THE question of the standardization of electricity supply tariffs is of interest to many. A recent paper read by J. F. M. Mellor to the Students' Section of the Institution of Electrical Engineers on the basis on which those tariffs are founded is both a timely and a useful one. There are many difficulties in the way of getting an equitable solution to some of these problems. Take the case, for example, of an ‘isolated consumer’, that is, one who is at a considerable distance from the supply mains. In this case it is quite customary to charge the consumer the whole or part of the interest and depreciation on the capital cost of the mains extensions to his premises. It is reasonable, therefore, to expect that in the event of other consumers being connected on to these extensions, some refund should be made to the original consumer, and this should be mentioned in his agreement. The difficulty arises as to the period of time after the laying of the mains before the liability of the supply authority ceases. Another difficulty is that the time of the peak load varies owing to the great increase in domestic water heaters and thermal storage apparatus which has recently occurred. In many places, when making a long-term agreement, no period of the day or night can now be regarded as ‘off peak’ and allowed for at a cheaper rate. A supply for a fixed number of hours per day at the lower rate can be arranged, but this is not so attractive to the consumer. Everyone agrees that standardization is desirable, but there are difficulties in the way until the many small undertakings in the country are amalgamated with the larger authorities. When this comes, a lowering of the tariffs will follow in the country districts, since the ‘diversity’ of the combined load will be increased and so less spare plant be required. A broader policy also can be adopted.