Wind Power

Wind Power

4/13/2014

 Renewable energy is trumpeted as the future and savoir of industrial society and our future.  Wind and solar energy will be the cornerstone of society’s future.

But will they be?

Wind power’s advocates claim its electricity will be affordable, renewable, sustainable, reliable, available and will not create any carbon dioxide emissions, thus preventing global warming.  Can wind energy fulfill these promises?

Wind energy is very dilute, so large wind turbines and land areas are required. Standing 300 to 500 feet tall, each turbine requires 10 times its blade diameter of surrounding clear land to capture wind energy and prevent damage to adjacent wind turbines.

The amount of energy extracted from the wind is a function of the cube of the wind speed. This is a vital aspect of wind turbine design.  Wind turbines are designed to a specific wind speed, nominally 25 mph. A decrease in wind speed to 20 mph decreases power by almost 50%. Below 15 mph there is insufficient energy to turn the turbine blades and generate electricity.  

The maximum power generated occurs at the optimum wind speed and is known as the Nameplate power. The Nameplate power output is repeated endlessly in the press as the continually generated power.  However, how often does a wind turbine see its optimum wind speed?  Not very often. 

The difference between Nameplate and actual power produced is known as capacity and is ignored or briefly mentioned in the press.  Due to variable wind speeds, wind turbines operate at a 20-35% capacity.  This means for a 1000 MW (megawatts) wind farm only 350 MW is available at any time. Capacity affects electricity affordability because money spent to produce power does not generate power.  

Is wind power reliable and available? Does wind produce carbon dioxide emissions? These issues will be discussed in future blogs?