Worldwide, several power systems already are coping with large amounts of wind power – up to 20% of their annual energy consumption, and sometimes more than 50% of off-peak power production. Wind inherently is variable, difficult to accurately predict, and frequently anti-correlated with electricity load. The often remote location of wind resources relative to load centers requires cost-effective transmission. Thus, integrating significant amounts of wind generation presents a unique challenge to the power system, requiring additional flexibility while simultaneously imposing a decreased capacity factor on conventional generating units.

The system impacts of wind power integration are highly variable, primarily depending on wind penetration, existing transmission infrastructure, and system operating flexibility. High penetration of wind power is expected to produce power system impacts that can be reduced through smarter power plant interconnection, transmission and resource planning, and system and market operations.

The need for additional system flexibility -- that is, the ability of the system to respond to variability and uncertainty -- principally is determined by wind-related features, with wind penetration being the single greatest factor. Studies and experience to date have shown that most power systems can, on an energy basis, reliably accommodate up to 10% wind penetration, with only minor cost and operating impacts.[5][12] The cost to provide this system flexibility (as opposed to the costs to actually connect wind to transmission and distribution networks) is best described as the additional costs induced by balancing the variability and uncertainty of wind, and is a function of the existing power system, plus any new investment required. A 2009 International Energy Agency (IEA) study, which compared the wind integration costs from studies across Europe and North America, cited a cost range of 0-4.0€ /MWh, or about 0-$5.63/MWh (see Figure 1.[5])

With regard to moving wind energy to load, transmission issues are particularly challenging. From planning to permitting, from capital cost estimation to cost allocation, there is no clear indication how and whether sufficient transmission will be constructed to tap our vast, remote, domestic wind resources...(Read more...)