NEW YORK ( TheStreet) -- Sales of plug-in electric and hybrid cars in the U.S. basically tripled in 2012, from little over 17,000 cars to little over 50,000 cars. I am counting both pure electric cars ( Tesla ( TSLA), Nissan LEAF, etc.) and plug-in hybrids ( Chevrolet Volt, Ford ( F) C-Max Energi, etc.) here, as I believe this is the relevant measurement in the market at the moment.The 2012 best-seller in the U.S. market was the Chevrolet Volt, which sold little over 23,000 cars (plus some 7,000 units abroad, for those who are counting). The Toyota ( TM) Prius plug-in came in second at 13,000 cars, and the Nissan LEAF third at 10,000. Those three cars at 46,000 total were close to 90% of the plug-in electric market. At 2,374 cars starting late in the year, the Ford C-Max Energi was the bulk of the balance, at least if we don't count the Tesla Model S, which hasn't reported numbers yet, but where the final number was likely just above 3,000. What can we expect for 2013? Let's take these cars one by one, and then tally up an estimate. First, the Chevrolet Volt. The 2012 sales leader -- by a wide margin -- has a huge swing factor ahead for 2013. There appears to be no model change in store for the year, so a major threat to 2013 sales would arrive if details of a 2014 or 2015 Volt hit the market. Furthermore, GM ( GM) surely is counting on sales abroad to increase dramatically from the 7,000 level in 2012. GM will surely pull out all the stops to ensure that the 2013 U.S. sales level does not fall below the 2012 level. The customer satisfaction is there, with the Volt having the highest such of any car in the market for two years straight. On the upside, the sky is the limit. I think a conservative estimate is 30,000 units, but it could just as well turn out to be 40,000 or even 50,000, especially if gasoline prices go over $4 per gallon again. In the third quarter of 2013, deliveries of the Chevrolet Spark EV begin. At this point we should not assume significant sales, perhaps 3,000 for all of 2013.