BMW i3 Driving to Net Zero Energy – Powered By Sunshine – Month 11 Update


Image Via Tom Moloughney

Image Via Tom Moloughney

Month 11, Harvesting America’s New “Gasoline”

Ubiquitous, equally available to all, zero emission, zero cost, powerful enough to provide the energy for all the cars in the country, and it will last forever. The only question is….

Will you harvest it?

There’s a popular phrase that says, “As goes California, so goes the rest of the nation” Perhaps a bit boastful, but in the automotive context; the pressures, regulations and trends, the forces that will shape the future of transportation in America, it rings absolutely true.

While most Americans only know of Solar PV as way to offset their home or business utility bill, Californian’s increasingly are becoming acutely aware that Solar PV’s highest and best use is as a transportation fuel.

Californians are harvesting sunshine to replace gasoline.

Solar PV is spreading faster than gasoline on fire…

According to the Center for Sustainable Energy and it’s last EV owners survey, 39% of California’s 125,000 plug in drivers (based on respondents to the survey) are making their own fuel on the rooftops and backyards of their homes with solar energy.   Surprisingly, the percentage of solar PV + EV combos over the years is growing not shrinking as more and more capable EV’s and PHEV’s come onto the market, and solar PV becomes more affordable and more attainable.

With an electric car, you can make your own fuel. Try making and refining gasoline on your rooftop and let me know how that works for you. I’d love to see a picture.

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

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Californian’s know that sunshine is a transportation fuel.

A fuel that when harvested is 1/10th the cost of gasoline, a fuel that when paired with an electric vehicle eliminates the largest source of emissions that American cities face. In many cities, emissions from gasoline and diesel powered transportation contribute to over 50% of the man made pollution in that city.

When a person in a city makes a decision to drive electric powered by renewable energy, each and every breath of air that we all share as a great “commons,” that we all inhale, becomes cleaner for all, and health related issues of air quality are improved for all.

Solar PV when used as a utility offset is good. Solar PV when used as transportation fuel is an enabler of financial savings and family wealth building due to tremendous gains in efficiency.

How, Why, What’s the difference?

Solar PV when used to power the home, powers the same appliances, light fixtures and electronic devices that the utility supplied energy powers. These appliances and devices are no more or less efficient whether powered by solar or utility supplied electricity. Solar may be less expensive with zero emissions, but there is no inherent efficiency savings for the devices and appliances it powers.

Solar PV when powering a car enables an efficiency savings of between 300% and 400% as compared to gasoline powering a car.   Simply stated, a gasoline car will go 25 miles on average, and an electric car will go 100 miles on average using the same amount of energy.  Said another way, the electric motor is 3 to 4 times as efficient as a gasoline engine in converting energy to power the wheels.

In large measure because of these efficiency gains, the economic return of sunshine being harvested as a transportation fuel, is twice as great as when it is used as a utility offset to power a home or business. Even greater is the environmental benefits which are four times as great, as the emissions in our cities from our cars is four to five times greater  than the emissions from our homes.

climateIt is for these reasons that Solar PV should be first and foremost thought of as a transportation fuel and secondarily as a utility offset for a home or business.

Both are awesome, both are needed, but there can be no doubt that the greatest environmental benefit and the greatest financial savings are when solar PV is used to replace gasoline.

As goes California, so goes the rest of the nation.  Bet on it.

We are demonstrating with this challenge that if you have an efficient home, efficient cars and solar PV, you can power your home and cars with sunshine zeroing out utility bills and gasoline bills.

As we progress forward, our experience and example becomes easier to do for others as solar becomes less expensive, efficiencies continue to improve, electric cars become better, less expensive and homes including the appliances, gizmos within, continue to become more efficient.  Energy storage via home and grid size batteries, on the near horizon, will also give a huge boost to solar and EV adoption rates.

We are just at a beginning.   But harvesting sunshine as a transportation fuel is spreading rapidly across America and it will not be stopped.

Sunshine is America’s new “gasoline.”

May your days be filled with sunshine, onto the month 11 “Driving to Net Zero” energy challenge results.

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Our best month ever generating 235 more kwh’s than we use. Roughly 35% or our solar PV is used to power the cars, 65% to power the home.

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We are now at 20,000 miles total of both BMW i3’s, We have used 4.74 megawatts of electricity. 4.2 miles per kwh.

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Imagine that your 2 car fuel cost and the cost of utilities for your home, could be below zero

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We are already below zero in both cost and usage this year and the peak season has not yet started. The world leading efficiency of our two BMW i3’s are the main reason.

Next month will be the conclusion of our 12 month “Driving to Net Zero” energy challenge.  What an amazing year for us.

Thanks as always for reading and your comments.


(Past “Driving To Net Zero” articles)

Category: BMW

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16 responses to "BMW i3 Driving to Net Zero Energy – Powered By Sunshine – Month 11 Update"
  1. Jeff Songster says:

    Congrats on the experience. Our family is coming along with you folks. We have 8kW of solar on the roof with a little room to grow the array in the future. We are driving 2 LEAFs and an old 2008 Prius. The LEAFs are in and out of the garage with 50 to 130 miles travelled daily… the Prius (our sons car) only goes about 50 miles a week. And until we replace it with a Tesla… our next EV purchase… the 2009 Ford FLEX gets driven a couple of times a month more as a bus than a highway cruiser (its strongest suit) because we are hauling 6 or 7 people at a time.
    So far so good! Enjoy your stories. Looking forward to summary of whole event.

    1. Big Solar says:

      thats a situation I’d like to see millions of families in.

    2. Speculawyer says:

      That’s the way to do it! It is quite liberating to pay nothing for electricity AND gasoline. And it really is that gasoline part that feels really good since it tends to be imported in large part, produces local toxic pollution, and greenhouse gases. We need to reduce that as low as possible.

    3. wraithnot says:

      Same here- our 3.5 kW system went live last week. It should be enough to offset our standard Model S and i3 usage (I have a relatively short 26-mile round trip daily commute and my wife works from home three or four days a week). But I’ll start monitoring how much energy it takes to charge the cars and compare with the output of the solar PV array just to make sure (I have a Belkin WeMo to monitor L1 charging and I use a chargepoint stations at work for L2 charging). We may add some more panels once we decide exactly where the new skylight over the kitchen is going.

      There is something very satisfying about making your own transportion fuel on your own roof 🙂

  2. Big Solar says:

    Nice picture! If that i3 wasn’t Revlon red I’d use it as my main wallpaper.

  3. sven says:


    You previously mentioned that you planned on replacing some of your natural gas appliances with electric ones when they reach end of life. I recently came across some very efficient heat-pump water heaters. They look promising, especially for San Diego’s climate.

    1. sven says:

      Actually, in a warmer climate like southern California a detached outside heat pump would be better than the indoor attached heat pump on this water heater.

      1. Speculawyer says:

        I don’t know what SDG&E offers but PG&E where I live has a $500 rebate if you buy an electric heat pump hot water heater:

  4. Peder says:

    Thank you Sven!

  5. vdiv says:

    Ever wonder why EVs are so popular on the West Coast, LA in particular?

    Making and refining gasoline on your rooftop, indeed!

  6. Kosh says:

    Happy May 1st everyone – beginning of the peak power season for us grid connected TOU’s… 😉

    1. Peder says:

      Peak harvest season is here!
      In SD (SDG&E) rates are:

      $0.48 Peak
      $0.22 Off peak
      $0.17 Super off peak.

      1. drpawansharma says:

        now that its clear that you produce more energy than you consume, are you going to consider the energy saving batteries that have been introduced by Tesla?

  7. Peder says:

    Energy storage is the holy grail and as Elon says the missing piece. He is absolutely spot on. We can get to 60%-70% solar and wind but storage will be required to go higher. Until then, it’s nat gas peaker plants.

    For now, utility scale and off grid locations are the best suited for batteries as well as areas that don’t have a dependable grid or suffer lots of interruptions.

    In our case we have a dependable grid and I believe in dense cities a grid is an efficient sharing system.

    So it will be a few generations of battery development down the road before I sever my tie to the grid.

    I love the tech and this is the start. Kudo’s to Tesla and Elon for being bold and moving us in the right direction.

    In away you can say I already have battery storage via our two BMW i3’s which we charge off peak and use during the day.


  8. jmollard says:

    Another point not made about PV is that it is effectively 100% efficient as compared to about 20% if you charged your EV from the grid. World electricity generation averages 33% ( and grid efficiency is only 60%. So your home PV takes five times the demand off the grid, and makes a real difference.

  9. Martin T says:


    Works for my Volt …. Nothing like driving on your OWN sunshine.

    No wonder governments and fuel companies are frantically pushing wasteful inefficient hydrogen fuel cells.
    How dare an owner drive on his on roof top sunshine filled up at home 🙂