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**Number range CHAPTERNATIONAL WIND TECHNOLOGY CENTER**

Initial Acquisition: 1993 \[280 acres\]

Secondary Acquisition: 2003 \[25 acres\]

Land Area: 305 acres

Nestled at the base of the Rocky Mountains just south of Boulder,
Colorado, is NREL\'s National Wind Technology Center (NWTC), the U.S.
Department of Energy\'s (DOE\'s) premier wind energy research and
development facility. At the NWTC, wind turbine developers work side by
side with NREL researchers to create advanced wind systems.
Manufacturers, wind plant operators, and utilities benefit from research
and technical support that is second to none.

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The NWTC meets a growing industry\'s critical research needs with its
indoor/outdoor state-of-the-art design and testing facilities. Wind
plant operators and electric utilities come here for technical
assistance as they integrate wind power plants into our nation\'s
electricity supply. Manufacturers come here for the world\'s leading
research and test support. Developing lightweight, reliable components
and testing complete systems are crucial for the emerging U.S. wind
industry. The National Wind Technology Center mission meets these
critical needs.

Sixteen test pads handle wind turbines ranging from one kilowatt to one
megawatt of power output. The test pads are fully instrumented so that
researchers can study every aspect of wind turbine performance,
including wind speed and direction, power output, torque, and other
critical factors. Data collected by sensors or video cameras are relayed
to a computer for real-time monitoring or storage. The turbines feed
power into the site\'s existing 13.2-kilovolt/480-volt power
distribution system.

**Building 251**

Building 251 is the hub of the National Wind Technology Center. In
addition to housing administrative and research support offices, the
facility\'s conference rooms enable NREL to host international wind
power specialists, conferences, and meetings. In the research support
offices, engineers develop state-of-the-art computer modeling software
to analyze data collected from tests and experiments as well as
next-generation turbine designs. Researchers in the support offices also
conduct design review and analysis, resource assessment, and utility
integration studies.

The high bay in Building 251 houses a 225-kW dynamometer with static and
dynamic load testing capabilities for small wind turbine components and
subsystems. The high bay also houses an environmental chamber capable of
exposing turbine components to extreme ambient temperatures such as
those found in Arctic environments or hot, humid climates.

**Dynamometer Test Facilities**

NREL\'s 7,500 square-foot dynamometer facility offers wind industry
engineers a unique opportunity to conduct lifetime endurance tests on a
wide range of wind turbine drivetrains and gearboxes at various speeds,
using low or high torque.

**Industrial User Facility**

NREL\'s Industrial User Facility (IUF) at the National Wind Technology
Center (NWTC) provides industry researchers with office space,
experimental laboratories, computer facilities for analytical work, and
space for assembling components and turbines used for atmospheric
testing. The facility also houses two blade stands equipped with
overhead cranes and servo-hydraulic systems, control rooms, a high bay,
and several smaller test bays that protect proprietary information while
companies disassemble turbines to analyze, test, and modify individual
components. In the high bay, NWTC researchers conduct a full range of
structural evaluations on turbine blades, including ultimate
static-strength, fatigue, vibration, and nondestructive tests. The IUF
and NREL\'s expertise help industry partners verify and improve new
blade designs, analyze blade structural properties, and improve their
manufacturing processes.

**Advanced Research Turbines**

The test facilities at the National Wind Technology Center (NWTC)
include two advanced research turbines, the Controls Advanced Research
Turbine (CART) and the CART3---a three-bladed version of the CART. The
CART tests new control schemes and equipment for reducing loads on wind
turbine components. As wind turbines become lighter and more flexible to
reduce costs, novel control mechanisms are necessary to stop high winds
from damaging the turbine. Since wind turbine designs must capture the
maximum amount of energy from the wind, engineers must devise new ways
of achieving this while controlling wind loads that would cause the
turbines to fatigue quickly. New control mechanisms and computer codes
can help the wind turbine shed some loads in extreme or very turbulent
winds. Both turbine configurations allow for the analysis of diverse
control schemes.

**Wind Turbine Test Pads**

In addition to the two advanced research turbines permanently installed
on the site, NREL provides test pads for manufacturers to test their
prototype machines. Companies that have had turbines tested at the
National Wind Technology Center include the Atlantic Orient Corporation,
Bergey Windpower, Southwest Wind Power, Northern Power Systems, the Wind
Turbine Company, and Global Energy Concepts (formerly Advanced Wind
Turbines).

**Site Issues and Challenges**

-   Wind fetch regime

-   NWEC vision

-   Infrastructure

    -   Water

    -   Sewer

    -   Power

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**Number range CHAPTERNWTC ADMINISTRATION BUILDING (BUILDING 251)**

Year Constructed: 1983

Initial Acquisition Cost: \$ 2,132,925

Replacement Plant Value: \$ 6,904,490

RPAM Condition: Excellent (\<2% RPV)

Space: 22,026 gsf

Net Usable Space: 19,830 nsf

Full Time Staff: 54

Building 251 is the hub of the National Wind Technology Center. In
addition to housing administrative and research support offices, the
facility contains a high bay testing area.

**Research Support**

In the research support offices, engineers develop state-of-the-art
computer modeling software to analyze next-generation turbine designs,
as well as the data collected from tests and experiments. Researchers
also conduct design review and analysis, resource assessment, and
utility integration studies. The facility\'s conference rooms enable
NREL to host international wind power specialists, conferences, and
meetings.

The high bay in Building 251 houses a 225-kW dynamometer for testing
small wind turbine components and subsystems. The high bay is also used
for static and dynamic load testing of small wind turbine blades, as
well as testing of blade components. As part of the component testing,
the high bay also houses an environmental chamber. This chamber exposes
turbine components to extreme ambient temperatures like those found in
Arctic environments or hot, humid climates.

> **Small Turbine Testing**
>
> NREL\'s 225-kW dynamometer, located in the NWTC\'s Building 251 high
> bay, is suitable for testing wind turbine components from the smallest
> turbines up to those rated at nearly 200 kW. Typical turbine
> components include subsystems, generators, gearboxes, mechanical or
> electro-dynamic brakes, power electronics, control systems, and
> software. The facility is capable of 225-kW peak power and shaft
> speeds up to 4,140 rpm.
>
> **Computer Modeling**
>
> To predict accurately the behavior of new design concepts, NREL has
> developed many software tools that produce realistic models that
> simulate the behavior of a wind turbine in complex environments --
> storm winds, waves offshore, earthquake loading, and extreme
> turbulence -- and model the effects of turbulent inflow, unsteady
> aerodynamic forces, structural dynamics, drive train response, and
> control systems. NREL has also developed preprocessors to help build
> the models, postprocessors to analyze the results, and utilities to
> run and manage the processing tasks.
>
> In 2005, NREL researchers worked with Germanischer Lloyd of Hamburg,
> Germany to approve two of NREL\'s wind turbine design codes for
> calculating land-based wind turbine loads for design and
> certification. Although many U.S. wind turbine manufacturers have
> relied on these design codes to estimate the design loads of their
> turbines in the past, until recently, the codes were not accepted by
> certifying agencies in Europe.

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> **Design Review and Analysis**
>
> NREL researchers provide industry partners with design reviews and
> analyses, technical assistance, and parallel research. Design review
> and analysis ensures that products resulting from advances in R&D are
> developed in a logical and safe manner and in compliance with the
> applicable international certification standards. It also helps reduce
> the risks of development and ensure market acceptance for both
> utility-scale and distributed wind energy technologies.
>
> In addition to design review, NREL may also offer technical assistance
> to solve specific technical problems and conduct parallel research to
> provide a foundation for increasingly complex engineering reviews and
> analyses to meet the needs of highly advanced turbine configurations.

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> **Wind Resource Assessment**
>
> All markets for wind turbines require an estimate of how much wind
> energy is available at potential development sites. Correct estimation
> of the energy available in the wind can make or break the economics of
> wind farm development. Wind maps developed in the late \'70s and early
> \'80s provided reasonable estimates of areas in which good wind
> resources could be found. But new tools and new data available from
> satellites and new sensing devices now allow researchers to create
> even more accurate and detailed wind maps of the world.
>
> Wind mapping techniques developed by NREL and U.S. companies are being
> used to produce high-resolution projections of U.S. and foreign
> regions that are painting a completely new picture of wind potential.
> These maps are created using highly accurate GPS mapping tools and a
> vast array of satellite, weather balloon, and meteorological tower
> data, combined with much-improved numerical computer models. The
> higher horizontal resolution of these maps (1 km or finer) allows for
> more accurate siting of wind turbines and has led to the recognition
> of higher-class winds in areas where none were thought to exist.
>
> The ability to predict accurately when the wind will blow will help
> remove barriers to wind energy development by allowing
> wind-power-generating facilities to commit to power purchases in
> advance. NREL researchers work with federal, state, and private
> organizations to validate the nation\'s wind resources and support
> advances in wind forecasting techniques and dissemination. Wind
> resource validation is important for both wind resource assessment and
> the integration of wind farms into an energy grid. Validating new,
> high-resolution wind resource maps will provide an accurate reading of
> the wind resource at a particular site. Development of short-term (1
> to 4 hours) forecasting tools will help energy producers proceed with
> new wind farm projects and avoid the penalties they must pay if they
> do not meet their hourly generation targets. In addition, validating
> new high-resolution wind resource maps will give people interested in
> developing wind energy projects greater confidence as to the level of
> wind resource for a particular site.

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> **Utility Integration Assessment**
>
> The integration of wind energy into the electric generation
> industry\'s supply mix is one of the issues industry grapples with.
> The natural variability of the wind resource raises concerns about how
> wind can be integrated into routine grid operations, particularly with
> regard to the effects of wind on regulation, load following,
> scheduling, line voltage, and reserves.
>
> At NREL, researchers work with wind developers and electricity
> suppliers, using a range of methods, tools, and analyses to further
> the understanding of the economic and operational effects of wind
> generation on the electric supply system. Their strategy is to define
> and complete activities, on a region-by-region basis, that provide
> system operators, planners, and relevant decision makers with the
> information and tools needed for equitable treatment of wind power in
> the energy marketplace.

**Site Issues and Challenges**

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**Number range CHAPTERDYNAMOMETER TEST FACILITY**

Year Constructed: 1999

Initial Acquisition Cost: \$2,233,717

Replacement Plant Value: \$2,233,717

RPAM Condition:

Space: gsf

Net Usable Space: nsf

Full Time Staff: 0

NREL\'s 7,500-square-foot dynamometer facility offers wind industry
engineers a unique opportunity to conduct lifetime endurance tests on a
wide range of wind turbine drivetrains and gearboxes at various speeds,
using low or high torque. It includes a powerful 3,350-hp electric motor
coupled to a 2.5 megawatt (MW), three-stage epicyclic gearbox that can
produce variable speeds from 0 to 146 revolutions per minute (rpm) and
run at torque levels up to 9.6 million inch-pounds to simulate the
effects of various wind conditions. Its flexible design allows it to
couple with the shaft position of any wind turbine system from 100
kilowatts (kW) to two (2) MW in size. A 50-ton electric bridge crane
operates 30 feet (9.1 meters) above the test table to move the large
drivetrains into test position.

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NREL\'s 2.5-MW dynamometer facility was developed to help wind energy
researchers recreate, in a laboratory environment, extreme wind
conditions on wind turbine drivetrains.

A few months of endurance testing on NREL\'s 2.5-MW dynamometer can
provide engineers with an equivalent of 30 years of use and a lifetime
of braking cycles to help them determine which components are
susceptible to wear. Because these endurance tests require several
months of continuous unattended operation, the dynamometer test facility
includes a sophisticated Supervisory Control and Data Acquisition
(SCADA) system that monitors the critical test parameters and can stop
the test if abnormal conditions are detected.

**Facility Issues and Challenges**

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**Number range CHAPTERINDUSTRIAL USER FACILITY (IUF)**

Year Constructed: 1996

Initial Acquisition Cost: \$2,061,198

Replacement Plant Value: \$3,678,570

RPAM Condition: Good (2-\<5% RPV)

Space: 11,394 gsf

Net Usable Space: 10,796 nsf

Full Time Staff: 11

NREL\'s Industrial User Facility (IUF) at the National Wind Technology
Center (NWTC) provides office space for industry researchers,
experimental laboratories, computer facilities for analytical work, and
space for assembling components and turbines for atmospheric testing.
The facility also houses two blade stands equipped with overhead cranes
and servo-hydraulic systems, control rooms, a high bay, and several
smaller test bays that protect proprietary information while companies
disassemble turbines to analyze, test, and modify individual components.

**Turbine Blade Testing**

In the high bay, NWTC researchers conduct a full range of structural
evaluations on turbine blades, including ultimate static-strength,
fatigue, vibration, and nondestructive tests. The IUF and NREL\'s
expertise help industry partners verify and improve new blade designs,
analyze blade structural properties, and improve their manufacturing
processes.

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wind turbines grow in size and their blades become longer and more
flexible, it becomes more difficult to test the blades for endurance. At
the same time, test methods developed for smaller blades have become
more expensive and less effective. To test the new, larger blades, NREL
installed a larger blade test stand capable of testing blades up to 50 m
in length.

**Hydraulic Resonance Blade Test System**

NREL also recently developed a novel hydraulic resonance blade test
system. The new test system uses one-third as much energy as the
previous system, and the blade oscillates at more than twice the
conventional rate. It now takes less than 2 months (the previous system
test took up to 4 months) to apply 3 million cycles to fatigue test a
blade. The new system, which will test blades manufactured for giant
multi-megawatt turbines, is the only one of its kind in the world.

**Facility Issues and Challenges**

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**HYBRID POWER TEST BED FACILITY**

Year Constructed: 1996

Initial Acquisition Cost: \$276,693

Replacement Plant Value: \$561,111

RPAM Condition: Excellent (\<2% RPV)

Space: 1,790 gsf

Net Usable Space: 1,647 nsf

Full Time Staff: 1

The Hybrid Power Test Bed Facility is a unique facility that uses
electricity from wind turbines to produce and store pure hydrogen,
offering what may become an important new template for future energy
production.

The facility links two wind turbines to electrolyzers, which pass the
wind-generated electricity through water to split the liquid into
hydrogen and oxygen. The hydrogen can be stored and used later to
generate electricity either from an internal combustion engine turning a
generator or from a fuel cell. In either case, there are no harmful
emissions and the only by-product from using the hydrogen fuel is water.

Located at NREL\'s National Wind Technology Center near Boulder, Colo.,
the facility houses the electrolyzers and a device to compress the
hydrogen for storage; four large, high-tech tanks to store the hydrogen;
a generator run by an engine that burns hydrogen; and a control room
building, where computers monitor all the steps of the process.

Currently, there are limitations to both wind power and hydrogen. Wind
farms only generate electricity when the wind is blowing, which is about
one-third of the time in the United States. This creates the need for
backup generation, which is usually fossil-fueled.  Hydrogen, while the
most common element in the universe, isn\'t found in its pure form on
Earth and must be either electrolyzed from water or stripped out of
natural gas, which are energy-intensive processes that result in
greenhouse gas emissions.

**Facility Issues and Challenges**

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**DISTRIBUTED ENERGY RESOURCES TEST FACILITY**

Year Constructed: 1999

Initial Acquisition Cost: \$253,445

Replacement Plant Value: \$1,755,432

RPAM Condition: Excellent (\<2% RPV)

Space: 2,212 gsf

Net Usable Space: 1,990 nsf

Full Time Staff: 0

NREL\'s Distributed Energy Resources Test Facility is a working
laboratory for interconnection and systems integration testing. This
state-of-the-art facility includes generation, storage, and
interconnection technologies as well as electric power system equipment
capable of simulating a real-world electric system.

Researchers at the facility can vary equipment configurations and
introduce common electrical disturbances such as sags, swells, and
harmonic issues on the replica grid. These capabilities allow them to
evaluate the real-time dynamics of distributed power systems, collect
information about the long-term performance of such systems, and test
new design concepts.

**Equipment Characterization**

Data from tests at the facility are used to characterize Distributed
Energy Resources (DER) equipment and support the development and
validation of interconnection standards and certification tests. These
results can lead to better equipment, improvements in meeting
interconnection requirements, and a better understanding of the dynamics
of equipment interconnected with the power grid. Additionally, industry
and academia use the facility for cooperative testing and
characterization of developmental distributed energy systems.

**Renewable Energy Sources and Hydrogen Production**

NREL\'s DER Test Facility is also the ideal location for examining the
issues related to renewable energy sources and hydrogen production via
the electrolysis of water. The facility offers the flexibility of
interconnecting various renewable sources to electrolyzers and their
hydrogen-producing stacks. NREL is testing integrated electrolysis
systems and investigating options for improved designs that will lower
capital costs and enhance performance of the naturally varying power
input from renewable sources to the electrolyzer.

**Facility Issues and Challenges**

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**NWTC BLADE TEST FACILITY (BUILDING 252)**

Year Constructed: 1979

Initial Acquisition Cost: \$40,000

Replacement Plant Value: \$803,424

RPAM Condition: Good (2-\<5% RPV)

Space: 2,468 gsf

Net Usable Space: 2,221 nsf

Full Time Staff: 0

This facility is a small open bay laboratory with a control room for
testing small turbine blades. Both destructive and non-destructive
testing occurs in this facility. Sometimes the ultimate strength of the
blade is tested by bending it until it breaks. Sophisticated computer
models help researchers analyze the results of these tests and improve
future designs.

**Facility Issues and Challenges**