Two BMW i3s, One Sun, Zero Gas


Zero Cost of Energy and Gasoline for a Year

*Editor’s Note: InsideEVs has documented Peder Norby’s journey since Day 1.  This post is the month 8 update in a year-long series in which the Norby household attempts the near-impossible.  The basic idea is simple: Can we harvest endless sunshine from a small portion of a roof to provide 100% of the energy needed to power a home and two cars (a pair of BMW i3s) with zero utility cost, and zero gasoline cost for 12 months?  Read on to find out.

We’re popping the first bottle of champagne as we have now documented a whole year with no cost of energy and no cost of gasoline to power a home and drive two EV’s a collective 20,000 (actual 24,350) miles a year.

How we use our BMW i3 Frunk. Champagne and Shrimp on ice!

How we use our BMW i3 Frunk. Champagne and Shrimp on ice!

We’re not done yet as we still have four months to go on our effort to get to Net Zero energy, as well as zero cost. More on that at the end of this post.

Today, we affirmatively answer this question: Can we 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 for 12 months.


Driving To Net Zero Energy Challenge

Driving To Net Zero Energy Challenge

Peder's BMW i3 Enjoying The Wilderness

Peder’s BMW i3 Enjoying The Wilderness

It’s possible that this feat has been accomplished before. We are not aware of any documented effort by any household in the world, where from a small portion of a roof, sunshine is harvested to provide 100% of the energy needed to power a home and two cars with zero utility cost and zero gasoline.

We believe, we are unmistakably on a transitional path to renewable energy and electric transportation, a path as predictable and reliable as the sun rising from the east, racing though the heavens, and setting in the west.

We are living at a time of one of the biggest changes in the history of humans on earth and we are all active participants in this evolutionary change towards renewables for energy and transportation. A change that brings with it; healthier air, cleaner water, richer families and communities, energy equity and a premium quality of life.  Driving is faster, quicker, quieter, less jerky, more enjoyable, and yes, it puts a big fat grin on your face every time you do a 0-60, 6.5 second sprint in the BMW i3.

Think about it for a second, the “future is today” whereby we can provide the energy for our cars  and our homes by harvesting sunshine on our roof.

It is indeed a new day, and to borrow the words from BMWi: Hello Future

Harvesting coastal breezes to cool our home, partnering with nature.

Harvesting coastal breezes to cool our home, partnering with nature.

The three foundational pillars in our Drive to Net Zero are:

1. Building a very efficient home. Harvesting passive solar for heat, wind for cooling, rain for growing both drink and food.

2. Our two BMW i3’s, the most energy efficient car sold in the USA at 124 mpge.

3. Harvesting the sunshine falling on our rooftop  to power our home and cars.

On January 19th 2015, we received our “Annual True-Up” bill from our utility, SDG&E.

We had a $434.57 credit at the end of the year

We had a $434.57 credit at the end of the year

 This bill will be common in many states in just a few short years.

This bill will be common in many states in just a few short years.

Gas Meter Reads

Gas Meter Reads

Highlights from our annual bill.

Our annual electricity cost for our home and cars, $-36.68
Our credit for unused electricity, $-434.57
Our annual gasoline cost for two cars, 24,350 miles, $0.00
Our natural gas cost, $279.89

Our total cost of energy for the year $-191.36

Interesting Tidbits:

We had anticipated getting to zero cost in May of 2015. However the efficiency of the BMW i3’s reduced our energy use far more than we thought, so we accomplished the goal five months early. For the first five months of the year, we were driving a BMW ActiveE EV and a Honda Fit EV. The i3’s were delivered in late May.

Our two BMW i3’s use 6000 kWh of electricity annually, an average of 3000 kWh for 12,000 miles each, 24,350 mile total. We have had no gasoline cars during the year.

Our home uses 7500 kWh per year. Our home consist of a main house of 3300 sq. ft. occupied by three, and a guest house of 1200 sq. ft. occupied by two. It’s essentially two homes with two families on one utility meter.

Our solar 8.5kw PV system, installed in 2007, was paid off in April of 2012 with the utility and gasoline avoidance savings.

Our annual savings on utility cost and gasoline cost is $8,500

We have reduced our CO2 emissions by 30 tons annually.

Future goals.

To have zero carbon footprint.

We have reduced our household carbon footprint to 2 tons per year according the EPA carbon calculator; the remaining carbon is due mostly to our small natural gas use. The national average is 40 tons per household.

To offset our generation of carbon, we have donated a brand new 9kw solar PV system to our local lagoon foundation. This solar PV system offsets approximately 13 tons of carbon a year. We are net carbon neutral.

The next four months:

Four months to go, can we get to negative kWh?

Four months to go, can we get to negative kWh?

We began this “Drive to Net Zero”  in May of 2015 with two goals. The first and largest one was to zero cost.  The second and perhaps harder to attain, to be net zero energy. We have four more months to go, are we going to make it?

It looks to be close.  Next month we will add a couple of hundred more kWh to the total and then the following three months we will reduce the total.

What makes this challenge interesting, is that it is real world with a real family, not some theoretical exercise, on some “super house” on a university campus with a non existent family, substituted with a computer tabulation of static energy use over a year, including one compliance car which you can no longer buy or lease.

Life is not static, it’s dynamic, wonderful and ever changing.  

In our case we have had a few unplanned for events over the past eight months that have added a few thousand kWh to our “normal living” usage.

1. We’re hosting a 17 year old French Rotary exchange student for the year.  You should see her hair!  Anyone care to calculate how many kWh per year 20 minutes of blowdrying 7 days a week uses? Not to mention lights, computers TV and more. We love her and she is having a great experience in the USA.

2. It’s my year as Chairman of the San Diego County Planning Commission. What was  typically 3-4 long drives a month is this year 12-15 long drives a month as chair.

3. Family illness and the loss of a loved one.  We said goodbye to a family member and another had a major surgery a month before.   This created many many long trips to the hospital and to my siblings over the course of a few months.    The family is strong and it was a blessing.  Getting back to cars, the BMW i3 did great handling all the unexpected and longer trips and we made use of the DC fast chargers at Fashion Valley and downtown San Diego during this time.

We are putting on about 5000 miles extra on our i3’s over what we planned for and what is typical for us.

BMW i8s Ready For Delivery

BMW i8s Ready For Delivery

I think were going to be plus or minus around 500 kWh for the year.

About that BMW i8…

Owning a “First Vintage” of both the BMW i3 and the BMW i8, is a scrapbook of a personal journey of our several year relationship with BMW from the “Mini-E and a dream for the future,” to today with both cars, a BMW i3 and BMW i8, a reality.

Our plan is to keep the BMW i8 as a very low miles collectable car and we will keep both of the BMW i3’s as our daily drivers.   It’s sort of our own version of a flexible mobility program.

With two BMW i3’s  we would borrow or rent a long haul gasoline car once or twice a year for a trip to Napa, now we’ll take the i8.  It’s also going to be a great out to dinner car driving electric only to our local restaurants.

We plan to remain a two EV family, with our own flexible mobility plan. Yes, I’ll lose my EV purity card 🙂

It takes six to eight solar panels to power a car 12,000 miles a year for 30 years

It takes six to eight solar panels to power a car 12,000 miles a year for 30 years

Thanks for reading, and if you can remember one thing and one thing only, remember this:

Sunshine is a transportation fuel.


(Past “Driving To Net Zero” articles)

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 more than 100,000 EV miles powered from roof top solar.

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32 Comments on "Two BMW i3s, One Sun, Zero Gas"

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Congratulation Peder!

This is an important achievement indeed. Quite gratifying too. 🙂

Let’s hope many others become as dedicated and as fortunate as you have.

Yes, love to see these kind of posts.
Was the house designed net-zero or did they modify?
And what modifications?

” in which the Norby household attempts the near-impossible”

A bit over dramatized, dontcha think? BTW, I did this last year . . . Entire house & EV net electricity generated by solar and PG&E ended up owing me $204. (That $204 credit has covered some my natural gas usage this year.)

Good job Peder, I applaud your efforts.

But as I’ve pointed out before, as long as you’re using natural gas, you’re not “zero net energy”, you’re “zero net bill”.

There is a difference.

Also, it occurred to me that our own attempts are difficult to do because with two young drivers in the house (18 and 22 next week), it would also require that they drive EVs which they can’t afford.

This is something that is often overlooked in the efficiency drive (and that Peder has eluded to) – teenagers REALLY complicate the process of reducing energy usage.

Hey Peder-

Wondering if you’d care to wax poetic about the future of heating/dryers/stoves in an upcoming era of cheaper solar.

We have a Chevy Volt, drove 9,000 miles last year, and had over $1k in credit with PGE. Which made me think… what if I could do some of our heating with that electricity instead of gas? I get that gas is way better cost-wise for heat, but if I have extra….

Think we’ll ever get to a hybrid gas/electric heat or combined gas/electric dryer system where it’s ‘smart’ and knows when to use up your ‘extra’ electricity and when to use gas?

A hybrid-electric water heater is an easy install if you can get the electricity to the water heater location. I don’t like the “hybrid” name because it’s an all-electric combination of heat pump and resistance heating, not electric + fossil.

Changing from gas to an electric clothes dryer is another easy way to use up surplus solar electricity.

Mike – do you mean a heat exchanger electric water heater?

+1 on that, I’ve been looking into it.

Whereas an electric on demand water heaters is 99% efficient, the heat exchangers are like 300% percent efficient (google for an answer on how that works).

The problem is, now that we have a smart meter, I can see that the showers with the on demand heater really aren’t using/costing that much (yes, even with the teenagers).

I think most of our power usage comes from laundry (running constantly it seems) and oven/stoves.

Yeah, I’m sorta in the same boat. It would be an interesting project to try to eliminate the natural gas usage.

But the natural gas is pretty cheap and it is a very big investment to try to eliminate it with a heat pump.

I personally think Natural Gas is going to spike in price soon. This due to the power conpanies building 1000 megawatt gas fired power plants by the dozen this year. My local power company has gone on a natural gas power building boom. This natural gas building boom is them trying to shut down all the coal fired power plants with gas.

My mom had a solar clothes dryer way back in the 1960’s. Although I must say, it was a bit embarrassing that all my neighbors could see my tighty whities flapping in the breeze. 🙂

And seems like those are always part of a scary scene in a horror movie.

BTW, I know people that still dry a lot of their clothes this way (in the US, it’s more common outside the US).

I was told it was even illegal(!) to dry your clothes like that in some US states. I hope it was just bad information.

Drying your clothes from the sun in the fresh air is so much better. The wear and tear of machine drying is just crazy.

My mom still likes to do clothesline drying because of fresh smell, habit, energy savings, etc. She was doing it at a retirement condo down in Florida and some people started to complain. So I dug up the Florida solar power rules that you can’t ban usage of solar power with such HOA restrictions such that their whining was moot.

I hate HOAs.

I’ve seen them ban solar planels saying that they take away from the natural looks of a home’s roof. Me personaly that is the look of my roof saving me from the power company cookie monster.

What’s cool is in several places the growing use of solar power on home roof tops is wreaking the coal and oil fired power plants The solar power growth is getting so powerful it’s shut down several natural gas plants in Germany.

Me personally I plan to get solar power as soon as I get my first place in that you can’t go wrong with something that protects you from the EPA and the power companies still thinking it’s the 1950’s with power.

“BMW i3′s, the most energy efficient car sold in the USA at 124 mpge.”

Anyone know what makes it more energy efficient than the Leaf? Weight, or what?

That it can travel a longer distance on less electricity makes it more efficient. 😉

Weight is a part of the answer, but it’s much more efficient than equally or even lower weight EV’s so it’s just a part of the equation. The skinny tires is a large part to the answer.
And the rest must be up to a more efficient drivetrain in general compared to the competition.

I like the finishing quote “Sunshine is a transportation fuel”. Also up here in the Pacific Northwest we unfortunately get less sun, but “water is fuel too.” The Columbia and Fraser rivers give us renewable electricity. In BC we pay $0.06/kWh for hydro power. That gets my Leaf about 100 miles per $1US. So we are also very fortunate to pay next to nothing to drive with no environmental impact. As EVs become more affordable and longer range, we need to spread this message everywhere to accelerate replacing ICEs with EVs.

I’m kind of late to the game here Peder. What happens when net metering goes away. We’ve already seen the push in Hawaii. For you, you’ve already paid off your panels, but for new installs with no access to net metering, How does this change?

Way to go and we are close behind you. We just purchased our 2nd plug-in, a Volt, in late December. Before that our solar with our EV were net positive. So it can be done with real families in real homes.