This will make the webserver call as a background task, so control will be given back to the service immediately, rather than it waiting for the wget to complete.

callenergenie.sh

echo Calling energenie socket...
wget --quiet --background --output-document="callenergenie.log" "http://192.168.1.99/callenergenie.php?delay=10&switch=2&state=off"
echo Sleeping for 2 seconds
sleep 2
echo Done.
exit 0