Tuesday, December 28, 2010

2010 Review & 2011 Look Ahead

Since 2007 I have been driving an electric vehicle, powered by solar panels on the roof of my house. Each year I look at how much energy my driving used and how much the solar panels generated. I want my EV transportation to be better than net zero. So how did 2010 do? Let's take a look and then see what will change in 2011.

In 2010, the solar panels generated 3575 kWh. That is enough energy to drive my electric truck 5100 miles. I drove my EV only 4506 miles. This means the PV system generated 425 kWh more than my driving used; yet another year of free driving. 

Now that the first Chevy Volt and Nissan LEAF cars have been delivered, there is a lot of press about the coming wave of electric vehicles and how they could overwhelm the grid. Our "EV driving" home does just the opposite. We supply power to the grid during sunny days when the air conditioners are running and charge the EV overnight. We supply energy when it is most needed, and withdraw it when there is a surplus. This helps to stabilize the grid, not bring it crashing down.

Sure, not everyone that buys an EV will get solar, but once I was driving with electricity, the source of that electricity mattered more than it ever had when I flipped on a light switch. And unlike with gasoline, I had a choice to produce it myself. I hope this awakening experience is a common one in the next decade.

One final note about 2010 before we look to the future: Our PV system's 2010 production was below 2008 and 2009's output by ~6%. There are two reasons, first the system was offline for 31 days starting in late January when the house painters sprayed paint into the inverter exhaust vent and killed it. Our inverter manufacturer, SMA, was very cool about it and gave me a refurbished replacement unit for free even though this was clearly not their fault. The second reason for the reduced output was the predominantly cloudy weather in May and June of 2010 when compared to the previous two years. In short, 2010 had a cloudy, rainy spring.

Looking ahead to 2011, there is one big change planned. I have ordered a Nissan LEAF. In early December I was told the car should arrive in 4 to 7 months. This means I should get the car, my first brand new car ever, before my birthday in July. This car will change my EV energy consumption in two ways. First, my heavy non-aerodynamic induction-charged truck uses about 700 Wh per mile. The Nissan LEAF is rated to use 340 Wh per mile for 73 mile range by the EPA. With a little hypermiling, I think I'll be able to use only 250 Wh per mile for a 100 mile range. This means that I'll be using less than half the energy per mile in the LEAF than I am using today. On the flip-side, with the longer 100 mile range of the LEAF compared to the 35 mile range of my truck, I'll be able to drive the LEAF far more. It will be interesting to compare energy use of these two vehicles and how the longer range changes my driving habits.


  1. Congratulations on another solar-charged year, and best wishes for another great EV+PV year in 2011. I'm guessing it'll be the most exciting one yet, with the LEAF arriving soon (hopefully).

  2. Thats a good blog, solar energy are good for environment.

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