"Higher prices at peak times might make a difference to demand at the margin but would for the most part be a tax on commuters who have no effective choice over how or when they travel, " the MPs said.

BBC: Higher peak-time rail fares opposed

While still the No. 1 show by a sizable margin, Idol viewership has been shrinking since its peak in 2005, when it averaged 30 million weekly viewers.

FORBES: Simon Out At Idol

Which is what leads to our interesting problem: the margin for error, the gap between the entire system working at full output and potential peak demand is going to be only 4% of that peak demand.

FORBES: The Joy Of Green Energy: The Lights Go Out In 2015