I accept that if it can in any way be taken to be economically viable. I was at one time very keen on the idea but the more I have studied the practical figures of the unit cost of electricity generated the more I see that the thing is put out of court at the moment as impracticable. That does not mean to say that we should not look at these things in the future as engineering techniques develop.
My hon. Friend the Member for Bolton, East said that dirt in the ground today is gold in the hand tomorrow. That is a very interesting aspect of conservation. Nevertheless, we must reflect on the counter-argument put forward by the hon. Member for East Stirlingshire that there is a need to ensure that we are not complacent and are able to deal with problems involving the possibility of shortages in the immediate future. The need to be able to use indigenous supplies is of the greatest importance. This is why the Government have felt a need to ensure that we should maximise both exploration and exploitation of the North Sea oil hydrocarbons.
There were two main ingredients in the remarks of the hon. Member for Nuneaton. First, there were the measures designed to secure the greatest efficiency in the use of available energy sources-in other words, energy conservation measures. I have great sympathy with that view, and I am sure that nobody in any nation today should be foolish or wasteful in the use of energy. Secondly, there is the work intended to establish the scientific and economic implications of developing alternative sources of energy for transport purposes.
It has been calculated that in 1971 transport as a whole took about 14 per cent. of the United Kingdom's total consumption of primary fuel. Road transport accounted for over three-quarters of that 14 per cent. It will not surprise the House to learn that not only is that great majority of road transport mileage run by the private car but that this is by far the most inefficient method of travel in fuel efficiency terms. Measuring the average fuel consumed for each person carried, the average car figure is between 25 and 50 person-miles per gallon—depending on the character of the journey—compared with between 150 and 300 person-miles per gallon for an urban bus operating at peak times. It is right that the current work in this field should examine carefully the energy conservation implications of urban policies whose effect would be to transfer people from their cars to buses and trains.
Outside the urban and predominantly passenger fields there is the question of freight transport. In terms of ton-miles per gallon, a 700-ton freight train is nearly two and a half times better than the best lorry. However, rail is very much less favourable for the carriage of smaller loads. Few freight origins and destinations are at railway terminals, so that some road transport is inevitable. A road-rail-road journey between two points is nearly always longer than the corresponding road journey. The average length of freight haul by road is only 30 miles, and only 7 per cent. by weight is carried more than 100 miles.
Thus the great majority of present road freight transportation falls into the bracket where rail travel would not present a significant fuel saving. I thought that that was a matter, in view of the wild suggestions which have been made, which would be useful to put before the House.