“Dear Wind,” began a series of Internet ads launched this past spring by Idaho Power, the Gem State’s largest public utility, designed to deride the value of wind-generated energy. “You’re not here when I need you.”
For researcher and Stanford University professor Mark Jacobson, who recently co-authored a report in Proceedings of the National Academy of Sciences that confirmed enough wind capacity worldwide to power the globe more than 60 times over, the utility’s snarky ads actually ring true ... to an extent.
“Wind is intermittent,” he conceded in an interview for NPR’s Science Friday program in September, a key reason his article advocates using wind for half the world’s energy needs, or about 5.75 terawatts (TW), in a 2030 clean-energy economy.
The balance, he says, should be made up primarily of solar, with a dash of geothermal, hydroelectric, and concentrated (stored) solar energy. “[Wind and solar] are very complementary,” said Jacobson. “When winds are calm, it’s a sunny day, and vice versa. You don’t need expensive wind [energy] storage if you combine them optimally.”
To prove it, Jacobson and his research team overlaid their multisource formula for clean energy generation against two years of power demand in a representative California market. “We were able to match the hour-to-hour power demands ... with 98% reliability,” he said.
So how many 100-meter-tall wind turbines would it take to generate 5.75 TW of energy for electrical power, transportation, and other projected energy needs in 2030? About 4 million, said Jacobson, up from “several thousand” currently in operation worldwide generating about 237.5 megawatts of energy, of which North America accounts for one-fifth.