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HomeMy WebLinkAboutAK RENEWABLES - Shovel Creek Wind Resource Assessment Summary and Project Layout Shovel Creek Wind Resource Assessment Summary Wind energy production is affected by a number of different factors such as the site-specific wind resource, the inherent variability in the weather and climate, turbine design and performance characteristics, wind farm layout, various losses, as well as operational and maintenance approaches. Alaska Renewables is using a multi-pronged and industry standard approach to characterize and evaluate the wind resource at the Shovel Creek Wind site. This analysis is used for the assessment of project economics and the evaluation and optimization of its integration with the existing Railbelt system. The wind resources at the site were found to be excellent and will support high capacity factors and economic renewable energy generation. Meteorological Tower Campaigns In September 2022, Golden Valley Electric Association commissioned three new 60 m meteorological towers at the Shovel Creek Wind site. This effort was conducted with funding from the Alaska Renewable Energy Fund, and carried out in collaboration with Alaska Renewables, the developer. This meteorological campaign builds on prior wind resource campaigns at this site over a decade ago with shorter 30m towers. The results from that prior wind resource assessment campaign are summarized in the attached “Murphy Dome Vbar Data Report to GVEA 5-09.xlsx” worksheet. The new and ongoing campaign aims to obtain data suitable for project financing by capturing wind data from taller towers at multiple sites within the proposed project area. Figure 1. Shovel Creek meteorological tower #102 (60m) during installation in September 2022. The existing towers are equipped with at least 7 anemometers to measure wind speed in duplicate at three different heights above ground. Two wind vanes, two temperature sensors, one barometric pressure sensor and one relative humidity sensor are also present. Statistical data from all sensors is logged at 10 minute intervals. Figure 2. Preliminary Shovel Creek time series of wind speed from the 60m height above ground at site #101. Figure 3. Preliminary Wind Rose from the Shovel Creek meteorological tower observations. Figure 4. Cost of Energy Optimized Shovel Creek project layout for a maximum 214.2MW project size. Our modeling optimizes turbine locations and supporting infrastructure alignments in order to minimize the cost of energy for the project. The modeling takes into account a wide range of factors including but not limited to the spatial distribution of the wind resource (mean wind speeds are indicated by the underlying colors in the figure above), wake losses induced by other turbines, and the total cost of roads, collector, and transmission system. Shown are the turbine rotor areas (black points), minimum turbine offsets (ovals). The three meteorological tower sites are displayed as green circles. The thick gray line is the existing Murphy Dome Extension Road. Wind Resource Modeling A 200m resolution wind resource grid based on downscaled climate and weather models was obtained from UL. This wind resource grid provides wind speeds, directions, and their frequencies across the entire Shovel Creek Wind Energy Site. This resource grid was utilized in UL’s OpenWind software to optimize the site layout including turbine placement, roads, and electrical collector and transmission lines. The resulting layouts are unique for each project capacity because the software tool attempts to maximize energy production while minimizing turbine wake loss effects and capital costs such as road and cable lengths. Once the project layout and cost of energy was optimized, the wind resource grid was used to calculate the net capacity factors and net energy production from each individual turbine while accounting for wake effects and other losses. The results are presented in Shovel_Creek_standard_energy_capture_report.xlsx In addition to the climatological wind resource grid, we also analyzed an hourly, 21-year long historical (2000-2020) wind speed time series for theShovel Creek site in order to generate a wind generation time series and quantify the expected monthly and interannual variability of expected wind energy production from the site. This ERA5 climate and weather reanalysis data product combines model data with historical weather observations from across the world into a globally complete and consistent dataset using the laws of physics. To account for these terrain effects, we scaled up the wind speed time series data to the average wind speeds obtained from the high resolution terrain-resolving wind resource grid from UL (described above). Table 1. Shovel Creek average wind speeds at turbines, net capacity factors, turbine array wake losses, and annual net energy production estimates for each of the proposed project capacities and their associated layouts. The net capacity factor and net annual energy production estimates account for the modeled wake losses for each of the different project layouts as well as the other loss factors specified in the Shovel_Creek_standard_energy_capture_report.xlsx. Site Capacity with GE 3.4- 140 (MW) Mean free wind speed at turbines (m/s) Net Capacity Factor (%) Array Efficiency % Total Losses Net Energy Production (GWh/yr) Shovel Creek 214 7.41 36.30 95.8 18.29% 680.5 109 7.31 35.76 96.2 17.97% 341.4 71 7.29 35.96 96.4 17.77% 223.6