New feature: Custom Semisubmersible design

ORBIT/core/defaults/common_costs.yaml

@@ -66,6 +66,8 @@ semisubmersible_design:
   truss_CR: 6250                                # USD/t
   heave_plate_CR: 6250                          # USD/t
   secondary_steel_CR: 7250                      # USD/t
+  steel_CR: 4500                                # USD/t *CustomSemiSub*
+  ballast_material_CR: 150
 
 # Mooring system component cost rates
 mooring_system_design:                          # USD/m

ORBIT/manager.py

@@ -40,6 +40,7 @@
     SemiSubmersibleDesign,
     CustomArraySystemDesign,
     OffshoreSubstationDesign,
+    CustomSemiSubmersibleDesign,
     SemiTautMooringSystemDesign,
     OffshoreFloatingSubstationDesign,
 )
@@ -80,6 +81,7 @@ class ProjectManager:
         MooringSystemDesign,
         SemiTautMooringSystemDesign,
         SemiSubmersibleDesign,
+        CustomSemiSubmersibleDesign,
         SparDesign,
         ElectricalDesign,
     )

ORBIT/phases/design/__init__.py

@@ -16,5 +16,8 @@
 from .export_system_design import ExportSystemDesign
 from .mooring_system_design import MooringSystemDesign
 from .scour_protection_design import ScourProtectionDesign
-from .semi_submersible_design import SemiSubmersibleDesign
+from .semi_submersible_design import (
+    SemiSubmersibleDesign,
+    CustomSemiSubmersibleDesign,
+)
 from .SemiTaut_mooring_system_design import SemiTautMooringSystemDesign

ORBIT/phases/design/semi_submersible_design.py

@@ -5,6 +5,8 @@
 __maintainer__ = "Jake Nunemaker"
 __email__ = "[email protected]"
 
+import numpy as np
+
 from ORBIT.phases.design import DesignPhase
 
 """
@@ -220,3 +222,272 @@ def detailed_output(self):
         }
 
         return _outputs
+
+
+"""Provides the `CustomSemiSubmersibleDesign` class."""
+
+__author__ = "Matt Shields"
+__copyright__ = "Copyright 2020, National Renewable Energy Laboratory"
+__maintainer__ = "Nick Riccobono"
+__email__ = "[email protected]"
+
+"""
+Based on semisub design from 15 MW RWT
+
+[1]	C. Allen et al., “Definition of the UMaine VolturnUS-S Reference Platform
+ Developed for the IEA Wind 15-Megawatt Offshore Reference Wind Turbine,”
+ NREL/TP--5000-76773, 1660012, MainId:9434, Jul. 2020. doi: 10.2172/1660012.
+[2]	K. L. Roach, M. A. Lackner, and J. F. Manwell, “A New Methodology for
+ Upscaling Semi-submersible Platforms for Floating Offshore Wind Turbines,”
+ Wind Energy Science Discussions, pp. 1–33, Feb. 2023,
+ doi: 10.5194/wes-2023-18.
+"""
+
+
+class CustomSemiSubmersibleDesign(DesignPhase):
+    """Customized Semi-Submersible Substructure Design."""
+
+    expected_config = {
+        "site": {"depth": "m"},
+        "plant": {"num_turbines": "int"},
+        "turbine": {"turbine_rating": "MW"},
+        "semisubmersible_design": {
+            "towing_speed": "km/h (optional, default: 6)",
+            "column_diameter": "m (optional, default: 12.5)",
+            "wall_thickness": "m (optional, default: 0.045)",
+            "column_height": "m (optional, default: 35)",
+            "pontoon_length": "m (optional, default: 51.75)",
+            "pontoon_width": "m (optional, default: 12.5)",
+            "pontoon_height": "m (optional, default: 7)",
+            "strut_diameter": "m (optional, 0.9)",
+            "steel_density": "kg/m^3 (optional, default: 7980)",
+            "ballast_mass": "tonnes (optional, default 2540)",
+            "tower_interface_mass": "tonnes (optional, default 100)",
+            "steel_CR": "$/tonne (optional, default: 4500)",
+            "ballast_material_CR": "$/tonne (optional, default: 150)",
+        },
+    }
+
+    output_config = {
+        "substructure": {
+            "mass": "t",
+            "unit_cost": "USD",
+            "towing_speed": "km/h",
+        }
+    }
+
+    def __init__(self, config, **kwargs):
+        """
+        Creates an instance of `CustomSemiSubmersibleDesign`.
+
+        Parameters
+        ----------
+        config : dict
+        """
+
+        config = self.initialize_library(config, **kwargs)
+        self.config = self.validate_config(config)
+        self._design = self.config.get("semisubmersible_design", {})
+
+        self.num_columns = kwargs.get("number_columns", 3)
+
+        self._outputs = {}
+
+    def run(self):
+        """Main run function."""
+
+        self.calc_geometric_scale_factor()
+
+        substructure = {
+            "mass": self.substructure_mass,
+            "unit_cost": self.substructure_unit_cost,
+            "towing_speed": self._design.get("towing_speed", 6),
+        }
+
+        self._outputs["substructure"] = substructure
+
+    def calc_geometric_scale_factor(self, **kwargs):
+        """Calculates the geometric factor to scale the size of the semi-
+        submersible. Upscaling methodology and parameters used are found on
+        Lines 335-340 [2].
+        """
+
+        turbine_diameter = self.config["turbine"].get("rotor_diameter")
+
+        if turbine_diameter is None:
+            raise KeyError("Turbine rotor diameter not specified.")
+
+        # IEA-15MW 120m radius
+        ref_radius = kwargs.get("ref_radius", 120.0)
+
+        # power-law parameter
+        alpha = kwargs.get("alpha", 0.72)
+
+        self.geom_scale_factor = (
+            float(turbine_diameter) / 2 / ref_radius
+        ) ** alpha
+
+    @property
+    def bouyant_column_volume(self):
+        """
+        Returns the volume of a capped, hollow, cylindrical column,
+        assuming the wall-thickness remains constant [2].
+        """
+
+        dc = self._design.get("column_diameter", 12.5) * self.geom_scale_factor
+        hc = self._design.get("column_height", 35) * self.geom_scale_factor
+        tc = self._design.get("wall_thickness", 0.045)
+
+        return (np.pi / 4) * (hc * dc**2 - (hc - 2 * tc) * (dc - 2 * tc) ** 2)
+
+    @property
+    def center_column_volume(self):
+        """
+        Returns the volume of a hollow cylindrical column between turbine and
+        pontoons, assuming wall-thickness remains constant [2].
+        """
+
+        dc = 10.0  # fixed tower diameter
+        hc = self._design.get("column_height", 35) * self.geom_scale_factor
+        hp = self._design.get("pontoon_height", 7) * self.geom_scale_factor
+        tc = self._design.get("wall_thickness", 0.045)
+
+        return (np.pi / 4) * (
+            (hc - hp) * dc**2 - (hc - hp) * (dc - 2 * tc) ** 2
+        )
+
+    @property
+    def pontoon_volume(self):
+        """
+        Returns the volume of a single hollow rectangular pontoon that connects
+        the central column to the outer columns, assuming wall-thickness
+        reamins constant [2].
+        """
+        # TODO: Subtract semi-circular area from fairlead column?
+
+        lp = self._design.get("pontoon_length", 51.75) * self.geom_scale_factor
+        wp = self._design.get("pontoon_width", 12.5) * self.geom_scale_factor
+        hp = self._design.get("pontoon_height", 7) * self.geom_scale_factor
+        tp = self._design.get("wall_thickness", 0.045)
+
+        return (hp * wp - (hp - 2 * tp) * (wp - 2 * tp)) * lp
+
+    @property
+    def strut_volume(self):
+        """
+        Returns the volume of a single solid strut that connects
+        the central column to the outer columns.
+        """
+
+        lp = self._design.get("pontoon_length", 51.75) * self.geom_scale_factor
+        ds = self._design.get("strut_diameter", 0.9) * self.geom_scale_factor
+
+        return (np.pi / 4) * (ds**2) * lp
+
+    @property
+    def substructure_steel_mass(self):
+        """Returns the total mass of structural steel in the substructure."""
+
+        # TODO: Separate out different steels for each component
+
+        density = self._design.get("steel_density", 7980)
+
+        return (density / 1000) * (
+            self.num_columns * self.bouyant_column_volume
+            + self.center_column_volume
+            + self.num_columns * self.pontoon_volume
+            + self.num_columns * self.strut_volume
+        )
+
+    @property
+    def ballast_mass(self):
+        """Returns the mass of fixed ballast. Default value from [1]."""
+        # TODO: Scale ballast mass with some factor?
+        # Fixed/Fluid needs to be addressed because 11,300t of seawater is used
+        # to submerge the platform.
+
+        return self._design.get("ballast_mass", 2540)
+
+    @property
+    def tower_interface_mass(self):
+        """Returns the mass of tower interface. Default value from [1]."""
+
+        # TODO: Find a model to estimate the mass for a tower interface
+
+        return self._design.get("tower_interface_mass", 100)
+
+    @property
+    def substructure_steel_cost(self):
+        """Returns the total cost of structural steel of the substructure
+        in $USD.
+        """
+
+        _key = "steel_CR"
+        self.steel_cr = self._design.get(
+            _key, self.get_default_cost("semisubmersible_design", _key)
+        )
+        return self.steel_cr * self.substructure_steel_mass
+
+    @property
+    def substructure_mass(self):
+        """
+        Returns the total mass of structural steel and iron ore ballast
+        in the substructure.
+        """
+
+        return sum(
+            [
+                self.substructure_steel_mass,
+                self.ballast_mass,
+                self.tower_interface_mass,
+            ]
+        )
+
+    @property
+    def substructure_unit_cost(self):
+        """
+        Returns the total material cost of a single substructure.
+        Does not include final assembly or transportation costs.
+        """
+
+        _key = "ballast_material_CR"
+        ballast_cr = self._design.get(
+            _key, self.get_default_cost("semisubmersible_design", _key)
+        )
+
+        return (
+            self.substructure_steel_cost
+            + ballast_cr * self.ballast_mass
+            + self.steel_cr * self.tower_interface_mass
+        )
+
+    @property
+    def design_result(self):
+        """Returns the result of `self.run()`."""
+
+        if not self._outputs:
+            raise Exception("Has `CustomSemiSubmersibleDesign` been ran yet?")
+
+        return self._outputs
+
+    @property
+    def total_cost(self):
+        """Returns total phase cost in $USD."""
+
+        num = self.config["plant"]["num_turbines"]
+        return num * self.substructure_unit_cost
+
+    @property
+    def detailed_output(self):
+        """Returns detailed phase information."""
+
+        _outputs = {
+            "substructure_steel_mass": self.substructure_steel_mass,
+            "substructure_steel_cost": self.substructure_steel_cost,
+            "substructure_mass": self.substructure_mass,
+            "substructure_cost": self.substructure_unit_cost,
+            "ballast_mass": self.ballast_mass,
+            "tower_interface_mass": self.tower_interface_mass,
+        }
+
+        return _outputs

docs/source/changelog.rst

@@ -5,6 +5,18 @@ ORBIT Changelog
 
 Unreleased (TBD)
 ----------------
+Custom Semi-Submersible Design
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+- The ``CustomSemiSubmersibleDesign`` class was added to semi_submersible_design.py.
+- Based on VolturnUS-S by U-Maine. `https://www.nrel.gov/docs/fy20osti/76773.pdf`
+- All design defaults are set to be consistent with 15MW IEA turbine
+- Scaling logic added based on U-Mass paper. `https://wes.copernicus.org/preprints/wes-2023-18/wes-2023-18.pdf`
+- Added tests to confirm that volumns and masses are calculated appropriately
+- Added Example - Custom Semisubmersible notebook and yaml config file.
+- Updated docs with citations.
+
+Relocate-get-costs
+~~~~~~~~~~~~~~~~~~
 - Relocated all the get design costs in each design class to `common_cost.yaml`. Spar, Semisub, monopile, electrical, offshore substation, and mooring designs all recieved this update.
 
 Merged SemiTaut Moorings

docs/source/phases/design/doc_SemiSubmersibleDesign.rst

@@ -11,8 +11,36 @@ The semi-submersible design module in ORBIT is based on previous modeling
 efforts undertaken by NREL, [#maness2017]_. The technical documentation for
 this tool can be found `here <https://www.nrel.gov/docs/fy17osti/66874.pdf>_`.
 
+Custom Semi-Submersible Design Methodology
+==========================================
+For details of the code implementation, please see
+:doc:`Semi-Submersible Design API <api_SemiSubmersibleDesign>`.
+
+(Custom) Overview
+-----------------
+
+This new addition to ORBIT's semi-submersible design capabilities by letting
+the user specify all the dimensions of the platform. IEAt was designed based on
+the IEA-15MW reference turbine and the VolturnUS-S Reference Platform developed
+by the University of Maine.[#allen2020]_.The triangular base uses three steel
+columns equipped with ballast material. Each column is connected to a
+central-column, where the turbine is afixed, by pontoons and spars.
+Additionally, this new model uses the methodology proposed in [#roach2023]_ to
+scale the platform to other turbine sizes.
+
 References
 ----------
 
 .. [#maness2017] Michael Maness, Benjamin Maples, Aaron Smith,
-    NREL Offshore Balance-of-System Model, 2017
+    NREL Offshore Balance-of-System Model, 2017.
+    `https://www.nrel.gov/docs/fy17osti/66874.pdf`
+
+.. [#allen2020] Christopher Allen, Anthony Viselli, Habib Dagher,
+    Andrew Goupee, Evan Gaertner, Nikhar Abbas, Matthew Hall,
+    and Garrett Barter. Definition of the UMaine VolturnUS-S Reference Platform
+    Developed for the IEA Wind 15-Megawatt Offshore Reference Wind Turbine.
+    `https://www.nrel.gov/docs/fy20osti/76773.pdf`
+
+.. [#roach2023] Kaylie Roach, Matthew Lackner, James Manwell. A New Method for
+    Upscaling Semi-submersible Platforms for Floating Offshore Wind Turbines.
+    `https://wes.copernicus.org/preprints/wes-2023-18/wes-2023-18.pdf`