As it gives the government data that would be otherwise unavailable without a physical search, electrical consumption data collected at fifteen-minute intervals retained for a space of years constitutes a search under the Fourth Amendment. Given the significant government interests in the program, the fact that excessive electricity use isn't a crime per se, and that, according to a guarantee sent to users by the utility, third parties, including law enforcement, need a warrant for access to customer data, the search is a reasonable one.
http://media.ca7.uscourts.gov/cgi-bin/rssExec.pl?Submit=Display&Path=Y2018/D08-16/C:16-3766:J:Kanne:aut:T:fnOp:N:2203659:S:0
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.