Michael Lewis, UK CEO of E.On had a bit of a Eureka moment, which he shared with the Future of Utilities conference this week, in London. He was arguing with a gas turbine executive about whether a carbon free future was even possible. Days later is was nagging him, so he sat down to write his presentation for the conference, and did the following calculations on the back of a cigarette packet or the modern equivalent. “I know you analyst types, don’t challenge the detail and tell me I’d got it wrong, look at the ideas behind these numbers,” Then he wrote 1,386 TWh (terawatt hours) in the first column as the total energy output of the UK, much of…