Top automakers finally have electric cars ready to purr into dealer showrooms. Now the question is whether the charging infrastructure and electricity supply are up to the task.

Industry watchers question if power grids can cope with the influx of electric vehicles, even though EVs are likely to remain, at least at first, a fraction of the new car market.

But as CO2 emissions rules tighten, carmakers need to take action. We need a radical solution, Renault and Nissan Chief Executive Carlos Ghosn said at the Paris Auto Show.

Renault, which with alliance partner Nissan is investing 4 billion euros ($5.5 billion) in electric cars, strengthened on Friday its EV partnership with French utility EDF.

At Renault's stand displaying the Fluence and Kangoo EVs and the electric Dezir concept car, the partners launched pilot projects on battery management and charging infrastructure.

EDF CEO Henri Proglio said he was confident of having the capacity to meet electricity needs of EVs.

He laughed off questions about whether EDF planned to increase prices to take advantage of extra demand at night -- when most drivers are expected to re-charge their cars.

There will be tariffs that, on the contrary, allow customers to benefit from off-peak hours. There are no plans to optimize the company's P&L by increasing prices, he said.

POWER PITFALLS

Carmakers are counting on EVs to help give them a leg up in markets that remain patchy, as September sales figures confirmed.

Ghosn said on Thursday his forecast that an EV would be one of every 10 new car sold by 2020 was now conservative.

Many manufacturers and analysts see much smaller demand.

PSA Peugeot Citroen forecasts EVs and hybrids -- which yoke electric motors to traditional engines -- will account altogether for 15 percent of the new car market in 2020.

Dominique Maillard, head of French electricity grid RTE, told Reuters before the show that if large numbers of drivers chose not to charge up overnight there could be problems.

This new (EV) demand will help fill up and balance the network during off-peak periods, he said.

On the other hand, if all drivers use quick charging in the daytime -- carmakers' most attractive sales argument to ease range anxiety -- the network will not hold up and it will definitely be necessary to reinforce it to get through peak points.

Thierry Koskas, head of Renault's EV project, said that a hypothetical two million electric cars on the road in France in 2020 -- quite an ambitious figure -- would represent 0.5 percent of electricity consumption in France.

What needs to be avoided is cars being charged during peak demand hours, for example 6 p.m. on a winter evening. That can be worked on, it's not very complicated, he said.

Victor Muller, CEO of Saab owner Spyker which is making 70 e-power EVs for a test program, told Reuters: The grid in the United States in many areas is so completely outdated that you could see serious problems arising.

Electric car drivers -- initially expected to be city dwellers, with companies accounting for a large part of sales -- will have a truly zero-emission vehicle only if it runs on electricity generated from renewable sources.

It's not only electric vehicles, we have to decarbonize the power sector, said Nobuo Tanaka, executive director of the International Energy Agency, which sees 20 million electric, hybrid and plug-in hybrid cars on the roads in 2020.

RANGE ANXIETY

Getting enough charging points in place so drivers can be free from range anxiety will be key, Muller said.

It's one thing to know you can do 50 km (30 miles) and you'll be without power. It's another if you don't know where to get power when you get there, he said.

Saab CEO Jan Ake Jonsson said manufacturers would also have to make sure prices for zero-emission cars were competitive.

The price tag at the moment is high. I would say it has to come to (that of) a normal combustion engine. If it doesn't, customers are not going to pay for it unless there are tax schemes and tax benefits.

Renault and Nissan offer electric vehicles only in markets that get government support, at least initially. Nissan started taking orders for its Leaf EV -- which costs around 30,000 euros including state incentives -- on Thursday in France. It stopped taking U.S. orders after it sold out the first year's output.

U.S.-based Fisker Automotive showed a production version of its plug-in hybrid Karma luxury sport coupes that will be priced at close to $100,000. It is in the planning stages for a second vehicle that will be far less expensive.

Tesla Motors Chief Executive Elon Musk -- whose company makes a $109,000 electric Roadster and plans a $57,400 sedan -- said state incentives were not decisive.

Even if there were zero government support I think Tesla would still be viable but our pace of progress would be much slower, he told Reuters.

But Fiat Chief Executive Sergio Marchionne said: I'm unconvinced today that we have the economic model to drive the cost structure down to the point that becomes economically viable for us as carmakers to become mass producers of EVs.

Fiat is investing in EVs to keep up with the technology, but I am a much firmer believer in hybrid technology in the medium to long term as being the ultimate solution to the reduction of consumption and CO2 emissions, Marchionne said.

Ghosn countered that a 20-30 percent reduction (in emissions that a hybrid can give) is not going to make it.

(Additional reporting by David Bailey and Danilo Masoni; Editing by Michael Shields)