Gregory Meyer reports at CNBC that electricity generated by US wind farms fell 6 per cent in the first half of the year even as the nation expanded wind generation capacity by 9 per cent. The reason was some of the softest air currents in 40 years, cutting power sales from wind farms to utilities and the situation is likely to intensify into the first quarter of 2016 as the El NiƱo weather phenomenon holds back wind speeds around much of the US. "We never anticipated a drop-off in the wind resource as we have witnessed over the past six months," says David Crane.
Wind generated 4.4 per cent of US electricity last year, up from 0.4 per cent a decade earlier. But this year US wind plants' "capacity factor" has averaged just a third of their total generating capacity, down from 38 per cent in 2014. The EIA (U.S. Energy Information Administration) notes that slightly slower wind speeds can reduce output by a disproportionately large amount. "Capacity factors for wind turbines are largely determined by wind resources," according to their report "Because the output from a turbine varies nonlinearly with wind speed, small decreases in wind speeds can result in much larger changes in output and, in turn, capacity factors." In January of 2015, wind speeds remained 20 to 45 percent below normal on areas of the west coast, but it was especially bad in California, Oregon, and Washington, where those levels dropped to 50 percent below normal during the month of January.
Some also speculate the the increase in the number of wind farms may be having an effect. Since wind turbines extract kinetic energy from the air around them, and since less energy makes for weaker winds, turbines make it less windy. Technically speaking, the climate zone right behind a turbine (or behind all the turbines on a wind farm) experiences what's called a "wind speed vacuum," or a "momentum deficit." In other words, the air slows down and upwind turbines in a densely packed farm may weaken the breeze before it reaches the downwind ones. A study in 2013 also found that large wind farms could be expected to influence local and regional atmospheric circulations. "If wind farms were constructed on a truly massive scale," adds Daniel Engbar, "their cumulative momentum deficit could conceivably alter wind speeds on a global scale."
(Score: 4, Insightful) by Phoenix666 on Friday September 04 2015, @12:12PM
And where was this concern about distribution of heat when Robert Moses and his ilk were busy, busy, busy paving over a large chunk of the Earth's surface and creating heat islands? If we now cover those suburban box stores with solar panels and cover over the acres and acres of parking lot with solar panels (on stilts) then we'd probably do something to reverse the worrisome changes in heat distribution that those earlier policies already caused.
Washington DC delenda est.
(Score: 2) by frojack on Friday September 04 2015, @06:53PM
And yet we build solar farms in the desert, and the city heat island persists!
I point out your own argument seems to suggest even you believe there is a significant environmental effect to SOLAR.
No, you are mistaken. I've always had this sig.
(Score: 0) by Anonymous Coward on Friday September 04 2015, @10:24PM
A parody of your argument is not an agreement with it.