I'm concerned about the phasing out of cash too as a separate issue, I just don't think the cashless options should have to be subject to artificial limitations like requiring electricity or a network connection to be able to be used. I guess online transactions with chip and pin are much more secure and should be the default, but retailers could keep a log of outages that they are required to submit along with the imprinted slips. They could be corroborated with the logs of the utility companies as well as other businesses in the area, and if something doesn't make sense it could trigger an audit.