Midwest Energy News (St. Paul, Min., Sept. 18) – Solar power’s “duck-curve” problem – where solar production and demand peaks don’t align – is rearing its head where grid operators are at the cutting edge of clean energy, recent analysis shows. “The units that we have and the amount of capacity that have that ramping capability is limited,” says George Gross, a professor of electrical and computer engineering at Illinois. “I can’t tell a solar unit to ramp up … [but] I can do that with gas-powered units.”