One House – Two BMW i3s – Powered Solely By Sunshine
There’s something traditional, in an American sense, about a home and two cars in the garage. We are a nation that came of age the past 100 years concurrent with the era of the automobile. For better or worse our homes and cars are together entwined with the embodied energy of our built history. For better, we can power both our homes and our cars with harvested sunshine.
On May 15th 2014, we will begin a documented 12 month effort to power our home and our two cars, each driven an average of 12,000 miles, by sunshine harvested from the roof of our home.
We will attempt to make more kwhs than we use over the entire year. We will attempt to be a true zero emission transportation solution, net zero in use and below net zero in the total cost of energy. We will document all with our utility bills and car readouts and share our somewhat private information with you openly at the beginning of each month. We’ve done the math, we’ve lived this EV + PV life for 6 years, we’ve been below zero with our home and one car, we believe we can do it with two.
Just as the cell phone, the digital camera memory chip and the computer have transformed how we communicate the past 20 years, Innovation and advances in technology have led us to an arrival at an important new intersection with our energy and transportation future. An intersection where there is an emerging “symbiosis” of the building, the automobile, and the energy plant all working together as a self contained system owned by a single entity, rather than separate entities at separate locations such as a home, a gas station and a power-plant.
It is a time primed for great change in how we make and distribute energy and how we motor from place to place. A time when new entrepreneurs will take up the challenge and lead us into an exciting and imaginative energy and transportation future.
Our goal is to save money, to be more self reliant, to lesson our dependency on foreign oil and its related cost in dollars and lives, and to improve the air quality in our city. Our goal is also to be a demonstration of this rapidly emerging and symbiotic new energy and transportation future.
We live in Carlsbad California in a temperate climate. We were owner builders of our home in 2006. Our home was nominated and was awarded the 2008 California Center For Sustainability Energy “Excellence Award” for being a net zero energy home. This award is peer reviewed and goes to one homeowner per year in Southern California. The main home is 3,250 sq. ft. There is a 1,200 sq. ft. guest home occupied by one. Our home and guest home use approximately 5,000 kwhs a year of energy, less than half of the average home electricity use in the U.S.
Our solar PV system
In early 2007 we purchased a SunPower 7.5 kw system installed by Stellar Solar that generates approximately 11,500kwh a year. This 7.5 kw system was architecturally integrated into our home at the plan stage and was sized to power the home and one car. This system was completely paid off in utility savings and gasoline savings in April of 2012.
In April of 2014, we added an additional 1kw of panels for a total system size of 8.5kw generating 13,000kwh a year. Our system is grid connected, we charge our cars at night from the grid when it is less expensive and less taxing to the grid and we generate extra kwhs for the grid during peak hours, providing this energy to our neighbors during peak demand.
Julie and I will both be drivers of the fully electric BMW i3. We expect to take delivery around May 1st. The BMW i3 is one of the most efficient cars and just might be the most efficient car in the world. It is a dream to drive with leading edge technology, comfort and safety.
Julie and I have been field trial drivers of both the BMW Mini-E and BMW ActiveE for the past five years and both of these cars have fit perfectly into our lifestyles requiring no concessions on our part. I drive approximately 9,000 miles a year and will use approximately 2,000 kwh per year. Julie drives approximately 15,000 miles a year and will use 3,600 kwh per year.
Of special note, the BMW i3 at 2,650 lbs is 1,400 lbs or about 30% lighter than our current car the 4,050 lbs BMW ActiveE. This lightness will save us over 1000 kwhs of energy each year for the same miles travelled.
The total usage of the cars and the home equal ~10,600 kwhs per year. The remaining 2,400 kwh (about $860 at the top tier rate of 36 cents per kwh) will be used to offset our annual $250 natural gas bill.
An asterisk here as even though the energy is priced retail at 36cents per kwh and our excess generation is sold to our neighbors by SDG&E at that price, they only credit our account 3.8 cents per kwh for excess generation and you cannot carry over the credit to offset your natural gas bill.
A therm of natural gas contains the energy equal to 29.3 kwh of electricity. So our generation of extra kwh will offset the therms of natural gas that we use.
We’re attempting this and are willing to document and share, success or failure, as we believe that this “Sunshine Symbiosis” will soon become the standard with millions of “symbiotic homes, cars and solar power-plants” accomplishing this same result in just a short decade or so. Solar is getting cheaper with a smaller footprint, houses are getting more efficient, and electric cars are getting better, more efficient and less expensive. Put that all together and you have disruptive change and awesomeness 🙂
Lastly, we are saving about $7,500 annually in fuel cost and utility cost. Our power-plant installed in 2007 is completely paid off with the savings of the past 5 years. We are living and driving at 20% the total cost of traditional utilities and gasoline. We look forward to those savings for the rest of our lives.
We are on a great path America, let’s put the pedal to the CFRP (carbon fiber reinforced plastic) and motor towards a better future.
I’ll update this effort with a new post around the first of every month.
Cheers & Sunshine,
*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 95,000 EV miles powered from roof top solar.