use strict;
use warnings;
use Win32::OLE;
use Win32::OLE::Const 'Microsoft Excel';

my $xl = Win32::OLE->new('Excel.Application');
$xl->{EnableEvents} = 0;
$xl->{Visible} = 1;

my $wb = $xl->Workbooks->Add;
my $sht = $wb->Sheets(1);
$sht->Cells(3,3)->{Value}="Here";
my $penultimate_column = $sht->UsedRange->SpecialCells(xlCellTypeLastCell)->{Column} - 1;
print $penultimate_column;