OIL companies say they are not threatened that big manufacturers plan to introduce electric cars over the next decade.Shell Australia said that with about 1 billion cars expected on the world’s roads by 2050 – twice the current number – and with the development of cleaner fuel by companies, its share of the car market was safe.A Shell spokesman, Paul Zennaro, said increased choice meant a win for the consumer. ”In the future there will be conventional fuels, biofuels will play a huge role and electricity as well. Our customers will decide the types of fuel they want to buy,” he said.But he added: ”Significant investment is required to move to any new form of energy. It takes decades of effort and collaboration between consumers, companies and government to make things happen.”BP Australia said it would watch the development of the electric car with interest but, because of the current restrictions on battery life, any real competition would be some way off.”It takes 15 years to turn over the current fleet of motor vehicles and the advantage for internal combustion engines is that the infrastructure is already here,” spokesman Jamie Jardine said.