The first customer takes ownership tomorrow of the all-electric Nissan LEAF. There’s no doubt that the imminent rollout of the Nissan LEAF, and the Chevy Volt, is a watershed event. At the same time, green car fans should have realistic expectations about how many of these EVs will hit U.S. roads in 2011. Combined sales of the LEAF and Volt—plus a few purchases and leases of the Fisker Karma, Ford Focus Electric, Coda sedan, Mitsubishi MiEV i, Think City, and Smart ED—might optimistically add up to 50,000 units (aided by very generous government incentives). But what lies ahead for this brave new automotive market, and how do we measure success?

The Half-Million Mark
Look no further than the Toyota Prius as the benchmark—especially when viewed from a global perspective. Ten years after hitting the U.S. market, and with zero government incentives for hybrids in place, Toyota sold 125,000 Priuses so far this year. Meanwhile in Japan—where fuel prices are higher and government incentives were in place until September—Toyota sold 297,500 Priuses in the first 11 months of the year. (Keep in mind that the total 2010 auto market in Japan is about 5 million—compared to about 11.5 million sales expected in the U.S. by the end of this year.)

The Prius was, in fact, the No. 1 selling car in Japan in November, marking the 18th successive month on top of the sales chart. The year-to-date Prius sales in Japan, just below 300,000, means the Toyota Prius will break all-time Japanese records for annual sales of an individual model.

Toyota’s domestic market in Japan represents about 60 percent of global Prius sales—and worldwide 2010 sales reached 400,000 Priuses through October (according to Wall Street Journal). If you consider that Toyota plans to expand the Prius to an entire line of vehicles—ranging in size from compact to crossover SUV, and will introduce a plug-in hybrid version with an all-electric range of about 14 miles—then annual sales will likely pass the half-million mark by next year.

The landmark hybrid is still setting the pace for consumer acceptance—and therefore global environmental impact. Yet, the race between the leading automakers and the competing alternative efficient technologies, from hybrid to pure electric, only gets more interesting from here.

Toyota Prius