Supplying Baseload Power and Reducing Transmission Requirements by Interconnecting Wind Farms

Abstract

Wind is the world's fastest growing electric energy source. Because it is intermittent, though, wind is not used to supply baseload electric power today. Interconnecting wind farms through the transmission grid is a simple and effective way of reducing deliverable wind power swings caused by wind intermittency. As more farms are interconnected in an array, wind speed correlation among sites decreases and so does the probability that all sites experience the same wind regime at the same time. Consequently, the array behaves more and more similarly to a single farm with steady wind speed and thus steady deliverable wind power.In this study, benefits of interconnecting wind farms were evaluated for 19 sites, located in the Midwestern United States, with annual average wind speeds at 80 m above ground, the hub height of modern wind turbines, greater than 6.9 m/s (class 3 or greater).We found that an average of 33% and a maximum of 47% of yearly-averaged wind power from interconnected farms can be used as reliable, baseload electric power. Equally significant, interconnecting multiple wind farms to a common point, then connecting that point to a far-away city can allow the long-distance portion of transmission capacity to be reduced, for example, by 20% with only a 1.6% loss of energy. 2Although most parameters, such as intermittency, improved less than linearly as the number of interconnected sites increased, no saturation of the benefits was found. Thus, the benefits of interconnection continue to increase with more and more interconnected sites.3

Electric power from offshore wind via synoptic-scale interconnection

“…It is a dimensionless quantity defined as energy output per year (in MWh) divided by the number of hours in the year times the nameplate, or rated, capacity (in MW). In simpler terms, CF is the average output (in MW a ) over the rated capacity (in MW) (14,22). For example, if a 5 MW turbine produces an average of 2 MW a throughout a year, its CF in that location is 0.40.…”

“…This is illustrated and discussed further in Fig. S3, using a probability distribution function like that used in some prior studies (2,14).…”

“…Several studies in the western United States and Europe have investigated the power leveling of aggregating geographically distributed wind farms (7)(8)(9)(10). They find improvement in the steadiness of the available power, even when the stations are relatively close (11,12) and a decrease in the number of low-or no-wind events (13,14). Additional stations decrease the variability of the summed wind power (8).…”

“…Additional stations decrease the variability of the summed wind power (8). Reduced variability means fewer very low power times, as well as fewer times of the highest power (14).…”

An Overview of Some Important Issues Related to Wind Energy Conversion System (WECS)

“…To provide guidelines for all stakeholders including utilities, independent power producers, users and equipment manufacturers, efforts are being made, both in Canada and internationally, to develop interconnection standards. Supported by Natural Resources Canada and Industry Canada, Electro-Federation Canada is developing Canadian guidelines for connecting small distributed resources to grids [8].…”