Wind Diversity Research Articles

Reliability/environmental impacts of wind energy curtailment due to ramping constraints

Wind is rapidly emerging as an important energy source in electric power systems. As wind penetration increases to relatively large scales, it becomes important in system planning to assess the capacity value and reliability impacts of wind resources, as well as the renewable energy utilization and the environmental benefits from them. Wind farms are at the top of the priority loading order, and all the wind energy generated is utilized to serve the load in scenarios where wind penetration is relatively low. In high wind penetration scenario, however, wind energy is occasionally spilled or curtailed due the limitations in operating reserve or ramping capability of the scheduled generating units. It becomes increasingly important to account for the wind curtailment scenarios and wind diversity effects when considering large scale wind power in capacity planning. Wind curtailment scenarios in different operating conditions have been analyzed in this paper by considering typical conventional generating units and their operating characteristics. Subsequently, an analytical technique for reliability and energy assessment is developed which incorporates the wind diversity and wind curtailment effects. The applications of the developed method to quantify the reliability, energy and environmental benefits of wind power are illustrated on a practical power system.

Dispersal traits linked to range size through range location, not dispersal ability, in Western Australian angiosperms

ABSTRACTAim We examine the relative importance of seed dispersal mode in determining the range size and range placement in 524 species from six focal plant families (Agavaceae, Euphorbiaceae, Malvacaeae, Sapindaceae, Proteaceae and Fabaceae (Acacia)).Location Western Australia.Methods Taxa were categorized by dispersal mode and life‐form and their distributions modelled using maxent. Geographical range size was compared amongst dispersal mode, life‐form and biome using phylogenetically independent contrasts. Geographical range placement was considered in a similar manner.Results Range size did not vary with dispersal mode (ant versus wind and vertebrate dispersal) or life‐form, and instead varied primarily as a function of the biogeographical region in which a species was found. Range placement, however, did vary among dispersal modes, with the consequence that diversity of wind‐ and ant‐dispersed plants increased with latitude while the diversity of vertebrate‐dispersed plants was more evenly distributed.Main conclusions For the taxa studied, range sizes were a function of the biogeographical region in which species were found. Although differences in range size may exist among species differing in dispersal modes, they are likely to be far smaller than differences among species from different biogeographical regions. The trait most likely to affect species geographical range size, and hence rarity and risks associated with other threats, may simply be the geographical region in which that species has evolved.