THERE has been considerable progress with the introduction of electric cars, and the latest news is that countries like Norway and the Netherlands propose that all new cars must be electric from 2025, and India has suggested the same from five years later.

It's worth repeating the positives. A battery delivers 80 per cent of its electrical energy into turning the wheels whereas only 25 per cent of the chemical energy from petrol does the same. The result is that it's cheaper to run an electric car, as the seven kilowatts to cover 40 miles cost only 80p whereas the gallon of petrol needed would be over £5.

Additionally without a gear box, complicated transmission and cooling systems electric cars will be lighter, and cheaper to maintain and insure. Another bonus is that there's no exhaust pipe pollution, so city air would be cleaner, and healthier.

They will normally be charged at night when electricity is cheaper, and while it would be best if the electricity was produced by renewable means, it still means two thirds less CO2 per mile even if the power is from coal fired generation as the electric car is more efficient.

And yet an additional bonus could be that cars on charge at night could have the battery power reversed back into the grid to meet an exceptional peak demand, perhaps in winter, and so reduce the need for more power stations.

However there are still some serious challenges that need to be overcome and it's the batteries that present most of them. At the moment they are expensive, though reducing year by year as the market grows, and the distance they will cover on one charge is increasing.

While most small and affordable electric cars have a range below 100 miles there are a number now that can reach 150 or even 200 miles on one charge. The newest American Tesla vehicle will be ready next year and has a range of 215 miles, while the Chevrolet Bolt model can cover 200 miles.

It's clear that the next few years will see a massive expansion, with over one million electric vehicles already on the world's roads, and battery range apart, the next problem to overcome is the provision of enough charging points, at home, at work and in car parks.

The domestic arrangements will work well if the house has a separate garage or space for the car to be parked off road, but the real challenge will be in those areas where that's not possible. Many of our major cities have both tower blocks and terrace housing, and it will need a radical solution to change thousands of street-parked cars.