Quantifying voyage optimisation with wind propulsion for short-term CO2 mitigation in shipping.
Description
Data availability description This study quantifies the interaction between wind propulsion and voyage optimisation to reduce carbon emissions in the global shipping sector. The repository contains the following folders: “Model code”, “Panamax ship performance files” and “Results and figure data”. First, the model uses the “create_batch_input_files.py” to split the simulations by month, route, ship type (wind-assist/reference) and simulation type (GCR/optimised), defines the constants for each batch of simulations and saves to a text file. Main.py then runs the sequential steps of the model as follows: 1. Load input variables from the batch text files (uses “my_constants.py”) 2. Loop across the month in the specified time steps 3. Load the u and v components of wind from the ECMWF ERA-Interim dataset and filter using GSHHS data (uses “wind_data_file_name.py”, “load_wind_data.py” and “filter_grid.py”) 4. Create the GCR grid and the three-dimensional spatial grid (if using) and calculate the wind speed and wind angle at each grid point (add the weather) (uses “gcr_calc.py”, “dp_grid_three_d.py”, “add_wind_data.py” and “wind_class.py”) 5. Calculate the fuel consumption of the reference ship with no sails at 12 knots and the fuel consumption of the wind-assisted ship on the out and return legs of EITHER a. the GCR or b. the optimised voyage for the input route and all arrival times. Also tracks the currents using NOAA current data (uses “route_calcs.py”, “dp_algorithm_three_d.py”, “ship_model_integration.py”, “land_avoidance.py”, “functions.py” and “load_current_data.py”) 6. Calculate the fuel savings of the wind-assisted ship relative to the reference ship at 12 knots on either the GCR or the optimised voyage 7. Save the data The Panamax ship performance files folder stores the data for the Panamax ship performance. Data is stored for ship speeds from 8 to 13 knots in intervals of 1 knot. Data is stored for both the wind-assisted ship with four Flettner rotors installed, and a reference ship with no Flettner rotors installed. A flag file is also included for each, which describes the speed state of the ship (whether the sails are providing full power and need to depower, or whether the ship can’t physically maintain the speed). The Results and figure data files contains the source data for the results, in Excel format.