Driving in savings-neutral territory so far

The first mass-market electric cars come on the U.S. market this year. The Chevy Volt, anticipated to be about $40,000, will be out in November, followed by the $32,780 Nissan Leaf in December. Both are billed as zero-emissions vehicles.

Solar power: The May 8 Realist Idealist column on recharging electric cars using solar power at home cited a company called 1 Block Off the Grid. The company prefers to go by One Block Off the Grid, or 1BOG. —

But the electricity has to come from somewhere, and in most places around the country that source is anything but green. In Los Angeles, 39% of the electricity generated by the Department of Water and Power is from coal, and 27% is from natural gas. Just 14% comes from renewable sources, such as hydroelectric power (6%) and wind (5%). Although the city has pledged to generate 20% of its electricity from renewables this year, fighting between City Hall and the Department of Water and Power threaten that ambitious goal, as well as a target set for 2020 that calls for renewables to reach 35%.

If you believe the climate scientists, the switch to renewable energy just isn’t happening fast enough to combat the greenhouse gases we’re spewing into the air. That’s why I did what many others have done: I installed photovoltaic panels at my house, partly so I can use solar power to charge an electric car.

Home energy consumption accounts for more than one-third of our country’s greenhouse gas emissions. Transportation accounts for another third. I wanted to wipe out my contributions to both.

That was my thinking when I decided to go solar in May 2009. I had spent a week testing my theory. I borrowed an electric BMW Mini E and charged it with the electricity I was generating from my rooftop solar panels. I wanted to better understand how much juice was needed to power a zero-emissions car and to see how the charging affected my electricity consumption.

Readers of this column may recall that in November 2008, I’d determined that solar panels weren’t feasible at my house because there was too much shade on my roof. But when I cut down a palm tree and trimmed back a ficus to grow fruit trees, I also ended up allowing enough sun to shine on my roof that I could go solar.

That tree trimming happened around the time I’d written up a blog post on a solar-buying group called 1 Block Off the Grid. The San Francisco-based firm gathers together possible solar buyers in a city, then negotiates a reduced group rate with the installer. When 1 Block Off the Grid was about to set up shop in L.A., I joined 16 other homeowners in the city and worked with installer REC Solar.

My roof faces southeast (rather than south) and has many planes, which complicate installation. Still, REC’s engineers came up with a plan for a 3.8-kilowatt system that, per my request, not only would supply all the electricity I was using at my house (about 4 kilowatt hours per day) but also power the electric car I planned to buy (requiring at least 3 kilowatt hours per day more, with regular charging).

That system came with a $23,635 price tag — an expense that would have been reduced to $10,311 after applying the 30% tax credit from the federal government and a $8,906 rebate from the L.A. DWP.

In theory.

The DWP uses a performance-based rebate system, and when it came time for the installation, the utility would rebate me only an amount comparable to the electricity I had been using, 4 kilowatt hours per day. That calculation reduced the rebate by $5,008. For a single mother and a journalist working in uncertain times, that reduction was a deal breaker. I couldn’t afford it.

DWP suggested that I buy an electric car before installing my system so I could get the higher rebate — advice that I couldn’t act upon because the only electric car available at that time was a $109,000 Tesla Roadster. REC Solar’s recommendation that I spend the next three months running every appliance and light bulb in my house 24/7 to jack up my electricity usage, and thereby my rebate, also was something I just couldn’t do, not in good conscience.

So I decided to proceed with a smaller 1.2-kilowatt system. The system was sized to match my current electricity use at the time and allowed me a DWP rebate to match. The system cost $11,564, for which I paid $7,666 up front after a DWP rebate. I received $2,300 back on my 2009 tax return because of federal incentives. That brought my total out-of-pocket cost to $5,366 — pretty much what I’d be spending on electricity for the next 20 years.

If only I had waited. It took six months for the installation to be completed and for DWP to sign off on its operation. During that time, the price of photovoltaics had dropped 21%, from the $7.08 per watt I paid when I signed my contract to the $5.56 per watt that 1 Block Off the Grid has managed to procure for its third and latest wave of L.A. installations.

Ouch. I certainly paid for being an early adopter. And I’m continuing to pay. When I got my latest DWP bill — the first since going solar — I was pleased to discover I was generating almost twice as much electricity as I was using, for which I was credited about $8 per month thanks to an arrangement allowing customers to be credited at retail rates for the power they’re making.

At current DWP rates, I’m making 16.7 cents per kilowatt hour during peak periods (10 a.m. to 8 p.m. Monday through Friday, June through September), when the sun is shining and rates are highest. And I’m paying 7.3 cents per kilowatt hour during off-peak, night and early morning hours, when I’m home and using electricity.

I was less pleased to discover that I still had to pay a $10-per-month “minimum charge” that DWP charges “for costs related to meter reading, billing and maintaining service for our solar customers,” I was told by a DWP spokeswoman. That fee pretty much wipes out any financial advantage I thought solar would provide.

On the up side, my experience has taught me how others can better navigate the system.

Anyone who wants to charge an electric car using rooftop solar at home should buy the car first. Doing so not only will ensure the maximum rebate from the utility but also make installation more cost effective. According to the folks at 1 Block Off the Grid, it’s better to install a large solar system from the get-go than to start small and add on later. Technical and logistical issues may include difficulty finding the same type of panels and a need to change the inverter that transforms solar energy into usable electricity.

I asked how much larger an installation would be needed to accommodate a car such as the Nissan Leaf, presuming a weekday commute of 20 miles. According to 1 Block Off the Grid, the system would need to be .79 kilowatt larger. Applying all applicable rebates, that would cost an additional $1,800. For a homeowner driving the same number of miles in a gasoline-powered vehicle, the system would pay for itself in three years.

Of course, this presumes that the electric car can be charged at home. Although the main reason I chose the BMW Mini E was its existence and availability to me, I also wanted it because the car can be charged with a standard 120-volt outlet, the kind you’d find in any U.S. home, or with a 240-volt charger, like the ones being installed around the nation at public charging stations (most likely to be operated for a fee). One of the points of my e-car experiment was to see how long it takes for one of these cars to charge and what sort of drain it put on a home electric system.

The short answer is a lot. The Mini E takes more than 24 hours to charge fully. It took me 26 hours to charge the battery to 70% of capacity, and it spiked my usage to almost double what my system was making. By comparison, when I took the Mini E to a BMW dealer to have it fast-charged with a 240-volt system, the battery was at 40% capacity in just 90 minutes.

Future electric car buyers, whether they use their existing outlets or upgrade to a 240-volt system at home, should charge their cars during off-peak hours to pay the lowest rate. In L.A., electric vehicle buyers will get a discount, reducing the per-kilowatt-hour rate by 2.5 cents.

I’m still planning to buy an electric car because it’s aligned with my values, because I’m using a lot less energy than my system is generating and because there are too many incentives not to do so. Although my experience taught me that I may have been better off waiting, it also taught me that people who want to make the same change shouldn’t wait long because the incentives for electric cars and solar panels won’t last forever.

My experiment showed me that my rooftop solar will practically make me energy neutral, even with a plug-in car. I paid a lot for solar, but the panels will likely pay me back in spades.

Past installments of Carpenter’s column on green home improvement and sustainable living are at Comments: