**Progress Update - Western Wind and Solar Integration Study**

6/26/08

**Wind mesoscale modeling**

3TIER completed development of time-series wind speed and power data for
the Western US. The wind speed dataset includes wind speeds at 5 hub
heights for 10 minute intervals for 2004-2006 at a 2 km resolution.
These 1.2 million sites were down-selected to 32,000 sites for wind
power profile development, based on specific criteria (transmission
access, load correlation, resource quality). Public webinars were held
in March to receive feedback on sites selected and to request modeling
of additional sites. Ten Vestas V90 3 MW turbines at 100m hub height
(totaling 30 MW) were modeled on each 2km x 2km site (for a total of 960
GW) using 3TIER's SCORE methodology. In addition, 3TIER has modeled
day-ahead wind power forecasts for each hour. 3TIER has completed a
user-friendly web interface that will be made public this summer so that
wind power profiles for specific sites will be publicly available for
research, studies, and prospecting. 3TIER has completed validation
reports that compare the mesodata to measured data and NREL and others
are reviewing accuracy prior to public release of data.

**Solar mesoscale modeling and preliminary site selection**

NREL has received solar direct normal and global insolation data at 10km
resolution and at hourly intervals for 2004-6 from Richard Perez of
SUNY. 3TIER has generated solar forecasts as part of their mesomodel.
NREL has developed over 200 GW of power profiles for concentrating solar
power (CSP) plants based on parabolic trough technology with 6 hours of
thermal storage. NREL has also modeled distributed PV profiles for 150
sites.

**Scenarios**

Based on the output of the August Stakeholder Meeting, GE will run
production simulations on the selected scenarios in the latter half of
2008. The high renewables basecase for 2017 is detailed in the table
below. Plant capacities are approximate and depend on the actual
capacity factor of each individual site.

  -------------------- --------------- ----------- ----------- ------------
                       Wind            Solar PV    CSP         Total

  Study footprint      30% by energy   1.5%        3.5%        35%
  (WestConnect)                                                

                       28,256 MW       2472 MW     2884 MW     33,613 MW

                                                               

  Rest of WECC         20%             0.9%        2.1%        23%

                       36,767 MW       2895 MW     3378 MW     43,040 MW

                                                               

  Total                65,023 MW       5368 MW     6262 MW     76,654 MW
  -------------------- --------------- ----------- ----------- ------------

**Site selection**

GE is undertaking a detailed site selection process to down-select from
the 960GW of wind and 200 GW of CSP profiles to the needed capacities
according to the above table. They are developing two "bookend"
scenarios, based on 1) each transmission area using in-area renewables,
and 2) development of the best quality resources available in the
WestConnect footprint. They will also develop a more realistic scenario,
in which the transmission costs trade off with lowered wind energy
costs.

**Statistical Analysis**

GE is undertaking statistical analysis of a 2008 baseline scenario and
the first "bookend" scenario described above. They will present results
on this analysis at the August Stakeholder Meeting. Based on this
analysis, other scenarios will be developed and proposed. These may
include a "load correlation" scenario and a high solar scenario.

The study year is 2017, to line up with WECC transmission planning.
Loads, utility plant portfolios, and planned transmission will all be
projected out to 2017. We will model 2017 three times, using historical
weather (solar, wind) and load data from 2004, 2005, and 2006, to get a
sense of interannual variability.

**Stakeholder Meeting**

The next Stakeholder Meeting (open to all) is August 14 and will be held
at a hotel near the Denver International Airport. This will include
statistical analysis results of the first bookend scenario and the
baseline scenario as well as a description of proposed scenarios for the
production simulation analysis. We expect preliminary production
simulation analysis results at the end of 2008.

Information about the study can be found at

<http://westconnect.com/>

Please feel free to contact me if you have any questions or further
input.

Debbie Lew

National Wind Technology Center

National Renewable Energy Laboratory

1617 Cole Blvd

Golden, CO 80401

work: 303-384-7037

email: debra_lew@nrel.gov