$re = '/1-0:1\.8\.1\x28([0-9]+\.[0-9]+)kWh\)/';
$str = '1-0:1.8.1(09865.000kWh)
1-0:1.8.2(11011.000kWh)';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php