If your power is out at your house, then there is a high probability that the power is also out at your neighborhood network connection server. If that’s the case, then SENSE will not be able to transmit any data. You want to be able to measure how much wattage you are consuming from your portable generator during an emergency and not rely on a remote server connection.
I have the same setup that you have and also wanted SENSE to detect my power usage. I have several blogs where I discussed my setup.