Wind on the Wires1 - Smart Grid (R) Evolution: Electric Power Struggles - page 132

benefits differs across the scenarios and over time. In this chapter we focus on the critical
interactions and co-development of large-scale wind power and smart grid to highlight
evolving creative tensions of smart grid development embedded in larger system-wide
change. We also explore how polices used to promote wind power are shaping smart grid
development. The Texas case highlights how policies to encourage renewable electricity
generation have led to the development of new transmission lines and also changed electric
grid operations. In the Upper Midwest and Germany, transmission lines to connect remote
wind sites to load centers often cross multiple jurisdictions, disrupting traditional siting
and cost allocation practices. These case studies explore the shifting alliances and tensions
across all three systems. In this chapter we explore the question of who benefits and who
looses when large-scale wind power development and smart grid are linked.
We begin the chapter by reviewing the potential of large-scale wind power, including
a brief historical perspective on the coevolution of wind power technology and electricity
system development beginning in the 1800s. This is followed by the Texas, Upper
Midwest, and German case studies. We conclude the chapter by discussing the
commonalities among the three cases.
6.2 Wind Power in Context
Globally, wind power is increasing rapidly; with over 310,000 MW of installed wind
capacity by the end of 2013, wind power has become the fastest growing energy
technology. This rapid growth in wind power highlights the transformation of the
technology from a boutique energy source to a critical technology shaping grid
management and electricity markets.
Wind is created from the rotation of the earth, the shape of the earth surface, and the
uneven heating of the earth's atmosphere. These factors combine to form different wind
patterns across the earth that can be harnessed to push turbine blades, which then spin the
rotors driving a shaft to generate electricity. Wind power is a “variable resource,” only
producing electricity when the wind is blowing. Wind turbines generate electricity above a
minimum cut-in speed, approximately 7-10 miles per hour. Most turbines produce power
at full capacity at speeds of 25-30 miles per hour (the rated speed) and cut out if the
wind speed is above 45-80 miles per hour to protect the turbines if the wind is too strong.
Wind turbine technology has been improving to expand the cut-in and cut-out operating
range which increases wind power's capacity factor, or percentage of time the turbine is
operating at its rated capacity. Wind turbine capacity factors vary because they depend
on both the technology and the site-specific wind resource. Wind power capacity factors
have been steadily increasing, from less than 18 percent in the mid-1990's to current levels