Hexbyte – Tech News – Ars Technica |
Dotting i’s and eating your peas —
So if US switched entirely to wind turbines, what is the trade-off?
The solution to climate change is, at least conceptually, simple. Activities that add greenhouse gases to the atmosphere—chiefly the use of fossil fuels—need to be changed or eliminated. Of course, not every alternative to fossil fuels will be equally beneficial. Technologies have to be evaluated for costs and benefits. One thing we know about wind turbines, for example, is that they can alter local temperatures by increasing the mixing of air at and above the surface.
Setting aside inevitable but ignorant claims that “wind turbines are just as bad as coal plants” (they aren’t by a longshot), it does make sense to think seriously about the effect turbines have on local temperature. Harvard’s Lee Miller and David Keith set out to fill some holes in our knowledge by simulating a less-than-implausible scenario in which the US produces all its electricity with wind power. At this scale, they wondered, what does the trade-off between fossil fuels and wind power look like?
Hexbyte – Tech News – Ars Technica | High-wind scenario
To find out, Miller and Keith turned to a high-resolution climate model of the continental United States. In the middle third of the country—where winds are higher—they placed enough virtual wind turbines to produce almost half a terawatt of electricity. This would meet 100 percent of current US demand.
The results of their simulation showed that the continental US got about 0.2°C warmer, on average, with the turbines in place. Within the wind-turbine-hosting region, that number was more like 0.5°C. That falls roughly in line with previous real-world measurements around wind farms.
The temperature change is larger at night and smaller during the day, because surface warming and convection driven by the Sun overwhelm the influence of the turbines. But when the air is calmer at night, the turbines help mix warmer air down toward the cooling surface. That’s why this is essentially an instantaneous but reversible effect. Turbines don’t add energy to the atmosphere—they just move some air around.
The researchers attempt to estimate the climate benefit of these turbines for comparison. But doing this in a truly apples-to-apples way is