A forecast from Pike Research says that sales of hybrid and electric medium- and heavy-duty trucks will nearly double in 2012, but one industry expert thinks some of the numbers might be overly optimistic.

Pike believes the global market for hybrid electric vehicles (HEV), plug-in hybrid electrics vehicles (PHEV) and battery electric vehicles (BEV) will grow at 92% in 2012, with total sales surpassing 19,000.

In the U.S. this year, it predicts that 3,250 medium- and heavy-duty HEV trucks be sold, 790 BEV trucks will be sold and about 500 PHEV trucks will be sold.

In a slowly improving economy, driving factors of increased hybrid sales will likely be fleet owners' desire to advertise a more environmentally-friendly fleet than their competitors'. Also pushing sales is the bottom-line cost impact from government emission regulations, says Pike.

"The performance of specific economic sectors will play a big role in the growth of electric drivetrains for trucks," says Dave Hurst, senior analyst for Pike Research. "For example, as the retail industry rebounds, pick-up and delivery vehicle sales will rebound with it. This in turn will have a positive impact on the hybrid, plug-in, and battery electric truck markets, as well."

In its research report, "Hybrid Medium and Heavy Duty Trucks," Pike Research forecasted numbers through 2017. The firm expects the market to experience a compound annual growth rate of 42% between 2011 and 2017. In 2017, 100,746 hybrid and electric trucks are expected to sell globally.

In the U.S. in 2017, it's expected that 21,675 hybrid and electric MD and HD trucks will be sold. That's a growth rate of around 40% for hybrid and electric truck sales in the U.S. between now and 2017.

There are some obstacles that might stand in the way of growth in sales, however. One of those hurdles is the growing popularity of alternative fueled vehicles, particularly natural gas. Another is the high price tags on hybrid and electric vehicles. HEVs, PHEVs and BEVs all have higher upfront costs that are substantial enough to result in a higher total cost of ownership. Even with lower operating costs ($0.72/mile for diesel versus $0.60/mile for hybrid and $0.22/mile for BEV trucks, according to Pike), the higher purchase price for hybrids and electrics means the trucks aren't able to recover their costs in a lifetime without government incentives.

"The high price of diesel fuel is really getting fleets to consider alternatives," says John Boesel, CEO of CALSTART, an organization that supports a growing high-tech, clean transportation industry. "But I think growth rates that are projected here out to 2017 might be a bit aggressive. If they prove true, it'll be good for national security and the environment, but I think a lot will depend on the investment made by the manufacturers in improving the vehicles and driving down the cost of technology."

Boesel said a good example of this is the Toyota Prius. "We need to see a level of commitment by the [truck] manufacturers similar to the commitment made by Toyota with the Prius, where every two years, a better and lower-cost product came out," says Boesel.

"If that happens, we could see these predictions come true."