摘要:Future climate change is expected to alter the spatial and temporal distribution of surface
wind speeds (SWS), with associated impacts on electricity generation from wind
energy. However, the predictions for the direction and magnitude of these changes
hinge critically on the assessment methods used. Many climate change impact
analyses, including those focused on wind energy, use individual climate models
and/or statistical downscaling methods rooted in historical observations. Such
studies may individually suggest an unrealistically high level of scientific certainty
due to the absence of competing projections (over the same region, time period,
etc). A new public data archive, the North American Regional Climate Change
Assessment Program (NARCCAP), allows for a more comprehensive perspective on
regional climate change impacts, here applied to three wind farm sites in California. We employ NARCCAP regional climate model data to estimate changes in SWS expected
to occur in the mid-21st century at three wind farm regions: Altamont Pass, San Gorgonio
Pass, and Tehachapi Pass. We examined trends in SWS magnitude and frequency
using three different global/regional model pairs, focused on model evaluation,
seasonal cycle, and long-term trends. Our results, while specific to California,
highlight the opportunities and limitations in NARCCAP and other publicly
available meteorological data sets for energy analysis, and the importance of using
multiple models for climate change impact assessment. Although spatial patterns in
current wind conditions agree fairly well among models and with NARR (North
American Regional Reanalysis) data, results vary widely at our three sites of interest.
This poor performance and model disagreement may be explained by complex
topography, limited model resolution, and differences in model physics. Spatial
trends and site-specific estimates of annual average changes (1980–2000 versus
2051–71) also differed widely across models. All models predicted changes of < 2% at each site, but the direction of the change varies. However, decreases of < 2% in resources at Altamont Pass are agreed upon by each NARCCAP model used. This lack
of model agreement suggests uncertainty in future changes, and a potentially high degree of
risk for future investors in wind-generated electricity. More broadly, our study highlights
the need for multiple calculation approaches to help distinguish between robust and
method-dependent results.