BMW i3 Driving to Net Zero Energy – Powered By Sunshine – Month 5 Update

NOV 3 2014 BY PEDER NORBY 18

Driving To Net Zero Energy Challenge

Driving To Net Zero Energy Challenge

Month Five, Two BMW i3’s and a Home, $-718 Utility Credit, $0.00 Cost of Gasoline

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 for 12 months.

Our prior cars were a Volvo S60R and an Infinity G35. We spent $5000 a year on gasoline and $4000 a year on electricity.

Our prior cars were a Volvo S60R and an Infinity G35.
We spent $5000 a year on gasoline and $4000 a year on electricity.

We now drive the most efficient cars in the world powered by sunshine. The asterisk on the cost represents the cost of natural gas, which is offset by a larger credit for electricity. Unfortunately the credit is not transferrable with our utility SDG&E.

We now drive the most efficient cars in the world powered by sunshine.
The asterisk on the cost represents the cost of natural gas,
which is offset by a larger credit for electricity.
Unfortunately the credit is not transferrable with our utility SDG&E.

So how are we doing after five months?

  • We continue to amass a large bill credit now at $-718.
  • We have used a net of 11kWh of electricity more than we have produced.
  • We are driving 20% more than we anticipated, now at 10,700 miles.
  • We have an unplanned for, exchange student in our home for the year.
  • Solar PV is beginning to tail off for the winter.Screen Shot 2014-10-15 at 7.23.04 PM
    Less driving in October as we were both away on business for a week.

    Less driving in October as we were both away on business for a week.

    We have gone into positive energy use from SDG&E of 11 kWh

    We have gone into positive energy use from SDG&E of 11 kWh

Summer is now past and we continue on our quest, “Driving to Net Zero Energy Challenge.” After five months of living and driving we have amassed a large electricity credit of $-718 against a natural gas bill of $92 and we have used close to zero (11 kWh,) about $1.50 worth of net electricity.

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

It’s clear to us knowing our past few years of usage, that we will achieve our goal of harvesting sunshine from our roof, providing 100% of the energy needed to power our home and two cars with zero utility cost, and zero gasoline cost for a year.

We anticipate accomplishing this goal four months earlier than planned at our annual utility bill true up in January. That true up bill will have a big fat goose egg at the bottom with an unused credit of around $-450.

After nine months of driving two EV's (prior EV's were the BMW ActiveE and Honda Fit EV) and our home energy use, we have amassed a credit of $-614. We should finish the year with a  ~$450 credit for electricity against a ~$225 cost of Natural gas.

After nine months of driving two EV’s
(prior EV’s were the BMW ActiveE and Honda Fit EV) and our home energy use,
we have amassed a credit of $-614. We should finish the year with a
~$450 credit for electricity against a ~$225 cost of Natural gas.

The harder goal to reach will be actual net zero energy consumption. It should be pointed out that there is no financial benefit, only cost, once you have a zero energy bill and any effort to conserve beyond that goes as a gift to the utility.

We anticipate being within ~700 kwh of this goal at the end of 12 months so it’s going to be very close. If we have a warm and sunny winter/spring we might just make this goal as well.

The unanticipated factors working against us are:

1. We are currently driving at a 25,000 mile a year rate for our two BMW i3’s, we anticipated 20,000 miles. These 5,000 extra miles are the equivalent of 1,200 kWhs.

2. We have invited a Rotary Youth Exchange student from France into our home for the year. Lots of blow drying, curling iron and electronic gizmos 🙂

Our two BMW i3’s

Sungas and Sungas 2 are amazing cars and we are enjoying them very much. You can feel the lightness and the rigidity of the CFRP, which combined with the regenerative braking, provides for a driving experience unlike any car I have driven before. I really look forward to a future coupe or sports car from BMW using rear wheel electric drive, lightness, CFRP and strong regen.

The combination of being the most efficient production car in the world at 124 mpge (5X the average 25mpg car on the road,) being a blast to drive with 0-60 times in the 6.5 second range with slot car driving characteristics and surrounded by the best interior design/materials of any car I have ever seen, is a yet unmatched feat in the automobile world.

With the BMW i3, efficiency, performance, sustainability, high quality design and incredible materials such as CFRP are not in conflict, but rather work together leveraging the strengths of each, resulting in an evolutionary change in how I view the future of the private car. It’s only going to get better as we head into the future.

More on our experience living with and driving the BMW i3’s in an upcoming mid month post.

Thanks for reading and commenting. You can live & drive on sunshine.

(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

Update Month 4

*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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18 Comments on "BMW i3 Driving to Net Zero Energy – Powered By Sunshine – Month 5 Update"

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It is noteworthy to mention that the utility won’t pay for a negative consumption. In more i have a colleague that happen to have a day and night differentiated metering and, guess what, the extra production during the day time could not offset consumption at night time. So even if he had produced 500 kWh extra during the day it was not paid for and not retrieved from the night consumption as well which is close to robbery actually since the utility effectively received that power. My advice was to start the dishwasher during the day instead of at night as usual so that he would use more in the day the at the night and so likely shift the 500 kWh loss from day out of the night and so in effect indeed reduce his night bill.

What utility is this? Here (PG&E) it is based on a yearly calendar, and so we do get to turn the meter backwards and “save it up” for night time use.

On top of that, our summer (over generation at higher rates) helps to offset the winter at lower rates.

Time of Use metering, grid storage.

Sounds like your friend got a raw deal.

Seeing that orange logo makes me want a bacon cheeseburger from Whataburger. Southerners will know what I mean.

We just completed our first month living in AZ with a roof top solar array and an BMW i3 BEV. Our monthly expense is $85 for the solar array lease including $20 to connect to the electric service grid. For that $85 we drove 822 miles pollution free in the i3 and used 1100 kWh of energy for the home and to power the car. We are delighted!

Great stuff!! Love the license plates. Have you thought of getting rid of the natural gas? I had the local utility take my gas meter away in Jan. I use a Reem Marathon hot water heater with a timer and have a super efficient Mitsubishi ductless heat pump to heat and cool the house. All powered with solar PV of course. I can’t make natural gas but I can make electricity.

Good input on the details of how the utility rules are structured. It is very similar in AZ. We also have to wipe the slate clean at the end of the year. I’m on a flat rate plan because I put my solar system in 6 years ago and the utilities hadn’t yet toughened up the rules. My utility (APS) now has put in a rule that requires ALL solar users on TOU plans….but I’m grandfathered into the old flat rate plan so I don’t have to be on TOU. APS has also now instituted a charge for net metering. It is charged monthly on your bill. Basically it is a charge for using the utility as a storage battery as we all do when using a grid tied system. Mark H lives in NC and his utility is VERY solar user unfriendly. So, if you are going to put in solar, STUDY UP on YOUT UTILITIES RULES….. they vary considerably depending on which state and which utility within that state. Also if you are thinking about solar then spend some time on the decision about going with an AC grid tied inverter system. AC grid tied systems are much… Read more »

I was reading that a new solar inverter is coming on to the market that will keep your solar power on when the grid falls down. Such as the new solar inverter seals off your house from the grid when the grid falls so that during the day you have power to your house.

I believe Sunny Mountain now has a grid tied AC inverter system that allows you to draw power when the sun is out and the grid is down. So if you are going with grid tie system then check into the Sunny Mountain system.

@GeorgeS – I -must- be misunderstanding entirely here, as utilities are all over the place on the grid-tie subjest, but a simple, physical throw switch -should- eliminate your need for Two inverters.

The utilities only (and rightfully) want to ensure that you are Not powering the grid when workmen are trying to repair it.

Basic grid-tie inverters will shut down if they don’t detect the grid. So you can throw the isolation switch, but the inverter is still off. You would need to have an oscillator that tricks theinverter into thinking it still sees the grid. For that you need batteries to run it. This is called AC Coupling. There are commercially available modules for this purpose George. It sounds like you are trying to jury rig something.

http://www.wholesalesolar.com/AC-coupling.html

Yes. Thank goodness I discovered this before I committed. The solution is to install an inverted specifically designed for this purpose. A “grid-tie with battery backup” inverter. I know that Outback (an American company) makes a line of these, but they are not the only ones. I have an Outback Radian GS8048, and it is a very nice product. It takes all the inputs: PV, batteries, generator, AND the grid, and it is in control, it decides when to use what. It is specifically designed to keep your loads powered even when the grid is down, but without back feeding (islanding). It is very effective. Over the last year since that inverter was installed at my house, the grid has been disconnected from the house several times. When it happens, you can barely see the lights flicker as the inverter switches to battery and PV power. We tested at the meter to be sure, and there is no back feeding. The Radian has numerous modes of operation, including grid-tie, off grid, and mini-grid. The latter allows you to defeat the power companies when they succeed in legislating net metering out of existence. You just have to put in enough batteries,… Read more »