Nissan Leaf beats Chevy Volt in May sales

Plug-in car sales continued at a steady pace in May, with early estimates of perhaps 6,500 to 7,000 sold overall.

As always, precise figures are impossible because Tesla Motors [NSDQ:TSLA] does not report monthly sales as every other carmaker does.

We'll refine our totals as more reports come in over the course of the day (and, for the Ford plug-in numbers, tomorrow).

Second-best month for Leaf

Fulfilling expectations of consistently higher deliveries, the May sales for the 2013 Nissan Leaf electric car came in at 2,138.

That's the Leaf's second-best sales month ever, trailing only March, when 2,236 were sold after supplies of U.S.-built plug-in electric cars finally started to reach Nissan dealers.

With five months gone, Leaf sales total 7,614, almost triple the 2,613 Leafs sold at this time last year. 

If Nissan can keep up the pace at the average of the last three months, it might deliver 22,500 or more Leafs for the year.

It's still worth noting, however, that the Leaf represented just 2 percent of Nissan's total of 106,558 sales in May.

Volt only holding steady

The Chevrolet Volt, the best-selling plug-in electric car last year, logged 1,607 deliveries--bringing its yearly total to 7,157.

That's just 100 cars more than last year's comparable total of 7,057, which doesn't exactly indicate sales growth for the Volt.

That total, moreover, puts it behind the Leaf in total sales for the year. The Volt and Leaf were neck and neck last month.

Total Volt sales last year were 23,461, more than twice the Leaf's total of 9,819.

GM's plug-in sales totals will see an addition at the end of the year, however, as the 2014 Cadillac ELR arrives at dealerships. The first pre-production ELRs have already been assembled.

Tesla: the big unknown

First-quarter sales of the Tesla Model S electric luxury sport sedan were reported by the company at roughly 4,900.

That made the Model S the best-selling plug-in car in the U.S. for that period. Unfortunately, we'll have to wait until sometime in July or August to know how many Model Ses it sold for the April-June period.

If U.S. monthly sales were to average 1,800 cars--which would take Tesla to its announced goal of 21,000 units for the year--the Model S would likely be the third best-selling plug-in car in the country.

However, some portion of those 21,000 Model S deliveries will come from Europe, where sales are starting this summer, and perhaps from Asia late in the year as well.

That means Tesla's monthly sales to U.S. buyers could drop considerably as it works through its list of buyers who've put down deposits, but the company could still meet its first full-year goal.

Whether the company will provide data on its sales by country remains unknown.

Plug-in hybrids strong

Ford's sales of its two Energi plug-in hybrid models surged in May, with the company announcing last week that it had sold more hybrids (regular and plug-in) through May than it did during all of 2012.

Sales numbers broken out for the Ford Fusion Energi and the Ford C-Max Energi will be released tomorrow.

Meanwhile, Toyota's sales of its Prius Plug-In Hybrid have been trailing off.

Compliance cars

With a price reduction to $259 monthly for a Honda Fit EV lease, and the Fiat 500e offering a $199 monthly lease (when it goes on sale in July), carmakers are showing that they intend to sell the legally required minimum number of "compliance cars" to meet the California zero-emission vehicle requirements.

The Toyota RAV4 EV, with its 103-mile EPA-rated range, remains a compliance car but one of a slightly different stripe.

And the Ford Focus Electric is now available in all 50 states, though it sells only at levels that put it into the compliance car bucket as well.

The final such battery-electric vehicle, the 2014 Chevrolet Spark EV, goes on sale this month in selected California and Oregon dealerships.

The rest

The only remaining plug-in car is the Mitsubishi i-MiEV electric minicar, which has not sold as well as the company had hoped.

Sales of the Coda Sedan, the Fisker Karma, and the Wheego Whip LiFe have never been reported, but won't make a difference to the overall numbers.