Residential its harder but an industrial/commercial property could possibly have multiple power inlines, a diesel generator for emergency power, and perhaps solar panels on the roof and batteries. It may have agreement to use power within specific ranges during the day for different prices and supply power back to a power company or neighbouring businesses.

Under those conditions it's always possible to divert power to 'adjust' the perceived power usage.

My point was that block chain doesn't validate anything - a private key will prove that the data (good or bad) is from the specific user, block chain won't validate that its good.

If the only way to cheat is illegal and can be done on the Blockchain anyway then why use a Blockchain rather than a database?

When a meter company catches someone cheating do we want them to be able to rectify in their database or fork an entire blockchain?

If we're relying on "what is legal" for validating data why do we need a blockchain?

If something being illegal is enough to solve your problem, then why do you need blockchain?

oooh, it's illegal! but I thought the libertarian blockchain utopia wanted to get rid of any entities enforcing law because that's soooo socialist?