Presentation on urban wind in California by Case van Dam, UC Davis. The presentation was part of the Urban Wind Roundtable at the Consulate General of the Netherlands in San Francisco, March 16, 2011.

1. Research on wind
power in the built
environment
C.P. (Case) van Dam,
Bruce White, Scott Johnson,
Daeseong Kim, Henry Shiu, Matt Seitzler,
Rob Kamisky, Charles Turner
Urban Wind Roundtable
San Francisco
March,16 2011
1
Outline
! UC Davis/CWEC overview
! Atmospheric Wind Tunnel
! UC Davis projects
1. San Francisco wind resource study
2. San Francisco building-integrated wind power
3. Rooftop wind turbine demonstration site
4. California wind maps web tool
! Concluding Remarks
! DOE Built-Environment Wind Turbine RD&D Roadmap
Source: Mayda
2

2. UC Davis Energy Institute
! Established Fall 2007 as home to major UC Davis energy
research centers and education programs
! Campus-wide & administered through Office of Research
with multi-college support
! Created to focus and bring together campus strengths in
energy research, education, and outreach, and to build new
interdisciplinary programs and capabilities
! Strategic planning for effective energy transformation
! Approximately 150 faculty members across campus
California
Renewable
Energy
Collaborative

3. California Wind Energy Collaborative
Mission Statement:
Support the development of safe,
reliable, environmentally sound, and
affordable wind electric generation California
capacity within the state of California Energy
by managing a focused, statewide Commission Industry
program of scientific research,
technology development & Public
deployment, and technical training. Academia
programs CALIFORNIA
WIND ENERGY
COLLABORATIVE
Federal, state, and Government and
local government industry research
agencies labs
! A partnership of the California
Energy Commission and the Education Inter-agency,
University of California & Inter-sector
! Established in March 2002 Outreach Coordination
! http://cwec.ucdavis.edu/
Engineering
! info@cwec.ucdavis.edu
Research
CWEC Research Focus
CALIFORNIA WIND ENERGY COLLABORATIVE
Coordination Research Training
! Recent projects:
" Conversion Technology
Development
! Blunt trailing edge airfoils (DOE, SNL)
Resource Assessment
!Wind turbine wake effects
! Rotor analysis (DOE, SNL, TPI,
!Complex terrain
Conversion Technology Clipper)
!Shear / wind patterns at tall heights
!Offshore
Blades and Rotors ! Rotor passive load control, STAR
!Computational design and analysis
!Long range forecasting
!Wind tunnel analysis (DOE, SNL, K&C)
!Improve accuracy of wind assessment
in small wind applications
!Active and passive load control
!Development of improvements to blade
! Rotor active load control (SNL)
!Wind assessment in urban
environments
design and analysis methods
!Design and analysis of alternative
! Load limiting algorithm (CEC/EISG,
Permitting configurations NREL)
!Research to support the development
of safe, fair permitting criteria
Emerging Technologies
!Offshore " Development
!Evaluation of emerging technologies
! Wake effects (CEC)
Grid Integration ! Forecasting (CEC, EPRI)
!Application of forecasting to day-ahead
Operation
! Turbine setback (CEC)
and hour-ahead energy markets
!Forecasting of power generation ramps
Asset Management/Optimization for
Reliability
" Grid Integration
!Impact of distributed generation on
distribution networks
!Performance analysis and health
monitoring
! IAP (CEC)
!Support future integration studies
!Applications and impacts of energy
!Condition monitoring
!Forecasting for maintenance scheduling
! Ramping, variability of windplants
storage
and plant/turbine operations (SMUD)
Anemometer Calibration ! Value of wind forecasting (CAISO)
!Expand wind tunnel calibration
capabilities
!Anemometer sensitivity to complex,
" Operation
real-world flows: inclined flows,
turbulence, effects of nacelle and
! Anemometer calibration (CEC, Otech)
mounting fixtures ! Performance analysis of windplants
(SMUD)

4. Atmospheric Boundary Layer Wind Tunnel
at UC Davis
! Tunnel specs
! Open-return type
! Overall length = 21.3 m
! Test section = 2.44m x 1.66m x 1.18m
! Typical model scale = 1:600
7
Environmental Fluid Dynamics Lab at UC Davis
! AIR QUALITY & PLUME DISPERSION
" LLNL, LLBL & Industrial Safety Studies
" Sports Stadium Analyses (Pac Bell, etc.)
! LARGE SCALE ENVIRONMENTAL
STUDIES
" Owens (dry) Lake Mitigation Studies
" Martian Dust Storm Analysis (NASA)
! PEDESTRIAN LEVEL WIND STUDIES
" San Francisco, Oakland & L.A. Studies
" Getty Museum Wind Analysis
! WIND ENERGY APPLICATIONS
" Altamont Wind Farm Forecasting Studies
" Turbine Siting in Complex Terrains
" Urban Wind Energy Studies
Source: Mayda
8

5. Physical Modeling of San Francisco Wind Project
1
Power Resources (1)
! Objectives:
" Gain further understanding of wind resource in urban
environments (San Francisco)
! Testing Scheme:
" Pick sites for study
! Taller than surrounding buildings, conventional shape
" Perform wind tunnel tests
! 3-4 predominant wind directions per site
! Take measurements on building for each wind direction
" Obtain full scale winds from wind-tunnel data
" Estimate energy production for various turbines
! Integrate data with turbine power curves
9
Physical Modeling of San Francisco Wind Project
1
Power Resources (2)
! Approach:
" Use ABLWT to simulate
wind flow over cityscapes,
San Francisco, and complex
terrain
" Measures mean wind
speeds and turbulence
intensities near surfaces
" Measurements performed
for each wind direction of
significance
Source: Mayda
10

6. Physical Modeling of San Francisco Wind Project
1
Power Resources (3)
! Wind Data:
" Anemometer data from old Federal
Building
! H = 40.2m (132 ft) above ground
" Data from 1945 – 1947
! Used because of completeness and
representative of typical San Francisco
wind conditions (White, 2006)
" Average wind speed was 5 m/s (11 mph)
! Fluid parameters taken into consideration when modeling flow in
wind tunnel (see Appendix)
! Free-stream wind speed in wind tunnel = 3.8 m/s
" Data collected from wind tunnel experiments
! Wind speed ratio (R-value)
! Turbulence intensity value
Source: Mayda
11
Physical Modeling of San Francisco Wind Project
1
Power Resources (4)
! Test Sites:
" 3 existing (The Fox Plaza, Bank
of America, CSAA buildings)
" 2 potential future developments
Courtesy Environmental Science Associates, 2006
! Measurement Locations:
" Numerous points tested
" Building faces, corners, rooftop
perimeter & profiles at specific
locations above the roof.
Source: Mayda
12

7. Project
Sample of Results – Fox Plaza 1
! Wind-tunnel data used to predict annual average wind power
densities for each measurement location on each building:
• “poor” (white dots): Pannual average/area: less than 100 W/m2
• “good” (green dots): Pannual average/area: between 100-700 W/m2
• “great” (yellow dots): Pannual average/area: greater than 700 W/m2
An example of annual average wind power densities in graphical form for each point is shown
above. The building’s points are shown in four views above. Similarly-styled results were obtained
for all buildings in this study.
**Manwell, J. F., J. G. McGowan, A. L. Rogers. Wind Energy Explained: Theory, Design and Application. San Francisco: John Wiley & Sons Ltd, 2003.
Project
Project Outcomes 1
! Wind tunnel tests showed the best place for a turbine is on
or above the roof level.
! However, also showed that each building had its own
specific set of wind characteristics.
" Therefore, testing on a specific site might be necessary
before installing a turbine.
Recommendations
! Conduct more wind tunnel tests:
" If more buildings are tested, might be possible to generalize
wind characteristics of certain types of cityscapes.
! Analyze impact of turbulence levels on turbines
! Compare wind tunnel tests with field anemometers
Source: Mayda
14

8. Project
2
Building Integrated Wind Energy Project
Full-scale 1:150 scale wind tunnel model
15
Project
2
Building Integrated Wind Energy Project
Full-scale 1:150 scale wind tunnel model
16

9. Project
2
Building Integrated Wind Energy Project
17
Building Integrated Wind Energy Project Project
2
Wind Tower Detail
18

10. Small Turbine Demonstration Site at UC Project
3
Davis
! Bergey XL1 on roof of Bainer Hall
! Used as a demonstration site…
" Collecting meteorological data and
performance data
" Undergraduate senior design research
projects (redesign blade set)
" Basis for providing general wind energy
information (group tours, interested
students)
19
Project
Roof-Mounted Turbine Power Curve 3

11. Project
GIS Map Tool Interface 4
! Effort funded by California Energy Commission
! Develop an online wind assessment tool for general public
" CEC/PIER funded development of detailed wind maps for California
! Maps provide annual wind power and speed at several heights above the
ground
! Maps generated by AWS TruePower
! Maps are available in pdf format from CEC website
! Difficult to pinpoint locations and determine wind speed at specified location
and height
! CEC has GIS-based version of wind maps
! Disadvantage of GIS-based wind maps is that specific software
(ArcExplorer) is needed to access information
" Develop a web-based version of GIS-based wind maps
! Combine GIS-based wind maps with Google maps
! Allow users to click on or search for a particular location to view wind data
information
! Able to get wind data as function of height
Source: Mayda
21
Project
California Wind Maps 4
! Maps of annual average
wind speed and power have
been produced for California
! Maps have a grid resolution
of 200 m
! Actual winds at a specific site
for the turbine can vary
significantly from the map
! Maps are good tools for
guiding and estimating but
do not replace Micro-siting
Wind energy density at 50 meters above ground.
California Energy Commission.
http://www.energy.ca.gov/maps/wind.html

12. Project
GIS Map Tool Interface 4
Source: Mayda
23
Concluding Remarks
! San Francisco is an excellent location to
study wind in the built environment:
" Good wind resource
" Strong support by City
" High electricity rates
" Availability of net metering and CA rebate
programs
" Prominently mentioned in DOE built-
environment wind turbine RD&D roadmap
! Effort should include:
" Develop detailed wind map for City
! CFD
! Anemometer measurements
! Wind tunnel
" Benchmark wind turbine test sites Danielle Murray
" Web-based data & info site
! Effort should involve:
" Government (SF, CEC, DOE, et al.)
" Industry
" Academia

13. DOE Built-Environment Wind Turbine RD&D Roadmap
! Purpose of roadmap to provide a framework for achieving vision
set forth by attendees of Built-Environment Wind Turbine
Workshop (Aug 2010, NWTC/NREL)
! Workshop vision statement:
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