Net Zero? Really?
- Jan 09, 2012
There was recently an article in my local paper about new “net zero energy” houses being constructed in Orange County, Calif. The headline on the piece referenced the homes being “nearly ready for electric cars.” A conversation with the developer (Herb Gardner of City Ventures) ensued, in which some of the nuances of home charging for electric cars was explored. Now that I am a driver of an electric car (thanks, Nissan, I finally got my Leaf and I love it!), I was intrigued.
I’ve been following the emergence of the viable electric car for some time, looking forward to the day I would drive one. Now that I do drive one (well, share it with my wife actually), I’m pleased with the opportunities it brings me to be an evangelist for more sustainable behaviors. Everybody wants to know about the car, and what it means to own one.
Let’s be clear: they’re not for everybody. As with many “greener” behaviors, it takes conviction, discipline and planning to make it work. My wife and I took a thorough look at our driving habits before making the leap. I was motivated to get a vehicle that qualified for car pool lane access in California, since the stickers for my Prius expired at the end of June. The Leaf was the best option. (Though I’m able to take heavy rail into the city for work most days, there are times when driving is required, and the commute from my home to my office is punishing without the use of the HOV lanes.) Because it’s 38 miles one way, it was iffy whether the Leaf would make the round trip journey on a single charge. This caused me to sniff around to find available charging stations in a reasonable vicinity of my office. The default location was the downtown Nissan dealer, where I could charge up in a pinch. As it has turned out, I have also started a new job, and there are two charging stations in our parking structure, which were installed just last November! Now my “range anxiety” is abated on those days when it’s necessary to take my car to work—I just charge up at either end of the journey.
The rest of the time, my wife drives it. She very typically travels fewer than 60 miles a day, running errands and seeing clients, which is the perfect application for this car.
We installed a special 240-volt charging station in our garage, which took some cash. But guess what? The California Vehicle Rebate Program found us eligible for an incentive that completely covers the cost. In addition, my utility company has offered us a special rate for overnight charging, which is what we typically do. (The very clever Leaf has a timer for charging that makes it easy to capitalize on the lowest tier rates, which start at midnight.)
Occasionally we also “top off the tank” in the middle of the day. One would typically want to avoid this because of peak-hour electricity rates, but we are able to generally relax about it because the photovoltaic panels on our roof are cranking out power at that time, so we are generally juicing it ourselves without the utility’s help.
These two items—the charging station and the PV—were what was considered necessary to have a new home “electric car-ready.” Mr. Gardner made the beautiful and very compelling argument that when one buys a home so equipped, one will save a great deal of money on both gasoline and electricity. The cost of these items would just be incorporated into the price of the house.
But “net zero?” That’s a horse of just a slightly different color. To achieve NZE in this example house, more energy would need to be produced than consumed. This is not as difficult as it may seem. With PV, more energy is produced during the day (usually) than the house (and car, in this case) consume, power is fed back into the grid, and the electric meter spins backwards. Then, at night, when rates are lower, the home draws from the grid, but usually at a much lower volume. As long as the excess energy generated during the day that is fed back into the grid is more than what is consumed at night, the property is considered “net zero energy.” The trick is to anticipate the home’s demand and design a PV system that generates enough juice to just barely exceed it. (Even the greenest green might be reluctant to provide any more free power back to the utility than is absolutely necessary.)
I haven’t yet assessed how much juice the Leaf is drawing. I know that I still have space on my roof, and the sun is still shining, so maybe some day in the not-too-distant future, I too will achieve NZE at my house. But wouldn’t it be great to walk right into a house that was good to go in the first place? I believe Mr. Gardner is on to something.
(Daniel Gehman is an associate at Harley Ellis Devereaux in Los Angeles, where he leads the Corporate and Commercial studio. He can be reached at firstname.lastname@example.org.)