Plug-in electric cars are now at the golly-gee-wow stage for most consumers, but utility companies are already thinking about how they’ll handle increased demand.

So far, the answer is differential pricing to encourage off-peak recharging of electric vehicles and a gradual increase in generating capacity.

The switch to rechargeable electric cars from gasoline-powered vehicles is expected to be gradual, giving utilities ample time to work out any supply problems.

But the rising cost of gasoline may create a rush to new electric cars despite the higher initial cost. If so -- and if production can keep up with stampeding demand -- there could be problems ahead.

General Motors (GM) and Toyota (TM) plan to offer rechargeable vehicles as soon as 2010. But the lithium-ion battery technology hasn’t been completely worked out, so you may not want to be the first on your block to buy one.

Some utilities in California are installing meters to track electric use by time of day. The idea: Charge a higher rate during peak demand to encourage shifts in discretionary usage (like charging your electric car's batteries) during off-peak hours.

PG&E (PCG) charges $0.30 per kilowatt hour to charge the batteries of an electric vehicle during peak hours but only $0.05 per kilowatt hour from midnight to 7 a.m. The smart consumer will rig up a time switch - and you can bet that everyone and his uncle will sell timers in the future if rechargeable electric cars become popular.

Sales of rechargeable electric vehicles could climb into the millions by 2020 if the price of gasoline continues to climb. For now, the gasoline-electric hybrids by Honda (HMC), Ford (F), Toyota and others offer a good way to improve mileage.

Will the increased load created by huge numbers of rechargeable electric vehicles ease objections to new nuclear and coal-fired generating plants or new hydro-electric projects? That would seem a reasonable trade-off for cleaning up smoggy skies in major cities - but don’t bet on it.