Wind energy contributes to a reliable power system

Wind power makes important contributions to the country’s electricity mix and helps keep the lights on in a cost-effective manner for millions of American families and businesses. Today, six states generate over 20 percent of their electricity using wind, and overall 14 states generate at least 10 percent of their electricity with wind power.

The reality is no source generates electricity 100 percent of the time. For example, during Hurricane Harvey coal yards in Texas flooded, forcing those plants offline, and nuclear plants along the Florida coastline had to shut down due to concerns over storm surges. Likewise, coal piles froze and natural gas pipelines failed during the 2014 Polar Vortex due to the extreme cold, while wind turbines kept turning, saving Great Lakes and Mid-Atlantic consumers over $1 billion in just two days.

Grid operators have a century of experience dealing with changes in electricity supply and demand. Factories, air conditioners and appliances turn on and off in waves, varying by time of day and season. Major spikes occur from events as simple as halftime during a football game, when millions of refrigerator doors open.

Changes in wind output can be predicted up to 48 hours in advance, giving grid operators ample time to adjust, whereas sudden outages at conventional plants are much more costly an unexpected. Wind farms built since 2014 have also averaged capacity factors exceeding 40 percent, close to average capacity factors for coal and some types of natural gas plants.

Grid reliability is strong and increasing

Electricity markets, and the multiple layers of regulatory checks already in place at the state, regional, and federal level, are successfully working to ensure that electric reliability remains strong. As the North American Electric Reliability Corporation (NERC) and other experts have concluded, ongoing and planned power plant retirements do not pose a reliability threat. The CEO of NERC has testified to the Federal Energy Regulatory Commission that “the state of reliability in North America remains strong, and the trend line shows continuing improvement year over year.”

The chart below, compiled from grid operator data and included in NERC’s Long-Term Reliability Assessment, shows that all regions greatly exceed their targeted level of power plant capacity through at least 2021. Moreover, the regions with the most coal plant retirements, PJM and SERC, exceed their capacity reserve margins by double digits even under the most conservative planning standard.

Planning Reserve Margins in 2021
Markets are key for grid reliability

Markets for grid reliability services – commonly called ancillary service markets – are the most efficient way to ensure reliability across the grid. Many resources are capable of providing the required services, including wind and solar, and markets help to ensure the most economic resources are selected to deliver these services. Wind farms may not always be the most economic resource, just as coal and nuclear plants do not typically provide flexibility or other reliability services. And that’s fine – the market is working.

Wind continues to increase its participation in ancillary services markets. Technology advances like smart inverters and fast controls expand the reliability services wind can cost-effectively supply to the market. Advanced power electronics and output controls enable wind to provide automatic generation control, primary frequency response, and synthetic inertia, among other services. The chart below provides a concise comparison of the ability to provide grid reliability services across different generation technologies.

Source: Milligan Grid Solutions