The European Network of Transmission System Operators for Electricity, ENTSOE-E, hold hourly demand data for each EU country. Their terms and conditions do not allow redistribution. It may be worth our while putting in a single, co-ordinated request to cover access to and redistribution of the archive.
Elexon manages the data for the GB network, and this is available half-hourly. Registration is free. They've been very helpful with our network of UK universities in facilitating access to data, to date. Again, a co-ordinated approach will be best. There are also several different variations of total demand available from the GB National Grid, also all half-hourly
