Power-supply engineers are required to control the impact of their activities on the consumer, the system and the environment. The integrated transmission system enhances the control of costs of generation and of energy to the consumer. Load is met by the provision of spare generation, but advantage should be taken of systems for load management in the future. European interconnection, with pooled resources, will be beneficial, and a d.c. interconnection with France is being considered using thyristor-valve technology. Effects of faults can be severe. Advances in circuit breakers and protection systems using microprocessors are enabling shorter fault-clearance times to be achieved. More automatic control is leading to a more reliable supply by rapid restoration of circuits, even in extreme weather conditions. Economy in the use of expensive circuit breakers can result in complexity of auxiliary connections, but the computer provides both design and commissioning capability. System control using computer technology is being extended and will be adapted to the provision of a 2-tier hierarchy in the future. Control of environmental impact is achieved by sympathetic siting of substations and route selection for lines. A new line design at 400 kV should reduce the wirescape and provide lighter and smaller towers.