The Utility Wind Integration Group (UWIG) has released of an assessment on the impact and issues related to the integration of wind energy into existing utility power systems. The key conclusion from the group is that they don’t see any fundamental technical barriers to wind energy penetrations of up to 20 percent of system peak demand.
According to UWIG, “Utility Wind Integration State of the Art” is a summary of the best information available from around the world on what is known about integrating wind power plants into electric utility systems. UWIG produced the report in cooperation with the American Public Power Association (APPA), Edison Electric Institute (EEI), and National Rural Electric Cooperative Association (NRECA).
The report examined wind energy’s impacts on the operating costs of the non-wind portion of the existing power system and the impacts on the system’s electrical integrity. “The consensus view is that wind power impacts can be managed with proper design and operation of the system. There is still a lot of work to be done to get the message across and get everyone up the learning curve, but we are well on the way,” said UWIG executive director Charlie Smith.
Some of the conclusions from the UWIG assessment:
- On the cost side, at wind penetrations of up to 20% of system peak demand, system operating cost increases arising from wind variability and uncertainty amounted to about 10% or less of the wholesale value of the wind energy. These incremental costs, which can be assigned to wind-power generators, are substantially less than imbalance penalties generally imposed through Open Access Transmission Tariffs under FERC Order No. 888. In many cases, customer payments for electricity can be decreased when wind is added to the system, because the operating-cost increases could be offset by savings from displacing fossil fuel generation.
- In areas with limited penetration, modern wind plants can be added without
degrading system performance. System stability studies have shown that modern wind plants equipped with power electronic controls and dynamic voltage support capability can improve system performance by damping power swings and supporting post-fault voltage recovery.
- The addition of a wind plant to a power system increases the amount of variability and uncertainty of the net load. This may introduce measurable changes in the amount of operating reserves required for regulation, ramping and load-following. Operating reserves may consist of both spinning and non-spinning reserves. In two major recent studies, the addition of 1,500 MW and 3,300 MW of wind (15% and 10%, respectively, of system peak load) increased regulation requirements by 8 MW and 36 MW, respectively, to maintain the same level of NERC control performance standards.
- Fluctuations in the net load (load minus wind) caused by greater variability and uncertainty introduced by wind plants have been shown to increase system
operating costs by up to about $5/MWH at wind penetration levels up to 20%. The greatest part of this cost is associated with the uncertainty introduced into day-ahead unit commitment due to the uncertainty in day-ahead forecasts of real-time wind energy production.