DETROIT – A pair of emerging alternative fuels, electricity and natural gas, continue to swim against the current of nascent infrastructures struggling to expand and the “chicken-or-the-egg” scenario is keeping a lid on sales of those types of vehicles.

In the case of electric vehicles, experts see the ramp-up of public charging stations as sluggish. Of the 20,000 charging stations in the U.S., just over 8,000 are publicly available.

“Bottom line, all the talk about public charging isn’t happening,” says Britta Gross, director-Advanced Vehicle Commercialization Policy at General Motors. “It is home and workplace doing the heavy lifting.”

Gross tells a recent meeting of the National Assn. of Business Economists here that 84% of all charging events occur at home, according to a study of EV owners last year. Of the 16% not occurring at the home, a small fraction of charges are done at a public outlet.

That leaves some potential buyers, such as apartment dwellers, out in the cold, says Nick Nigro, senior manager-Transportation Initiatives at the Center for Climate and Energy Solutions.

“We think some people are getting forced out of the market,” Nigro says.

According to WardsAuto data, automakers delivered 98,089 battery-electric and plug-in hybrid-electric vehicles last year. Combined sales this year are on pace for an estimated 105,000 units.

Looking further down the road, the EV market expects to receive a jolt from the growing number of employers installing charging stations and picking up the tab for employees who want to plug in.

Gross says a recent survey of Chevrolet Volt owners revealed 39% are plugging in at work when the service is available. A similar poll of Nissan Leaf owners shows 32% tapping workplace charge ports.

“We’re really driving workplace charging,” Gross says of GM.

GM operates 400 charge ports at U.S. facilities and is one of more than 50 corporations pledged to support workplace charging as part of a Department of Energy initiative. The push aims to increase workplace charging tenfold in the next five years.

Gross says workplace charging serves as one solution for people without access to a home charger and has the potential to double the number of EV miles a driver travels. It also serves an important marketing role.

“It provides a visible showplace,” she says. “These vehicles are out there and real. All you do is plug in and go.”

Gross says efforts to broaden workplace charging would benefit from actions such as the Internal Revenue Service declaring EV charging at work as a non-taxable benefit for the employee and giving state government facilities the green light to provide the service to workers and visitors.

A public-charging infrastructure encounters other hurdles, Nigro adds, such as the relatively low cost of electricity.

“It is cheap,” he says. “How do you make it profitable? There are also a limited number of (electric) vehicles on the road. Both make (business plans) risky, increasing the cost of capital. We have to look at how we can unlock private funding.”

EV proponents hope the State of New York laid early groundwork on that front last year with its $1 billion Green Bank.

The Green Bank, also adopted by Connecticut and reportedly under consideration by California, puts public dollars to work with private-sector matching funds to spur a cleaner economy, with EV charging stations as a key element.

“States are very interested,” Nigro says.