From large-scale energy storage to smart grids that can match demand with supply, we've already seen many potential solutions to the much touted "variability problem" of matching inconstant demand with the unpredicatble supply of renewables. Renewable Energy World has a detailed and fascinating look at how energy grids might deal with variability. It explores some of the potential solutions, like rapid response gas turbines and large-scale hydro-power storage, but it is perhaps most interesting in how it captures the nature of the problem itself, and what can cause it. It turns out that grid operators have to be as versed in upcoming television schedules as they do in energy technologies:
The work of TSOs (transmission service operators) throughout Europe, and their equivalents elsewhere, is fascinating: each conducting its own orchestra of power generating options, then importing or exporting some extra volume, to match fluctuating demand. Grid operators have practically no control over electricity demand. Their job is to respond, yet without ever being 100 percent certain what demand will be. Of course, consumption patterns have been recorded and analysed, so the TSOs know broadly what to expect, and when. In Britain the National Grid keeps a careful eye on the TV schedules; the end of a popular program can account for a surge in demand of over 1,000 MW as the nation rushes to boil kettles for tea, while a pause in live coverage of this year's Royal Wedding led to a remarkable 2,400 MW of kettle boiling.