Module: BrighterPlanet::RailTrip::CarbonModel

Defined in:
lib/rail_trip/carbon_model.rb

Class Method Summary collapse

Class Method Details

.included(base) ⇒ Object 



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# File 'lib/rail_trip/carbon_model.rb', line 25

def self.included(base)
  base.decide :emission, :with => :characteristics do
    ### Emission calculation
    # Returns the `emission` estimate (*kg CO<sub>2</sub>e*).
    committee :emission do
      #### From fuel and passengers
      # **Complies:** GHG Protocol, ISO-140641, Climate Registry Protocol
      #
      # - Checks whether the trip occurred during the `timeframe`
      # - Multiplies `diesel use` (*l diesel*) by the `diesel emission factor` (*kg CO<sub>2</sub>e / l diesel*) to give diesel emissions (*kg CO<sub>2</sub>e*)
      # - Multiplies `electricity use` (*kWh*) by the `electricity emission factor` (*kg CO<sub>2</sub>e / kWh electricity*) to give electricity emissions (*kg CO<sub>2</sub>e*)
      # - Adds diesel and electricity emissions to give total emissions (*kg CO<sub>2</sub>e*)
      # - Divides by passengers to give emissions per passenger (*kg CO<sub>2</sub>e*)
      # - If the trip did not occur during the `timeframe`, `emission` is zero
      quorum 'from date, fuel, emission factors, and passengers', :needs => [:diesel_consumed, :diesel_emission_factor, :electricity_consumed, :electricity_emission_factor, :passengers, :date] do |characteristics, timeframe|
        date = characteristics[:date].is_a?(Date) ? characteristics[:date] : Date.parse(characteristics[:date].to_s)
        if timeframe.include? date
          (characteristics[:diesel_consumed] * characteristics[:diesel_emission_factor] + characteristics[:electricity_consumed] * characteristics[:electricity_emission_factor]) / characteristics[:passengers]
        else
          0
        end
      end
    end
    
    ### Diesel emission factor calculation
    # Returns the `diesel emission factor` (*kg CO<sub>2</sub>e / l*).
    committee :diesel_emission_factor do
      #### Default diesel emission factor
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Looks up [Distillate Fuel Oil 2](http://data.brighterplanet.com/fuel_types)'s `emission factor` (*kg CO<sub>2</sub>e / l*).
      quorum 'default' do
        diesel = FuelType.find_by_name "Distillate Fuel Oil 2"
        diesel.emission_factor
      end
    end
    
    ### Electricity emission factor calculation
    # Returns the `electricity emission factor` (*kg CO<sub>2</sub>e / kWh*).
    committee :electricity_emission_factor do
      #### Default electricity emission factor
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # - Looks up the [U.S. Average](http://data.brighterplanet.com/egrid_subregions) `electricity emission factor` (*kg CO<sub>2</sub>e / l*)
      # - Looks up the [U.S. Average](http://data.brighterplanet.com/egrid_regions) grid region `loss factor`
      # - Divides the `electricity emission factor` by (1 - `loss factor`) to account for transmission and distribution losses
      quorum 'default' do
        subregion = EgridSubregion.find_by_abbreviation "US"
        region = subregion.egrid_region
        emission_factor = subregion.electricity_emission_factor / (1 - region.loss_factor)
        emission_factor
      end
    end
    
    ### Diesel consumed calculation
    # Returns the `diesel use` (*l*).
    committee :diesel_consumed do
      #### From distance and diesel intensity
      # **Complies:** GHG Protocol, ISO-140641, Climate Registry Protocol
      #
      # Multiplies `distance` (*km*) by `diesel intensity` (*l / km*) to give *l*.
      quorum 'from distance and diesel intensity', :needs => [:distance, :diesel_intensity] do |characteristics|
        characteristics[:distance] * characteristics[:diesel_intensity]
      end
    end
    
    ### Electricity consumed calculation
    # Returns the `electricity use` (*kWh*).
    committee :electricity_consumed do
      #### From distance and electricity intensity
      # **Complies:** GHG Protocol, ISO-140641, Climate Registry Protocol
      #
      # Multiplies `distance` (*km*) by `electricity intensity` (*kWh / km*) to give *kWh*.
      quorum 'from distance and electricity intensity', :needs => [:distance, :electricity_intensity] do |characteristics|
        characteristics[:distance] * characteristics[:electricity_intensity]
      end
    end
    
    ### Distance calculation
    # Returns the `distance` traveled (*km*).
    committee :distance do
      #### Distance from client input
      # **Complies:** All
      #
      # Uses the client-input `distance` (*km*).
      
      #### Distance from duration and speed
      # **Complies:** GHG Protocol, ISO-140641, Climate Registry Protocol
      #
      # Multiplies the `duration` (*hours*) by the `speed` (*km / hour*) to give *km*.
      quorum 'from duration and speed', :needs => [:duration, :speed] do |characteristics|
        characteristics[:duration] * characteristics[:speed]
      end
      
      #### Distance from rail class
      # **Complies:** GHG Protocol, ISO-140641, Climate Registry Protocol
      #
      # Looks up the [rail class](http://data.brighterplanet.com/rail_classes) `distance`.
      quorum 'from rail class', :needs => :rail_class do |characteristics|
        characteristics[:rail_class].distance
      end
    end
    
    ### Duration calculation
    # Returns the trip's `duration` (*hours*).
      #### Duration from client input
      # **Complies:** All
      #
      # Uses the client-input `duration` (*hours*).
    
    ### Diesel intensity calculation
    # Returns the `diesel intensity` (*l / km*).
    committee :diesel_intensity do
      #### Diesel intensity from rail class
      # **Complies:** GHG Protocol, ISO-140641, Climate Registry Protocol
      #
      # Looks up the [rail class](http://data.brighterplanet.com/rail_classes) `diesel intensity`.
      quorum 'from rail class', :needs => :rail_class do |characteristics|
        characteristics[:rail_class].diesel_intensity
      end
    end
    
    ### Electricity intensity calculation
    # Returns the `electricity intensity` (*kWh / km*).
    committee :electricity_intensity do
      #### Electricity intensity from rail class
      # **Complies:** GHG Protocol, ISO-140641, Climate Registry Protocol
      #
      # Looks up the [rail class](http://data.brighterplanet.com/rail_classes) `electricity intensity`.
      quorum 'from rail class', :needs => :rail_class do |characteristics|
        characteristics[:rail_class].electricity_intensity
      end
    end
    
    ### Speed calculation
    # Returns the average `speed` (*km / hour*).
    committee :speed do
      #### Speed from rail class
      # **Complies:** GHG Protocol, ISO-140641, Climate Registry Protocol
      #
      # Looks up the [rail class](http://data.brighterplanet.com/rail_classes) `speed`.
      quorum 'from rail class', :needs => :rail_class, :complies => [:ghg_protocol, :iso, :tcr] do |characteristics|
        characteristics[:rail_class].speed
      end
    end
    
    ### Passengers calculation
    # Returns the total number of `passengers`.
    committee :passengers do
      #### Passengers from rail class
      # **Complies:** GHG Protocol, ISO-140641, Climate Registry Protocol
      #
      # Looks up the [rail class](http://data.brighterplanet.com/rail_classes) `passengers`.
      quorum 'from rail class', :needs => :rail_class, :complies => [:ghg_protocol, :iso, :tcr]  do |characteristics|
        characteristics[:rail_class].passengers
      end
    end
    
    ### Rail class calculation
    # Returns the [rail class](http://data.brighterplanet.com/rail_classes).
    # This is the type of rail the trip used.
    committee :rail_class do
      #### Rail class from client input
      # **Complies:** All
      #
      # Uses the client-input [rail class](http://data.brighterplanet.com/rail_classes).
      
      #### Default rail class
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Uses an artificial [rail class](http://data.brighterplanet.com/rail_classes) representing the U.S. average.
      quorum 'default', :complies => [:ghg_protocol, :iso, :tcr] do
        RailClass.find_by_name "US average"
      end
    end
    
    ### Date calculation
    # Returns the `date` on which the trip occurred.
    committee :date do
      #### Date from client input
      # **Complies:** All
      #
      # Uses the client-input `date`.
      
      #### Date from timeframe
      # **Complies:** GHG Protocol, ISO-14064-1, Climate Registry Protocol
      #
      # Assumes the trip occurred on the first day of the `timeframe`.
      quorum 'from timeframe', :complies => [:ghg_protocol, :iso, :tcr] do |characteristics, timeframe|
        timeframe.from
      end
    end
    
    ### Timeframe calculation
    # Returns the `timeframe`.
    # This is the period during which to calculate emissions.
      
      #### Timeframe from client input
      # **Complies:** All
      #
      # Uses the client-input `timeframe`.
      
      #### Default timeframe
      # **Complies:** All
      #
      # Uses the current calendar year.
  end
end