Friday, May 16, 2014

BMW i3's, Driving to Net Zero Energy

The idea is a simple one: Harvest sunshine from the roof of your home to provide 100% of the power needed for your home and the two cars in the garage. That is our goal in this "Driving to Net Zero Challenge.

The 12 month documented journey began May 15, 2014. Our first posting of data will be around July 1st containing tabulated data from May 15th to June 15th.

We will begin with May, the April information is used as an example only. 

We will need to drive the most efficient cars to achieve our goal of net zero. We were very happy for BMW  to learn that the BMW i3 is the most efficient production car in the world. The BMW i3 has a combined EPA rating of 124 MPGe.

Said another way, the BMW i3 is a car that drives on 1/5th the energy of a typical new gasoline car in the USA. So 4/5ths of the journey to net zero is efficiency savings, 1/5th will be energy generation via solar PV.

It is this unbeatable combination of efficiency, luxury and performance that truly defines “premium” in an automobile in our opinion and why we choose to buy two BMW  i3’s.

Even though the  i3 is much larger in passenger space, leg room and cargo space than it's prototype predecessor the BMW ActiveE, it weighs 1350lbs less than the ActiveE and is 25% more efficient.

We took delivery of our first i3 "Thor" on May 15th, our second i3 will arrive within the next few days.  Our experience the past 5 years and 100,000 miles driving  the BMW Mini-E and the BMW ActiveE, have demonstrated to us that the range of the i3 fits in very comfortably with our suburban lifestyle and location.  Our home is in Carlsbad, CA , 30 miles north of San Diego.  We realize that in a more rural environment, two i3’s may not be a practical answer.  

In the above pics is our BMW i3 and six solar panels integrated into the roof of this small stone faced area of our home. If purchased today, these six panels would be 260 watts each for a system size of 1.56 kwh.  The panels use 81 square feet of roof space and will generate 2,400 kwh per year.  This  amount of electricity will power the BMW i3 for 10,200 miles a year.  (2,400 multiplied by 4.25 miles per kwh)

Just ponder that for a moment, 6 panels, 81 square feet of space producing electricity for over 25 years, powering a car for 250,000 miles of zero emission driving.


So how are we doing leading up to the start date of “The Drive to Zero?”  Here’s a quick look at our March to April energy use for our home and two cars (ActiveE and Honda Fit EV.)  With the BMW i'3s we will save around 1000 kwh each year thanks to the world leading efficiency of the car. 


Thought of the Month:
The Energy Grid,

The energy grid serves us well. I have no desire to be "off the grid" or off any of the other grids in our lives such as our transportation grid, social grid, food grid, communications grid, or monetary grid, just to name a few.

These giant sharing systems (grids) are a far more efficient way to deliver services than if we’re all hoarding our money in our mattresses, had no place to buy food, had no shared transportation network, and had no utility grid.

Our goal is not to remove us from the energy grid, but rather to help reinvent the grid and make it a more equitable, more resilient and more accessible grid. A grid where a family or a business is not just a payer, but also can be a payee if they provide a net benefit to the grid,  a grid that encourages more localized behind the meter efficiency savings and renewable energy production.

The key component in this re-imagined grid is smart data.  When we can see how our home uses energy we can select more efficient appliances and adjust our energy use in a more favorable way.  When we can see how much energy our cars are using and when they are using it, we can modify our charging times to optimize the savings, or to assist the grid by not charging during high demand times.  The gathering and displaying of data in a connected house is a key component of getting to net zero.  When we can measure it, we can improve it.

The energy grid to date has only been open on the income cash flow side to the big boys (utilities and power-plants,) but now over 100,000 of users are participating as owners of micro power-plants both benefiting the grid and themselves.  

Going off the grid may be the right answer for some.  For us, understanding and sharing is a good thing :)

We  appreciate you following us on this 12 month journey to net zero energy use.  We enjoy the dialog of different opinions and ideas in the comments as we all try to improve mobility and transportation for ourselves and future generations.


Link to April post:

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