WIND ENERGY TECHNOLOGIES OFFICE
Case Study: How Wind Energy Became Integral to the Modern Grid

In the 1980s, the electric power community considered wind energy a mere curiosity. Over the next 40 years, the U.S. Department of Energy's (DOE) Wind Energy Technologies Office (WETO) worked to establish the electric sector's acceptance of wind energy, enabling it to become a significant contributor to the nation's energy portfolio. 

WETO, as well as others in the federal government and the private sector, have worked to provide educational opportunities for personnel at utilities to learn about wind, helping to transform it from a minor contributor to the grid to 10% of U.S. energy generation today.

In 1989, WETO partnered with the Electric Power Research Institute and several U.S. electric utilities to form the Utility Wind Interest Group (UWIG). At the time, wind was considered an unconventional, weather-driven, variable power source. However, over the next decade, UWIG offered utilities a forum to share their information about and experiences with wind power and learn from leading experts in wind energy integration at national labs.  

By the early 2000s, UWIG had become a go-to resource to identify, quantify, and address technical issues that arose when wind power was integrated into the traditional electric power grid. UWIG also allowed members of the utility industry to provide feedback to WETO which provided continuous financial and technical support for UWIG.  

Early Utility Concerns Shift from Wind Energy Costs to Operating Costs 

In the early 2000s, utilities shifted their concerns from cost to wind energy's variability and whether its corresponding uncertainty would increase system operating costs. 

This concern led to one of the first grid integration studies, which UWIG conducted from 2001 through 2003. The study was funded by Xcel Energy with support from WETO and examined how Minnesota's grid would respond with a significant amount of wind energy contributing to its electricity-generating mix. Experts from DOE's National Renewable Energy Laboratory (NREL) and Oak Ridge National Laboratory (ORNL) helped define the study's methodology.  

The study estimated that the financial impact of installed wind energy generation on system operating costs was less than $2 per megawatt-hour.  

These results surprised many in the electric utility industry and helped pave the way for subsequent wind energy expansion in many utility systems. The results encouraged utilities and state governments in Minnesota, Colorado, Nevada, Arizona, Nebraska, Texas, California, and other states to evaluate the feasibility of higher contributions of wind power in their own systems which included higher levels of wind energy than the UWIG study and increasingly larger geographic areas.  

Regional Analyses Show Systems Can Handle High Wind Energy Penetration 

Results from these early studies concluded that as larger geographical areas were deemed viable for wind energy, the system-operational costs arising from wind energy's variability decreased a phenomenon that is now known as geographic diversity. This phenomenon indicates that the variability of energy output decreases as wind power plants cover a larger geographic area. For example, a single wind turbine's output is inconsistent, a 100-megawatt (MW) plant has more consistent energy output, and three 200 MW wind plants spread across a region have more ideal output due to geographic diversity, meaning more wind in one area could make up for less wind in another.  

This led to integration studies by independent system operators and regional transmission organizations that examined larger regions of the nation. 

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