Starting in Spring 2012, six Nissan Leaf electric cars will begin service as regular cabs in New York City, bringing all-electric driving to the busy metered masses of Manhattan. It's part of a test program to see how all-electric vehicles fare as taxis with further electrification of the New York City taxi fleet to follow.

Along with the six Nissan Leaf electrics, the city is looking to fix a serious problem we ourselves found — by installing new charging stations in the city. According to the New York City Taxi and Limousine Commission, the chargers will go up at fleet garages and in the homes of the Leaf owner-drivers. Additional chargers stationed in airport holding lots are currently being discussed, which will be good as the NYC Taxi and Limousine Commission lists the Leaf's range as 62 to 138 miles on a single charge.

The six Leafs will be divided up among three fleet-operators, with each pair of Leafs sharing a single medallion. This means that there won't ever be more than three Leafs on the streets at any one time. They won't have any partitions and other than some cameras to watch you in the backseat, they will be set up just like a regular Leaf on the inside.

The NYC Taxi and Limousine Commission described the program with an address to the upcoming participants, to be chosen in January.

This program is a real test with unknown results. We have worked to plan for the "what ifs," but there most likely will be bumps in the road. We want this program to be successful and hope that it will help lead to broader electric-vehicle applications in the taxi industry, but we will need your patience and assistance to get there.

Time will tell if either no-bullshit New Yorkers or the city's budget-minded taxi fleets will accept the new electric vehicles, but from the looks of this pilot program, it seems clear that the city is setting up to turn its cabs electric for good.

## DISCUSSION

This is a slightly edited copy-n-paste of a comment I posted here in January:

How much excess capacity does the U.S. electric grid have? Adding one electric car, or even a million electric cars, to the over 100 million cars in the U.S. isn't going to put that much of a strain, but how would the grid handle it if, say, a quarter or a half of the current fleet were replaced with all-electric cars? I don't know but I've got a calculator.

According to the U.S. Department of Energy we burn about 140 billion gallons of gasoline, 1.4 x 10^11 gallons, in the U.S. per year. Another USDOE page informs us that the total electric power generated per year in the U.S. is four million thousand megawatt-hours, 4 x 10 ^ 6 x 10 ^ 3 x 10 ^ 6 watt-hours or 4 x 10 ^ 15 watt-hours.

This Wikipedia article includes a chart showing the U.S. Government's GREET model equivalences for various fuels, which indicates that a gallon of gasoline is equivalent to 116,090 BTU whereas a kilowatt-hour equals 3,412 BTUs or in other words a gallon of gasoline is equivalent to 34 kilowatt-hours or 3.4 x 10 ^ 4 watt-hours. Thus 1.4 x 10^11 gallons of gasoline is equivalent to 5 x 10 ^ 15 watt-hours. In other words, the amount of energy we use in terms of gasoline is about 120 percent of all the electricity currently generated in the U.S.!

Back at the USDOE we see this chart of Existing Capacity by Energy Source, which shows that we can produce a total of a little more than a million megawatts, or 1 x 10 ^ 12 watts. 365 days in a year (not counting leap years) and 24 hours in a day adds up to 8,760 hours per year, 8.8 x 10 ^ 3 hours, so the total capacity is about 9 x 10 ^ 15 watt-hours, of which we currently are using only 4 x 10 ^ 15 watt-hours.

But electric cars are more thermally-efficient than gasoline-powered cars.The EPA rates the Volt in all-electric mode at 93 MPGe (miles-per-gallon equivalent), the Nissan Leaf at 99 MPGe, and the Mitsubishi i-MiEV at 112 MPGe. This would be two-and-a-half or three times more efficient than a gasoline-powered car of the same size. Let's be conservative and say 2.5; thus electric-powered cars use about 40% of the energy of comparable gasoline-powered cars. Going back to the amount of gasoline used per year in terms of watt-hours, if it takes 5 x 10 ^ 15 watt-hours to run all our gasoline-powered cars, then it should take 40% of that, 2 x 10 ^ 15 watt-hours, to power a comparable fleet of electric cars. Add that to our current consumption of electricity, 4 x 10 ^ 15 watt-hours, and you get a new total of 6 x 10 ^ 15 watt-hours, which is still only two-thirds of the nation's existing power generation capacity.To tell you the truth, I am kind of surprised at that result; I would have guessed elsewise. So I would appreciate it if somebody goes over those numbers and lets me know if I made some dumb decimal-place error somewhere.