $12,000 respectively, I believe.) The Nissan Leaf’s battery capacity warranty has been spelled out in terms of what to expect over time and mileage I believe. i.e. 80% SOC on year 5 or something like that.

BMW i needs to do the same thing for the battery packs for the i3 and i8 when the cars are released or even slightly before the release of the car. As Tom champions, I second the motion. Potential purchasers of the i3 (of which I continue to hold on to hope that our second EV will be, though that Fiat 500e sure looks aesthetically pleasing to me… even though the Fiat does remind me of a gumdrop, but I digress,) will need to be able to compare EVs to each other. However as the aforementioned Tom Moloughney wrote, the Fiat 500e and the i3’s battery systems are identical, so I don’t really need to compare these specific cars (unless there’s a change in how each company regulates the temperature of each vehicle.) for what the expected battery loss figures would be. It’s not just EVs that lose capacity/capability as it ages, ICE cars also lose power as the cars age. That’s just entropy in action. It’s just front and center to EVs. I don’t necessarily like to lease my cars, regardless of what fuel motivates it. I would much rather own it outright and just pay for the things that keep it moving.

So, barring such information on battery replacement from most manufacturers, it would just be the responsible thing to do to put away some of the “gasoline savings” aside into a fund for a rainy day. Whether one save approximately $10,000 (the figure between the two Model S published numbers) or less is entirely dependent on the EV owner’s resources and ability to save. I think that it is prudent to put aside half of what a future EV buyer saves on gasoline toward purchasing a replacement battery pack in the future. I didn’t come to this number through ANY analytical means, just a guess, if you will.

Minimizing gas use…

So, about a month ago I was inspired by an article, on Plugincars.com regarding BMW’s plan to allow i3 drivers the ability to rent a traditional gas (internal combustion engine/ICE) BMW when they need it, to figure out how often my family uses ICE vs. EV.

Seeing that there are two of us who use vehicles in the family, I figured to count the FAMILY’s usage of Gas vs. Electric.

So, I decided to log my mileage of use for the period between March 6 and April 5, 2013. It was a rather interesting log. We travelled a total of 2,948 miles in this period of which we did 2,499 miles Electric vs. 449 miles on gasoline. I anticipated a heavier gasoline use this past month as we were going to help our nephew move. Ended up not using the X5 for this and he only needed a few items which fit our ActiveE, so, score 1 for the EV use.

However, as things do tend to go to the mean, the 328i ended up with a recall. Of all things, in the electric wiring of the vehicle. As a result, had to do almost 100 of those miles gasoline and 22 of the approximately 100 miles was using a 5 series loaner.

Good thing the BMW ActiveE folks were not planning on the Morro Bay FB meetup until tomorrow, otherwise, I would be adding another 460 miles on gas as I’m not crazy enough to wait the hours needed to charge the Active E on the drive north and south to the meet.

Hats off to some of my fellow electronauts who live a fully electric life, I’m not sure if I can quite do that yet.

These brave souls all live fully electric, or at least nearly so – check out the blogs of Todd Crook, Peter Norby, and Pamela Thwaite

Todd is impressive because the whole family uses the ActiveE, solely! Peter has both an ActiveE and a Honda Fit EV, and Pamela Thwaite‘s family has 3 Electric cars. A Tesla (roadster, I believe), Active E, and a Mitsubishi iMiev for the kids.

Still, at 85% electric vs. 15% gasoline. I think I’m doing well… Saving a lot of money and enjoying the ride!  Figuring that my 2499 electric miles is closer to $21.64 and my 449 miles of gasoline is closer to $85 (using an inflated approximate $0.19 per mile as I do not have the cost per mile for the 5 series vs. my $0.17 per mile calculated convertible 328i cost.)  If I were to extend $0.17 per mile to the 2499 electric miles, I’m saving about $400 on not buying gas.  (not even factoring in $100/hour per the currently controversial articles on Tesla’s leasing program.)

When we get a Tesla Model S (unless BMW comes out with a more aesthetically pleasing i3 or cheaper i8 BEV, not hybrid) and with that range, we would probably not need to drive as much gas as we do now.

Some significant mileage… 25,000 Miles and counting…

ActiveE by dennis_p
ActiveE, a photo by dennis_p on Flickr.

Reached 25,000 Miles a few days ago… Seeing that my one year anniversary will be in a few weeks I figure to write more about my experience then.In the meantime.

25,000 miles all electric. Using a blended 1.5 cents per mile figure (just estimating here since it’s closer to 0.8 cents per mile since I’ve gotten solar at home) nets me a $375.00 energy cost for the 25,000 miles. Comparing this with an estimated 15 cents per mile for gasoline (rounding down ’cause it’s easier to do the math…) puts the estimated mileage cost to $3,750.

So looks like we’ve at least saved $3,375 this past year on the miles that we used electricity vs. gasoline.

The savings are compelling.

More Napkin math, OR – Real Goods Solar and BMW’s program is a REAL GOOD deal!

Saving money while saving the environment is an addictive process.  It’s crack for good Karma!  I feel like Michael Corleone in the Godfather III, I try to get away from it, but they keep dragging me back in!

As I had indicated on my Ping! post, I got “unofficial” Permission to Operate (PTO) on August 17, 2012 and finally received official PTO ten days later on August 27, 2012.

So, we’re now running our car on Solar Power…  or are we?  Unless your house is completely disconnected from the electric grid, what you are really doing is netting out generated power from the solar panels on the roof with consumed power from the electric grid.  So, if you’re overproducing power from your solar panels than what you’re consuming, you get money back, otherwise you’re really just netting out what you’ve made with what you’ve used.  As I have published previously, the rate to charge depends a lot on what tariff you’ve chosen.

In my first napkin math post, I charged on the SCE Domestic rate which effectively got me charged at $0.31 per kWh as my usage of electricity had already pushed me to Tier 5 for most of the billing periods.  In order to normalize and compare ICE vs Electric, I calculated that the cost under the first plan was 1.714¢ per mile

By my third napkin math post, I attempt to alleviate that $0.31 per kWh charge by opting for the whole house SCE Electric TOU Tiered rate structure, this pretty much reduced my rate to charge to $0.13 per kWh for my car charging needs (as well as my pool pump as I switched the time of use for that from mid-day to mid-night to 6 am).  As we noted on that post, my cost per mile dropped to about 1.412¢ per mile.

So, the big question is what is my cost per mile under the Real Goods Solar and BMW ActiveE program deal.

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Before I took advantage of this deal, I would like to tell you about my search to save our energy costs further.  Not necessarily the environment, but that’s always a fun side-effect with this accidental environmentalism that I’ve stumbled across.  After signing up for the Active E, I figured to become educated on what my solar options were.  To that end I requested quotes from three solar companies in the Los Angeles County area: Peak Power Solutions (Sunpower reseller), Solar City, and Verengo Solar.  Each solution had its strengths and weaknesses and around the third week of March (between three to four weeks of receiving my ActiveE), I decided to sign a power purchase agreement with Solar City.

A power purchase agreement is basically the right to buy a guaranteed amount of power from a provider for twenty years.  I don’t own the solar array on my roof, someone else does (a finance company) and I agree to pay them a fee for this.  This means at the end of twenty years I get the option to keep buying from them, buy the equipment outright, or have them remove the array from my roof.

So, how did I compare the suppliers.  Ultimately, economics.  So, at the end the Solar City deal that I had originally signed was approximately $0.10344 per kWh.  How did I calculate this?  All the suppliers with the power purchase agreements have a guaranteed rate of production for the 20 years that the system will be produced, so I divided the total guaranteed kWh by the the total prepaid lease amount, and that’s how I got to the $0.10344 per kWh.

So, I thought that was it.  I signed up with Solar City, got a rate that I felt was fair and waited to get installed.  Solar City’s installation process was methodological and professional.  They provided a website to track the progress of the installation and was quite impressive.  However, their process proved to be the opportunity for Real Goods Solar and BMW’s deal to come in and make my costs even less.  Around the beginning of May, during the design and survey process, Solar City notified me that in order to proceed with the installation of the system that I signed in the third week of March (about five to six weeks earlier) my roof would have to be replaced.  This change provided me with an out-clause from completing the agreement that I signed with Solar City.

As I was mulling through a roof quote and setting up more roofers to see what this replacement roof would cost me, Real Goods Solar and the BMW Active E program announced their program.  So, I figured, why not ask them to see what the solution would cost me.  I contacted Real Goods and they had a sales agent contact me within the day.  Their initial quote was 12% less than the Solar City quote and agreement that I went with.  However, I had to bundle in the cost of the replacement roof and needed to get the total project cost to figure out which deal I was going to take.

Figuring that both solar companies would probably be able to get a reliable, professional, licensed roofer at a lower cost than I would have on my own, I went back to both providers to find out what the roof was going to cost from them and go from there.  My assumption was not exactly correct as my independent roofer quote was actually $500 to $1000 cheaper than the lowest quote from either solar provider.  I was at an inflection point.  I was already saving quite a bit on gasoline with the TOU tariff and this would have been the time to quit or cut bait.  I approached both providers to see if there was anything they can do to their quote to make the entire project less expensive (replacement roof and solar).

The dilemma is how do I adequately calculate my cost per kWh based on the various scenarios.  I figured the most conservative thing to do would be to subtract the lowest roofing quote from my total project cost and use that figure to divide my cost per kWh over the guaranteed generation over the life of the system.  Granted, this methodology would provide me with an understatement of cost as the guaranteed rate of production is typically rather conservative of the suppliers, but it IS what they guarantee, that is why I went with that methodology.  When the system has really sunny days it will outperform this guarantee and my actual cost per kWh is less than what I calculated.

With the total system cost, I figure that my cost per kWh is $0.10250, however, if I subtract the roof cost my cost per kWh drops to $0.07970 based on guaranteed power.  Seeing that my energy cost is a 38.7% reduction, mathematically speaking, my cost per mile is approximately .8657¢ per mile ($0.008657) or 73.58 cents per day based on the 85 mile day that I had in the last post on this matter.  Not bad at all.  Of course, the system is currently overproducing and with time of use I actually am paid a rate for the energy I am sending back to the grid during the day and most of my charging occurs between midnight and 6 am, so this is, like my other estimates “napkin math”, so I am certain my actual costs are lower, but the numbers work for me.  Remember, my original calculation of a comparable vehicle costs were approximately 17 cents per mile, so my 0.8657 cents per mile cost is quite a bit less than driving my ICE 328i convertible.

So, there you have it.  My energy costs are a heck of a lot less than it has been.

Want to see what my system is producing, check out the sidebar production information courtesy of Ken Clifton‘s plugin for WordPress or directly from Enlighten’s website.

In a few days, I will follow up this Napkin Math article with pictures and my opinion on the installation from Real Goods.  Let me just say, I recommend them and if you give my name, I get a referral on your system, so contact me if you’re serious and I will recommend them.

Interested in going solar? Get a quote from my solar vendor – Real Goods Solar.

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Ping…

Yes,  I’m still here.

I’ve been busy with our ActiveE and have been on vacation on top of that…  I promise at least two more ChargeIt! articles for two really great food AND charging facilities (here’s one of them – Gjelina at Electric Avenue in Venice). [Here’s the other Church and State – Mateo Street Charger, now caught up for the Great Food series.]  However, trying to decide on whether to do the next article on joining the Solar powered movement.

Still haven’t received my “official” PTO, but I did notice an off-cycle close to my SCE account this past Friday (August 17) (when I logged in to my SCE account on Saturday) and followed up with a call to SCE on Saturday morning.  According to the telephone representative my permission to operate (PTO) letter went out last week and I am now generating my own energy via the Solar Panels on the roof of the house.

Thanks to BMW and its partnership with Real Goods Solar, I was able to get a system at a bigger discount than I had originally negotiated with Solar City.  But that will have to be the subject of a subsequent post.  As well as updates to my Back of the Napkin Math series (1) and (2).

As those that have followed this blog, I’m not an “environmentalist”, I just like to save money.  As long as one has a “long” view, the money savings will follow those that do things that are “environmental.”