Electricity for the BMW i3's produced just 15 feet above the cars.

Electricity for the BMW i3's produced just 15 feet above the cars.

We’re nine months along on our 12 month “Driving To Net Zero” challenge. To recap:

“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 BMW i3's driven 20,000 miles, with zero utility cost, and zero gasoline cost for 12 months.”

Yes we can! We popped the first bottle of champagne last month as we documented a whole year with no cost of energy and no cost of gasoline to power a home and to drive two EV's a collective 20,000 (actual 24,350) miles a year.

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

The year end True-Up bill, $-36.68 with an unused credit of $-434.57

The year end True-Up bill, $-36.68 with an unused credit of $-434.57

February of this year we used 333 kWh less than last February<br />(in the above chart.) This is due to the much more efficient BMW i3's that we<br />did not have for the first four months of last year.

February of this year we used 333 kWh less than last February
(in the above chart.) This is due to the much more efficient BMW i3's that we
did not have for the first four months of last year.

The second part of the challenge is far harder and speaking frankly, a little crazy to try.   We’re already below zero cost thanks to TOU pricing, any effort to go below zero cost is extremely expensive with zero financial return.

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

The three best months for solar PV are ahead of us & our<br />French exchange student is no longer here.

The three best months for solar PV are ahead of us & our
French exchange student is no longer here.

Can we make more energy than we use?   We’re going to be close.   We have a 1080 kWh gap to close in the next three months, a time when the sun shines the brightest and our energy use is the lowest. We project next month to be slightly below zero and then the following two months, we should generate 200-300 more kWhs per month than we use.

This puts us a little short but there are a few things working in our favor. Our French exchange student is no longer with us (that will save us a lot of kWh’s,) the BMW i3’s are far more efficient than the electric cars they replaced, and we have a few weeks vacation planned where we will be away from our cars and our home thus less energy use.  It will be very close, within a few 100 kWh's so stay tuned!

A Focus On Our BMW i3's Charging Station. 

ChargePoint CT 4000 dual head charger can charge both cars at the same time

ChargePoint CT 4000 dual head charger can charge both cars at the same time

When you drive a gas car, you have a mandatory relationship with a gas pump. On the face of the pump, you see the exact cost of the fill-up immediately. (that's usually not an occasion for happiness)

When you drive an electric car you have a relationship with your home, where you plug in every night.  If you chose too, you can have solar panels as part of the home and drive from the energy that you make.

In the above electric scenario, it's hard to calculate the cost of the energy used by the car as there is no readout "at the pump" and the electricity bill is shared with the house and only comes once a month.  Residential charging stations are "dumb" and a driver is left to figure out complicated calculations on their own such as usage and what part of the bill belongs to the car how much is lost in the charging process, and what part of the bill belongs to the house?   Let's not even talk about tired rates and is the car or the house responsible for what tier as rates rise? It just gets crazier!

There's a lot to be said about the simplicity of the gas pump with the price right in front of my eyes. To be blunt, we need to move to this in the electric car world and I'm amazed that we have not yet done so.

Thanks to ChargePoint, we are doing exactly that each and every time we charge. ChargePoint has provided us with a demonstration commercial CT4000 charging station with power-share for the duration of our Driving to Net Zero Challenge. It's a beautiful charging station with great cord management.

With this charging station we can charge both cars on separate ports at the same time and track each car separately by ports or combined by the station.   This is how we figure out exactly what each car uses in a month displayed next to the milage of the car for that month.  When you can track it, you can measure it, when you can measure it, you can adjust it.

This commercial charging station is expensive for residential use and way overbuilt in terms of what it can do, but there is good news on the horizon for a smart home charging station solution.

ChargePoint is soon releasing a residential charger called "ChargePoint Home" that is the smartest smallest and most advanced home electric vehicle charging station.  It's wifi connected and combined with their application and web software, EV drivers will be able to instantly tell, how much electricity they are pulling from the wall, how much electricity they have used,  and then assign a price per kWh to determine the cost of that charge up. It will also let you know how many miles you are putting back into the car and remind you if you have not plugged in for the night.

Coming soon, ChargePoint Home, a smart wifi connected charging station.

Coming soon, ChargePoint Home, a smart wifi connected charging station.

Below are some screen grabs of the information we pull off our ChargePoint CT4000 charging station.  Thank you again ChargePoint for the use of this charging station for our energy challenge.  Whether it's a bank account, a credit card, a utility bill or a car charging station, accurate and immediate data is important!

We can see our exact usage for the month for both cars. This is then<br />used in the Norby Home & Two BMW i3's energy graph. In this month,<br />Julie's car used 236 kWh and my car used 199 kWh.

We can see our exact usage for the month for both cars. This is then
used in the Norby Home & Two BMW i3's energy graph. In this month,
Julie's car used 236 kWh and my car used 199 kWh.

Our energy use during the whole energy challenge to date.

Our energy use during the whole energy challenge to date.

Our number of charging sessions per week during the challenge

Our number of charging sessions per week during the challenge

Our greenhouse gas reductions as calculated by ChargePoint

Our greenhouse gas reductions as calculated by ChargePoint

As always, thanks for reading and for your comments. Sunshine is a transportation fuel.

Cheers Peder

(Past "Driving To Net Zero" articles)