The National Grid has told Al Gore and the Live Earth organisers that they can't request people go and switch off their lights for a symbolic moment during the concert because, erm, they don't know what would happen:
"The organisers had this idea and behaved responsibly by discussing it with us," he said.
"We are used to dealing with surges in demand, as it happens every day around certain TV programmes.
"But it's very difficult to forecast exactly what would happen in terms of demand. We would have had no idea how small or large it would be."
We're sure that's what they're worried about, and not the thought that people switching off their electrical items for five minutes would cost them and other electricity companies hundreds of thousands of pounds of lost revenue if multiplied by hundreds of thousands people.
We'd like to suggest a symbolic idea for Al, though: How about we all turn our televisions off when Madonna comes on stage?