Electric cars create dreams of lower oil imports, blue skies and reduced operating costs for owners. The news this week that the Chevy Volt, the electric car from General Motors, will get 230 miles to the gallon in city driving only reinforced those dreams.

But what happens to the nation’s grid if millions of people seek to recharge their hybrid vehicles each day after work? Or worse, what happens if many owners, cognizant of the limited charge in the battery, ignore daily peak demand and give their cars a quick jolt while at work, when stopping at the supermarket or a friend’s house?

The short answer: new demand created by gas-electric vehicles can be managed if – and the “ifs” quickly pile up.

The Electric Power Research Institute, an independent, nonprofit organization based in Palo Alto, California, says the US now has enough capacity to charge 1 million electric vehicles at night.

But major automakers, including General Motors, Ford (F), Toyota (TM), Honda (HMC) and Nissan (NSANY) are developing hybrids. The Oak Ridge National Laboratory expects annual US sales of plug-in electric hybrid vehicles to reach 1.5 million by 2016 with 50 million on the road by 2030. Then what?

For starters, load management will be the key to future success of hybrid vehicles. The basic assumption: it will take about 8 hours to recharge a hybrid car’s battery with 110-volt current commonly used in homes.

Night charging assumes drivers will respond to variable rates and recharge their hybrids when it’s cheaper.

But what if owners don’t want to tether their vehicles to an outlet at specified times each day to manage the load? Even with incentive pricing, people need to travel at all hours as evidenced by the heavy night traffic on major highways. Governmental mandates establishing recharging hours could hammer sales of electric vehicles because significant numbers of people want their car when they want it.

Adding new generating capacity will be difficult in view of environmentalists’ routine opposition to coal or nuclear plants and hydroelectric dams. If new capacity is approved, the Not-In-My-Backyard mentality kicks in – many favor new power plants as long as they’re built somewhere else.

Battery power is the yet-to-be solved problem for hybrid vehicles and may limit their future use. The new lithium-ion batteries store enough juice to power a car for about 40 miles, sufficient for most daily commutes but little else.

The Chevy Volt is expected to cost about $40,000 and even with an anticipated tax credit of about $7,500 the car will cost more than a comparable vehicle running on stinky gasoline. Daniel Indiviglio at The Atlantic crunched the numbers and determined that, assuming gasoline hovers around $3 per gallon, you’d have to drive 158,000 miles on the Volt to break even.

The Toyota Prius costs about $22,000. Maybe the higher cost of hybrids will undercut estimates of future sales, disappointing “clean car” advocates but easing the strain on the grid.

The charging stations needed for mass adoption of electric vehicles don’t yet exist. Other than someone else, who pays?

Utilities may face added costs, too. Hybrids appear to be popular among highly educated, upscale people. It’s not difficult to imagine increased demand by Zip Code if Yuppieville goes hybrid. Will hybrid owners be asked to pay for an upgraded distribution system by neighborhood or will the costs be spread to all customers in the entire service region? There are sure to be yelps either way.

Improved storage batteries will help ease future capacity concerns, but a report prepared for New York State’s utilities warns, “If the charging pattern of plug-in electric hybrid vehicles is not managed effectively, loads of this size could require significant additional generation capacity.”

That’s a polite way of saying there is no free lunch, a truism some have ignored in their enthusiasm for environmentally friendly cars.