Electric boilers - effect on power demand of a block of flats

Hello there.


I would like to  know if anyone on the forum has done a study of or knows about an existing study of the impact on power demand of introducing electric boilers to block of flats. 


I have been tasked with estimating the impact of a gradual migration to electric boilers for central and water heating in a modern block of flats. Nearly all of the flats currently use gas fired combi boilers.


I then have to present this information to UK Power Networks so that they can asses whether or not an increase in capacity to the building supply might be needed in future.  Finally I need to put any recommendations to the owners' management board.


Clearly electric boilers will have some impact on power demand.


I can start with an estimate of current power demand (worst case) for a typical flat.  To that end, I'll be doing a survey of about 25% of the flats to come up with a figure.


I can then apply the IET Electrical Installation Design Guide diversity calculations for a typical flat and then the building as a whole using figure 3.4 (IET Electrical Design Guide Nov 2008 page 33).


I can then do a second power consumption exercise adding the demand of a typical electric boiler per flat and then the whole building.


However, it's not clear to me if this approach will be suitable for a massive migration to electric boilers.  I need to be sure of my ground if I approach UK Power Networks with a demand figure.


If we look at the usual peak use of heating demand (morning and evening) a building full of electric boilers, to me, could add a significant load to existing street fuses and possibly even cable capacity.


I would be grateful for any suggestions and experience people could bring.


Kind regards


donf