No, it's not a spelling mistake. It's the jokey name given to the chart below, which shows how as solar PV power cells are installed, midday demand will fall away making the evening (the "head" of the "duck") the new peak period. (see the article here)
This is scary stuff for conventional monopolistic electricity utilities. Old-fashioned power stations (coal or nuclear) have to run all the time to provide baseload power. But if demand is collapsing in the middle of the day, the time when because of aircon units, it used to peak, not only must the cost of the power stations be spread over lower sales thus raising costs per kWh, but also this previously most profitable period in the day is now the least profitable (because deregulated/traded power prices are at their lowest)
The principal solution to the technical problem is obvious: storage. Six hours of solar power needs to be stored (on site prolly) to be released in the evening. That solves the technical issue, but it doesn't solve the utilities' economic issue, which is that distributed power means utility sales will decline.
Yet there are innovative and inventive ways round this. The utilities themselves could install CSP solar towers, which store the energy from the sun's heat and light at its maxima to release when needed later. Naturally, since it is for a peak period supply, they would charge peak period rates. Or the utilities could sell solar plus batteries to households and business, with the condition that the batteries are connected to the grid in such a way that their stored power can be called on by the gird at peak periods. The economic gains could be shared between the grid owner and the consumer. The utilities could even make money from financing their customers' solar, wind and batteries. Instead of providing power 24/7, they would provide (at a fee) the right to power at peak periods and the peak power itself (at a premium). The article itself has several other suggestions.
But the economic problems for utilities surely aren't going to go away by themselves. And their problems will become inexorably worse as renewable power costs drop.
Disclaimer. After nearly 40 years managing money for some of the largest life offices and investment managers in the world, I think I have something to offer. But I can't by law give you advice, and I do make mistakes. Remember: the unexpected sometimes happens. Oddly enough, the expected does too, but all too often it takes longer than you thought it would, or on the other hand happens more quickly than you expected. The Goddess of Markets punishes (eventually) greed, folly, laziness and arrogance. No matter how many years you've served Her. Take care. Be humble. And don't blame me.
BTW, clicking on most charts will produce the original-sized, i.e., bigger version.