Electrical energy is transmitted every hour of every day, and generators located across the country can supply demand anywhere in the UK due to a reliable and effective Electricity Transmission network. 

When demand grows in parts of the country or a new generator is being built, further investment in the transmission network may be required to transmit the increased power levels. Key boundaries between regions in the UK are identified and studied to decide how much investment is required, where it is needed, and when this investment in the transmission system should be made.