HomeMy WebLinkAboutUtility-Scale Railbelt Wind Final Design and Permitting Project Shovel Creek Wind Resource Assessment Summary - Dec 2022 - REF Grant 7015021Shovel 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
Murphy Dome Vbar Data
Report to GVEA 5-
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
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