Wind energy leads to a more reliable and resilient power system

Technological advances have not only reduced the cost of wind energy, but also increased wind’s contributions to power system reliability. Last year, wind and solar made up nearly 75 percent of new electric generating capacity that came online in America, and in some regions wind energy now reliably provides 20 percent or more of total electricity generation. Thanks to the use of power electronics and other advanced technologies, wind plants can now provide all reliability services as well or better than conventional power plants.

That means opponents are turning to increasingly far-fetched criticisms. The latest comes from a long-time anti-renewable energy group, the Manhattan Institute, with a well-known history of special interest funding and skewed attacks on clean energy. So it’s no surprise their latest attack parrots a false claim about cybersecurity that was first debunked two years ago.

Their report leads with sky-is-falling rhetoric attacking renewable energy, but the text contains no substantive discussion of any link between renewable energy and cybersecurity concerns, likely because none exists. Surveying the hundreds of pages of documents from the nation’s electric reliability regulators and other experts outlining the top cyber-security concerns on the grid, renewable energy resources do not appear to ever be singled out as a primary area for concern.

The Reality: Wind energy builds a more resilient power system

The reality is that diversifying our energy mix with wind energy makes the power system more resilient, and better able to withstand both intentional and unintentional disruptions. Aside from the inherent value in having a more diverse energy mix, wind plants have technical attributes that make them better contributors to power system resilience than conventional power plants in many regards.

Many recent electric reliability events in the U.S. and around the world have been caused by large conventional power plants unexpectedly going offline when the power grid experiences a voltage or frequency disturbance. While these grid disturbances are typically caused by unintentional events, like a conventional power plant or a transmission line failing, the main impact of an intentional attack would also be a voltage or frequency disturbance that propagates across the power system.

Fortunately, wind plants far exceed the ability of conventional power plants to “ride through” voltage and frequency disturbances. In fact, since 2005 wind plants have met a far more stringent standard for voltage and frequency ride-through than conventional power plants, and some owners of conventional generators blocked efforts to enact a standard that would bring conventional generators up to the same ride-through requirements as wind generators, as their plants cannot meet the wind plant requirement. All modern wind plants have this capability because sophisticated power electronics electrically isolate the wind turbine from the grid, allowing the turbine to remain online when a conventional power plant would have been forced offline.

These power electronics also make wind turbines better than conventional power plants for stabilizing the grid following a disturbance. Wind plants can provide far faster and more accurate voltage and frequency regulation than conventional power plants, allowing the power system to more quickly return to normal following a disturbance. Wind’s reliability capabilities are discussed in more detail in the table at the end of this report.

Wind plant owners and operators employ some of the most sophisticated cyber-security defenses in use in any industry. All modern power plants of any fuel type are connected to grid operators and plant operators by supervisory control and data acquisition (SCADA) communications systems, and wind plants are no different. Almost all wind plants are utility-scale installations that are connected to the high-voltage power system through a single plant-level power substation, so they are no different from any other type of power plant in that regard.

Power plant communications systems and control centers, for wind plants and other types of power plants, are subject to strict security standards governed by the two entities responsible for electric reliability in the U.S., the Federal Energy Regulatory Commission and the North American Electric Reliability Corporation. These standards evolve over time, and now include strict requirements for cybersecurity. For any type of power plant, information sent over these SCADA communications systems is protected using state-of-the-art encryption. For wind plants, like any other power plant, this information is typically sent to the plant operator’s national or international control center, which also employs strict security measures that are comparable to those used by grid operators.

Wind and other power plant owners already have a strong financial incentive to ensure that these communication networks are secure. In addition to the obvious economic harm that a hacker could do to their own plant through sabotage, information about wind plant output and wind turbine status is extremely commercially sensitive as it could be used by any competitor in the energy sector for competitive advantage.

Moreover, given the small size of individual wind plants, wind energy would be a poor choice for a hacker intent on disrupting the power system. Based on their size alone, large conventional power plants pose a much greater risk for an attack aimed at causing a destabilizing loss of generation, as demonstrated by the fact that most blackouts and major electric reliability events that have occurred around the world have been at least partially caused by the loss of large conventional generation or its supporting transmission infrastructure, and none caused by the loss of renewable energy.

Stronger transmission equals a stronger grid

The Manhattan Institute’s report also misguidedly raises security concerns about building a stronger transmission system. In reality, grid upgrades are being made primarily because they improve electric reliability, in addition to allowing the more efficient transmission of low-cost energy to customers. Most reliability problems that occur today are at least partially caused by weakness and congestion on the transmission system, and grid operators and other experts are unanimous in explaining that transmission upgrades make the power system more reliable, not less.

The following table summarizes how wind plants’ provision of essential reliability services compares favorably to that of conventional resources, with links providing citations to reports from reliability regulators and other experts:

Reliability service Wind Conventional generation 
Ride-through Excellent voltage and frequency ride-through, meeting FERC Order 661A requirements–Power electronics electrically separate wind turbine generators from grid disturbances, providing them with much greater ability to remain online through disturbances  -Many cannot match wind’s capabilities or meet Order 661A ride-through requirements
Reactive and voltage control – Wind turbine power electronics provide reactive and voltage control equivalent to that of conventional generators– Power electronics can provide reactive power and voltage   control even when the wind plant is not producing power  -Conventional generation provides this service.
Active power control Can provide extremely fast response in seconds, far faster than conventional generation– Like other generators, wind will provide this response when it is economic to do so- Xcel Energy sometimes uses its wind plants to provide some or all of its frequency-responsive automatic generation control 

 

– Like wind, many baseload generators do not provide active power control for economic reasons, though they technically can
Frequency response Adding wind can help system frequency response by causing conventional generation to be dispatched down-Wind can provide frequency response, but it’s typically more costly for it to do so than for other resources as it requires curtailing wind generation in advance  Changes in conventional generator operating procedures have greatly reduced frequency response– Only 70-75 percent of generators have governors that are capable of sustaining frequency response for more than one minute, and about half of conventional generators have controls that may withdraw sustained frequency response for economic reasons– “Only 30 percent of the units on-line provide primary frequency response. Two-thirds of the units that did respond exhibit withdrawal of primary frequency response.” So, “Only 10 percent of units on-line sustain primary frequency response.” 
Inertial response Can provide with no lost production by using power electronics and the inertia of the wind turbine rotor; this capability is commercially available but not widely deployed because there is no payment for any resource to provide this service  -Conventional generation provides this service.
Increases need for operating reserves, integration cost Very small impact on total reserve need and integration cost -Contingency reserve needs and costs are quite large

 

Further documentation of wind’s reliability services contributions is available from the following NERC reports:

  • NERC recently noted, “This issue does not exist for utility-scale wind energy, which offers ride-through capabilities and other essential reliability services.”
  • NERC stated “Modern wind turbine generators can meet equivalent technical performance requirements provided by conventional generation technologies with proper control strategies, system design, and implementation.”
  • Regarding voltage and reactive power control, NERC has noted “As variable resources, such as wind power facilities, constitute a larger proportion of the total generation on a system, these resources may provide voltage regulation and reactive power control capabilities comparable to that of conventional generation. Further, wind plants may provide dynamic and static reactive power support as well as voltage control in order to contribute to power system reliability.”
  • NERC also recently noted that “… by causing conventional generators to have their output dispatched down, wind and solar generation can increase generator headroom and, therefore, the amount of total frequency response being provided.” The National Renewable Energy Laboratory also documented that “Wind power can act in an equal or superior manner to conventional generation when providing active power control, supporting the system frequency response and improving reliability.”

So, once again the Manhattan Institute is misleading readers. The truth is wind power diversifies our electricity mix, and along with improved transmission, helps create a stronger, more reliable system.

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