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BMW i3 Driving to Net Zero Energy – Powered By Sunshine – Month 4 Update

3 years ago by Peder Norby 13

Driving To Net Zero Energy

Driving To Net Zero Energy

Update Month Four, Still Adding To The Bill Credit!

The idea is a simple one, harvest endless sunshine from a small portion of a roof to provide 100% of the energy needed to power a home and two cars with zero utility cost, and zero gasoline cost.

The beginning, almost 6 years ago with the Mini-E and our Sungas Station.

The beginning, almost 6 years ago with the Mini-E and our Sungas Station.

We continue to amass a large credit on our annual energy bill, more on that below.

As we begin the fifth month of the “Driving To Net Zero” energy challenge, I’m reflecting on the beginning of our transition from two gas cars to two electric cars powered by solar.

The Solar PV on our house was first when we built our home in 2006. Then came the 2008 Mini-E and the fascination about the potential to provide the electricity required by the electric Mini-E from the roof of our home.

Will it work? will it go up hills? will the batteries be unreliable? will it be like a golf cart and begin to slow down on the final four holes? Will it be a toy or will it be reliable transportation? Will it be boring? Will the headlights dim like a flashlight running out of juice? Will it start when I push the button? Can the sun make enough energy via Solar PV to power the car? Will my garage blow a fuse or worse? Will I be considered a dork in a play car not a real car?

*Editor’s Note: This post appears on Peder’s blog.  Check it out here.

We kept our two gas cars as we were unsure the electric Mini-E would work for us. We simply didn’t trust it, however it was experiment that we were eager to try.

We loved our time with the Mini-E # 187 like no other car before. The Mini-E worked beautifully as fun and dependable transportation, far beyond our expectations. After three or four months of not using the other gas car at all, we sold the gas car and became a one electric – one gas car family.

Two and a half years and 35,000 sunshine powered miles went by fast in the Mini-E. As I was preparing to transition into “my” second pre-production car the BMW ActiveE, an unexpected and surprising event occurred. My wife Julie claimed dibs on the ActiveE. I decided very quickly it was better for me to drive a gas car and be happily married and let her drive the ActiveE than insist upon driving the ActiveE. I was miserable for several months wanting to get back into an electric car.

After Julie drove the ActiveE for a year without needing a gas car, we then knew that neither one of us needed a gas car and we transitioned to two electric cars. First the BMWActiveE and the Honda Fit EV en-route to our current garage filled with two BMW i3’s.

That’s the short version of a very long transition from interest but skeptical, to amazed and excited about transitioning to EV’s.

From where we are now having completed that transition, it’s almost humorous to think about our concerns from several years ago, if one electric car would work even if we kept the two gas cars. Yet that was exactly our concern and is a concerned shared by most who are thinking about beginning their own personal transition from gas to electric. For most, similar to our experience, it will be an evolutionary change with many steps as compared to a revolutionary process. The inertia of the status quo (gas) is strong and difficult to change.

So how are we doing in the Driving To Net Zero Energy Challenge, living in a solar powered house and driving two cars a total of 24,000 miles for a year?

We’re a third of the way through the year with a little over 9000 on the i3’s. We’re still generating more energy than we use although that will change soon as we get into the winter months, we hope to catch back up and get to zero net usage in the sunnier months of March April and May.

Energy Graph

Energy Graph

Last month we saw a large uptick in the amount of energy we used primarily from driving our French exchange student everywhere and the cooling of our underground wine cellar during a very hot month. The good news was that our solar PV generation was also high.

How can we use 117 kwh for the month and have a $132 credit you may ask? Simply because energy is cheap at night and expensive during peak hours. Energy is priced $0.49 per kWh during the hours when we produce extra and $0.16 to $0.20 per kWh during the times when we use electricity from the grid, thus a credit. You can see when we generate or use energy in the chart below.

Net Energy Metering Chart

Although the challenge began in May, we will be below zero in cost with our true up bill in January. We are currently about $445 ahead for the year with just a few months remaining.

A very good month for solar PV.

A very good month for solar PV.

We used 605 kWh to drive 2860 miles last month. We had5 DC fast charging experiences (approximately 80kWh in total) as we were driving further away from home-base during the month.

We used 605 kWh to drive 2860 miles last month. We had5 DC fast charging
experiences (approximately 80kWh in total) as we were driving further away
from home-base during the month.

One last thought for this month. The air that we breath is not our private property. The air that we breath is part of the “great commons” shared by all that inhabit our planet. Our cars and their emissions are our personal property. We should and must be concerned about the health of our commons and our role as private citizens in making them better, or making them worse.

Thanks for reading and commenting. Many more topics to cover in the coming months.

(Past “Driving To Net Zero” articles)

Energy Challenge Introductory Article
Mid Month Article: The Energy Grid
Update Month 1
Mid Month Article: Does your Gas Station Pay you to fill’er up?
Update Month 2

Update Month 3

*Editor’s Note: Peder is the Chairman of the San Diego County Planning Commission. His wife Julie is Director of Curriculum and Instruction at the Solana Beach School District. They have been Field Trial drivers for BMW for five years. Together since 2009, they have driven 100,000 EV miles powered from roof top solar.

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13 responses to "BMW i3 Driving to Net Zero Energy – Powered By Sunshine – Month 4 Update"

  1. leaf owner says:

    Interesting – but clearly has too much time on his hands!

  2. jm says:

    Thanks for the update, Peder, appreciate the detail! Your narratives was the final inspiration I needed to order a i3 BEV due in end of next month. Off topic question: what’s the farthest you’ve driven on one charge and under what driving conditions? I have a similar climate to yours here in HI and am installing 5-6 more panels to power the i3. Thanks

    1. Peder says:

      I have done 114 miles on one charge with three miles left in city driving on Hwy 101 between Oceanside and La Jolla. Speeds were between 25mph and 50mph.

      Normal mix of city at 35pph and highway at 70mph figure around 85 miles, and all highway driving at 70mph figure around 70 miles.

      So far we are averaging about 4.5 miles per kWh. At 12,000 mile a year that’s around 2666 kWhs. An 8 panel, 2kw system will generate 3100kWh here in San Diego. On a kWh basis it would be about 6 or 7 panels to provide the same Kwh as the i3 uses. On a cost basis due to the benefit of Time of Use pricing, around 5-6 panels.

    2. vince says:

      Hi jm. I have just done 3600 miles in my i3 in UK including several records for stuff. I have not charged using solar power – I live in Cambridge England and although we had a glorious Summer and Autumn this year, it usually rains mostly. The run was for charity but although I have a small collection of great classic BMWs I just love the i3 to bits and drive it everywhere. See the blog site – thegreatnorthhum.wordpress.com – for Louise’s take on the main part of the journey. So glad it has a Range Extender as you will learn from the blog! Vince

  3. vadik_veselovsky says:

    Detail is what counts, way to go, Peder!

  4. wraithnot says:

    I have a quick question about the consumption values for the two cars: do you have a separate meter for each EVSE, are do you get the information from the cars themselves? If you are getting the data from the cars themselves, do you reset the trip computer every month to get month-by-month values?

  5. Peder says:

    Yes, thanks for the question.
    Chargepoint was kind enough to support our effort by loaning us a commercial ct4000 dual head charger so that we could data log each car. Julie uses her chargepoint card on her side of the charger and I use my chargepoint card on my side of the charge. You can then monitor each plug and/or you can monitor the station which includes both plugs.
    The bar graph included in the story is the station usage of 605kWh which includes both plugs. The data graph in the story has each plug separated out.
    Thank you again to the chargepoint team for helping us out in this effort as the ability to view and collect accurate data from charging the car is really important in our effort to document our energy use and consumption.
    I’ve also learned that the BMW draws very little extra from the wall as compared to a lot of cars with heavy ghost loads and that Julie is a far more efficient driver than I am! I love the quick acceleration!

    1. Wraithnot says:

      Thanks for the info. Since I don’t plan on buying charge point EVSEs, I’ll have to figure out some other way to log data from our new i3.

  6. Peder says:

    no on the trip computer. We simply take a reading at the end of the month and subtract the prior month cumulative total.
    Cheers!

  7. Spec9 says:

    I just had my annual “True up” with PG&E. I generated some 4.5 megawatt-hours more than I used. This includes my EV charging. So I paid nothing for gasoline, nothing for electricity, and they paid me some $207. (A credit that will lower my natural gas bill.)

    I need to get around to insulating my house and sealing it up so I can now slash my natural gas usage. And I’m toying with the idea of doing a solar hot water project.

    1. Peder says:

      Great to hear, it’s amazing how much one can save in gasoline and electricity cost and how fast it can pay off after the initial investment.

  8. Brian says:

    Thanks for the update, Peder. I always enjoy reading about your journey. Our climate is not so conducive to being net-zero, but I still try to do my part.

    The past 4 months are among the best for solar (although my best month every year seems to be May), I can’t wait to see how the winter treats you, and whether you can meet your 12-month net zero goal. I’ll certainly be rooting for you!

  9. Phr3d says:

    What a wonderful world — the ‘valley’ can now solve one of its big ongoing problems, and might even do so at a decent gain to its constituents. Initial invest is kinda’ tough, but a refi could increase your income by x-dollars per year. Is the solar savings from the re-fi ‘investment’ in solar enough (~$100/mo?) to cover the ‘extra’ payments on a shiny new EV? Now no fossil expense for travel (and minimal maintenance), and that adds up to a total of? (fossil – possibly overnight electricity = almost certainly positive monthly cash flow if refi house payment remains static)

    If the ~$100/mo solar-income increase can be realized, welcome to Electric, CA.

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