All of these things are not formal units of power and are only used to provide context to non-expert recipients of information, and as such are variable in size and are general averages (of whatever form) - and aimed to give people an understanding of scale only.

All of these things are not formal units of power and are only used to provide context to non-expert recipients of information, and as such are variable in size and are general averages (of whatever form) - and aimed to give people an understanding of scale only.

But do they give people an understanding or a false impression?  If say, a new wind farm is said to be able to power 5 million homes, some people might work out  that with 26 million homes in the UK that is roughly one fifth of household demand.  But what about industrial and other demands?  It does not say anything about those.  If we assume that one Home is equivalent to 400W, then 5MHomes is 2GW.  Total UK average demand is about 35GW.  Would it not be better to say that it will deliver 2GW which is 6% of current demand?  And then of course there is the additional demand once we decarbonise all of industry and transport.