transport-carbon 0.0.5

Introduction

This library provides an open source Python package for calculating the carbon footprint of transport (UK-focused to begin with). The final version will include transport by land, sea or air, whether freight or business travel, by any mode covered in the Defra GHG Emissions Factors for Company Reporting.

It is currently in pre-alpha stage as several of the distance functions are incomplete (see Contributing and To-do List section).

distance: provide the distance between two locations using a given transport mode These functions are provided from a range of sources at present, some of which need more work, and some of which need replacing.

All distance functions are in the format distance.[mode]_distance(origin, destination, units), and the units default to “km”.

>>> from transport_carbon import *
>>> road_distance('London', 'Leeds')
313.473

The available functions are:

air_distance(origin, destination[, units])

This function is complete. It calculates the great circle distance between two points. The emissions factors already include an uplift to account for non-optimal routing and stacking at airports.

rail_distance(origin, destination[, units])

This function has a working prototype. It is quite successful when used on journeys that are on a single train line (as they should be), however in trying to calculate more complicated journeys it often fails to find a route.

road_distance(origin, destination[, mode[, units])

This function is complete. It is based on the Google Directions API as implemented in the g_directions module. mode defaults to “driving” and units defaults to “km”.

sea_distance(origin, destination[, units])

carbon: provide the GHG emissions associated with a form of freight pr business transport The GHG emissions factors are based on the data provided by Defra in their [2013 Government GHG Conversion Factors for Company Reporting](http://www.ukconversionfactorscarbonsmart.co.uk/) now provided in a web service from Ricardo-AEA.

For all functions, ghg_units defaults to “kgCO2e”. Well to tank (upstream) emissions are available using “kgCO2eWTT”. Other emissions factors available are “kgCO2”, “kgCH4” and “kgN2O”.

>>> from transport_carbon import *
>>> motorbike_ghg(size="Small")
0.11890999999999999

Business travel

air_ghg([origin[, destination[, ghg_units[, haul[, travel_class[, radiative_forcing]]]]]]

Requires either origin and destination, or haul to be passed. If unspecified radiative_forcing defaults to True.

bus_ghg([ghg_units[, bus_type]])

If unspecified, bus_type defaults to “AverageLocalBus”.

car_ghg([ghg_units[, select_by[, size[, market_segment[, fuel[, unit]]]]]])

If unspecified, select_by defaults to “Size”, size defaults to “Average”, market_segment defaults to “UpperMedium”, fuel defaults to “Unknown”, and unit defaults to “km”.

motorbike_ghg([ghg_units[, size])

If unspecified, size defaults to “Average”.

rail_ghg([ghg_units[, ghg_units[, rail_type]])

If unspecified, rail_type defaults to “NationalRail”.

ferry_ghg([ghg_units[, passenger_type]])

If unspecified, passenger_type defaults to “Average”.

taxi_ghg([ghg_units[, taxi_type[, unit]]])

If unspecified, taxi_type defaults to “RegularTaxi”, and units defaults to “PassengerKm”.

Freight transport

air_freight_ghg()([origin[, destination[, ghg_units[, haul[, radiative_forcing]]]]]]

Requires either origin and destination, or haul to be passed. ghg_units defaults to kgCO2e and radiative_forcing defaults to True.

cargo_ship_ghg([ghg_units[, ship_type[, capacity[, capacity_unit]]]])

If unspecified, ship_type defaults to “BulkCarrier”. capacity and capacity_units default to None. The capacity units are looked up from the ship type, and the formula returns the average emissions factor for the ship type.

hgv_ghg([ghg_units[, refrigerated[, percent_laden[, hgv_type[, tonnage[, unit]]]]]])

If unspecified, refrigerated defaults to False, percent_laden defaults to “Average”, hgv_type defaults to “All”, tonnage defaults to None and the formula returns the average emissions factor for the HGV type, and unit deafults to ‘km’.

rail_freight_ghg([ghg_units[, rail_type]])

If unspecified, rail_type defaults to “FreightTrain”.

sea_tanker_ghg([ghg_units[, ship_type[, capacity[, capacity_unit]]]])

If unspecified, ship_type defaults to “ProductsTanker”. capacity and capacity_units default to None. The capacity units are looked up from the ship type, and the formula returns the average emissions factor for the tanker type.

van_ghg([ghg_units[, van_class[, tonnage[, fuel[, unit]]]]])

If unspecified, van_class defaults to “Average”, tonnage defaults to None and the formula returns the average emissions factor, fuel defaults to “Unknown”, and unit defaults to “km”.

Carbon Intensity database

No API exists to serve GHG intensity data from Defra so we have created a database ourselves, defra_carbon.py. All business transport and freight transport options have been added for 2013.

The tables are:

• Activities

• BusinessBus

• BusinessCarsByMarketSegment

• BusinessCarsBySize

• BusinessFlights

• BusinessFerries

• BusinessMotorbike

• BusinessRail

• BusinessTaxi

• FreightCargoShip

• FreightFlights

• FreightHGV

• FreightRail

• FreightSeaTanker

• FreightVan

Contributing

Please contact Jamie Bull at jamie.bull@oco-carbon.com if you would like to assist in developing this package

To-do list

1. Add other years to the database. Data for 2012 is available in the same format and so should be easy to add. Other years may be more difficult.

2. Create public functions which link distance and carbon calculations. The intended syntax is travel_carbon.travel_carbon(origin, destination, mode, **kwargs)

3. Create the sea_distance() function. Some thought has gone into this so please contact if you would like to contribute.

4. Improve the rail_distance() function. A new data source, choosing the start and end station appropriately.

5. Improve test coverage.