NRWAL documentation

What is NRWAL?

The National Renewable Energy Laboratory Wind Analysis Library (NRWAL):

1. A library of offshore wind cost equations (plus new energy technologies like marine hydro!)

2. Easy equation manipulation without editing source code

3. Full continental-scale integration with the NREL Renewable Energy Potential Model (reV)

4. Ready-to-use configs for basic users

5. Dynamic python tools for intuitive equation handling

6. One seriously badass sea unicorn

To get started with NRWAL, check out the NRWAL Config documentation or the NRWAL example notebook. You can also launch the notebook in an interactive jupyter shell right in your browser without any downloads or software using binder.

Ready to build a model with NRWAL but don’t want to contribute to the library? No problem! Check out the example getting started project here.

Here is the important stuff:

• The NRWAL Equation Library.

• Default NRWAL Configs.

Installing NRWAL

Option 1: Install from PIP or Conda (recommended for analysts):

1. Create a new environment:

   conda create --name nrwal

2. Activate directory:

   conda activate nrwal

3. Install reVX:

   1. pip install NREL-NRWAL or

   2. conda install nrel-nrwal --channel=nrel

Option 2: Clone repo (recommended for developers)

1. from home dir, git clone https://github.com/NREL/NRWAL.git

   1. enter github username

   2. enter github password

2. Create NRWAL environment and install package

   1. Create a conda env: conda create -n nrwal

   2. Run the command: conda activate nrwal

   3. cd into the repo cloned in 1.

   4. prior to running pip below, make sure the branch is correct (install from master!)

   5. Install NRWAL and its dependencies by running: pip install . (or pip install -e . if running a dev branch or working on the source code)

NRWAL Variables for Offshore Wind (OSW)

NRWAL Inputs

Variable Name	Long Name	Source	Units
aeff	Array Efficiency	array_efficiency input layer, computed from ORBIT	%
capex_multi	CAPEX Multiplier	Supplied by user	unit-less
depth	Water depth (positive values)	bathymetry input layer	m
dist_a_to_s	Distance from assembly area to site	Computed from assembly_area input layer	km
dist_op_to_s	Distance from operating port to site	ports_operations input layer	km
dist_p_to_a	Distance from port (construction no-limit) to assembly area	assembly_area input layer	km
dist_p_to_s	Distance from construction port to site	ports_construction input layer	km
dist_p_to_s_nolimit	Distance from no-limit construction port to site	ports_construction_nolimit input layer	km
dist_s_to_l	Distance site to nearest land	dist_to_coast input layer	km
fixed_downtime	Average weather downtime for fixed structure turbines	weather_downtime_fixed_bottom input layer	fraction
floating_downtime	Average weather downtime for floating structure turbines	weather_downtime_floating input layer	fraction
gcf	Gross capacity factor	Computed by reV / SAM with losses == 0	unit-less
hs_average	Significant wave height to determine weather downtime	weather_downtime_mean_wave_height_buoy input layer	m
num_turbines	Number of turbines in array	Supplied by user	unit-less
transmission_multi	Tranmission cost multiplier	Supplied by user	unit-less
turbine_capacity	Capacity of each turbine in the array	Supplied by user	MW

Recommended Citation

If using the NRWAL software (replace with current version and DOI):

• Grant Buster, Jake Nunemaker, and Michael Rossol. The National Renewable Energy Laboratory Wind Analysis Library (NRWAL). https://github.com/NREL/NRWAL (version v0.0.2), 2021. https://doi.org/10.5281/zenodo.4705961.

If using the Offshore Wind (OSW) cost equations:

• Beiter, Philipp, Walter Musial, Aaron Smith, Levi Kilcher, Rick Damiani, Michael Maness, Senu Sirnivas, Tyler Stehly, Vahan Gevorgian, Meghan Mooney, and George Scott. “A Spatial-Economic Cost-Reduction Pathway Analysis for U.S. Offshore Wind Energy Development from 2015–2030.” National Renewable Energy Lab. (NREL), Golden, CO (United States), September 1, 2016. https://doi.org/10.2172/1324526. https://www.nrel.gov/docs/fy16osti/66579.pdf.

If using the marine energy reference model (RM) cost models:

• https://energy.sandia.gov/programs/renewable-energy/water-power/projects/reference-model-project-rmp/

• Jenne, D. S., Y. H. Yu, and V. Neary. “Levelized Cost of Energy Analysis of Marine and Hydrokinetic Reference Models: Preprint.” National Renewable Energy Lab. (NREL), Golden, CO (United States), April 24, 2015. https://www.osti.gov/biblio/1215196-levelized-cost-energy-analysis-marine-hydrokinetic-reference-models-preprint.