“In a wind-thermal system, production variations from the intermittent character of wind power results in an increase in system costs and a decrease in the efficiency of wind power as a means to reduce CO₂-emissions from the system. This effect gets increasingly pronounced with increased levels of wind power grid penetration and is due to the adjustment in production pattern of the thermal units to the variations in wind power production. As wind power grid penetration increases, the conventional units will run more at part load and experience more frequent starts and stops. Also, wind power may need to be curtailed in situations where the costs to stop and restart thermal units are higher than the difference in running costs of wind power and the thermal units. Thus, variations in wind power reduce the possibility of the power system to lower CO₂-emissions by adding wind power capacity to the system.”
—“Large scale integration of wind power: moderating thermal power plant cycling” by Lisa Göransson and Filip Johnsson, Wind Energy 2011; 14:91–105
Olaf Errwigge (Facebook) —
There is no argument that burning fossil fuel to generate electricity releases CO₂ into the atmosphere, or that using the wind to generate electricity does not. But it does not follow that adding wind to the grid reduces CO₂ emissions from other sources: Where there is little hydropower (no CO₂ emissions) to balance the highly variable wind, fossil fuel–fired generators are forced to work less efficiently, ie, with more emissions per unit of electricity generated. Furthermore, the best “balancing” plants for wind are open-cycle natural gas–fired turbines (OCGT), which can respond quickly enough to compensate for the continual changes of wind generation. But combined-cycle natural gas–fired turbines (CCGT) are substantially more efficient efficient, such that wind + OCGT may not represent lower emissions than CCGT alone. Thus, wind power’s manufacture, transport, and maintenance would indeed contribute to increased CO₂ emissions. And there is no benefit at all to weigh against its other adverse impacts on the environment, wildlife, and human neighbors.
Result: Wind + fossil fuel generation does not necessarily mean lower CO₂ emissions, particularly in the comparison of wind + open-cycle gas (necessary to quickly respond to wind’s continually variable generation) vs. the much more efficient combined-cycle gas alone.
And, of course, where there’s hydro, that’s the preferred source to ramp back as the wind rises: no CO₂ involved at all.
With virtually no benefits, wind power’s many adverse impacts – on the environment, wildlife, and human neighbors – not to mention its financial cost and the carbon and materials footprint of its manufacture, transport, and maintenance – are impossible to justify.
Also see: “Why wind power does not substantially reduce emissions”
