asked the Secretary of State for Energy what is estimated to be the energy involved in producing one gallon of petrol manufactured from the liquefaction of coal.

The energy content of petrol is about 1·5 therms per gallon. On the basis of an overall process thermal efficiency of 60 per cent., the production of one gallon of petrol would require a total of about 2·5 therms, equivalent to the energy in 20 to 25 lbs. of coal.