# Near the top of the code
my %energy;

# Later on ...
    foreach my $el1(sort{$a <=> $b} keys %Winenergy) {
        #  push(@energy.$x , $Winenergy{$el1});    #LINE C
        #  print OUT "$el1\t $Winenergy{$el1}\n";

        $energy{"energy$x"} ||= [ ];                    # Initialize array ref
        push @{$energy{"energy$x"}}, $Winenergy{$el1};  # Save to appropriate array
    }