Module: BrighterPlanet::Automobile::CarbonModel

Defined in:
lib/automobile/carbon_model.rb

Class Method Summary collapse

Class Method Details

.included(base) ⇒ Object 



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# File 'lib/automobile/carbon_model.rb', line 27

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
      #### Emission from fuel
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # Multiplies `fuel consumed` (*l*) by the `emission factor` (*kg CO<sub>2</sub>e / l*) to give *kg CO<sub>2</sub>e*.
      quorum 'from fuel', :needs => [:fuel_consumed, :emission_factor], :appreciates => :fuel_type, :complies => [:ghg_protocol, :iso] do |characteristics|
        if characteristics[:fuel_type].andand.code == AutomobileFuelType::CODES[:electricity]
          0.0
        else
          characteristics[:fuel_consumed] * characteristics[:emission_factor]
        end
      end
      
      #### Emission from default
      # **Complies:**
      #
      # Displays an error message if the previous method fails.
      quorum 'default' do
        raise "The emission committee's default quorum should never be called"
      end
    end
    
    ### Emission factor calculation
    # Returns the `emission factor` (*kg CO<sub>2</sub>e / l*)
    committee :emission_factor do
      #### Emission factor from fuel type
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # Looks up the automobile [fuel type](http://data.brighterplanet.com/fuel_types) `emission factor` (*kg CO2e / l*)
      quorum 'from fuel type', :needs => :fuel_type, :complies => [:ghg_protocol, :iso] do |characteristics|
        characteristics[:fuel_type].emission_factor
      end
      
      #### Default emission factor
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # Uses a default `emission factor` of 2.49 *kg CO<sub>2</sub>e / l*, calculated from [EPA (2010)](http://www.epa.gov/climatechange/emissions/usinventoryreport.html)
      quorum 'default', :complies => [:ghg_protocol, :iso] do
        20.781.pounds_per_gallon.to(:kilograms_per_litre)
      end
    end
    
    ### Fuel consumed calculation
    # Returns the `fuel consumed` (*l*).
    committee :fuel_consumed do
      #### Fuel consumed from fuel efficiency and distance
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # Divides the `distance` (*km*) by the `fuel efficiency` (*km / l*) to give *l*.
      quorum 'from fuel efficiency and distance', :needs => [:fuel_efficiency, :distance], :complies => [:ghg_protocol, :iso] do |characteristics|
        characteristics[:distance] / characteristics[:fuel_efficiency]
      end
    end
    
    ### Distance calculation
    # Returns the `distance` (*km*).
    # This is the distance the automobile travelled during the `active subtimeframe`.
    committee :distance do
      #### Distance from annual distance
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # Multiplies the `annual distance` (*km*) by the fraction of the calendar year in which the `timeframe` falls that overlaps with the `active subtimeframe`.
      quorum 'from annual distance', :needs => [:annual_distance, :active_subtimeframe], :complies => [:ghg_protocol, :iso] do |characteristics, timeframe|
        characteristics[:annual_distance] * (characteristics[:active_subtimeframe] / timeframe.year)
      end
    end
    
    ### Annual distance calculation
    # Returns the `annual distance` (*km*).
    # This is the distance the automobile would travel if it were in use for the entire calendar year in which the `timeframe` falls.
    # Note that if either `acquisition` or `retirement` occurs during the calendar year in which the `timeframe` falls then `annual distance` will be MORE THAN the distance the automobile actually travelled during that calendar year.
    committee :annual_distance do
      #### Annual distance from annual distance estimate
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # Uses the `annual distance estimate` (*km*).
      quorum 'from annual distance estimate', :needs => :annual_distance_estimate, :complies => [:ghg_protocol, :iso] do |characteristics|
        characteristics[:annual_distance_estimate]
      end
      
      #### Annual distance from weekly distance
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # Divides the `weekly distance estimate` (*km*) by 7 and multiplies by the number of days in the calendar year in which the `timeframe` falls.
      quorum 'from weekly distance estimate and timeframe', :needs => :weekly_distance_estimate, :complies => [:ghg_protocol, :iso] do |characteristics, timeframe|
        (characteristics[:weekly_distance_estimate] / 7 ) * timeframe.year.days
      end
      
      #### Annual distance from daily distance
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # Multiplies the `daily distance estimate` (*km*) by the number of days in the calendar year in which the `timeframe` falls.
      quorum 'from daily distance estimate and timeframe', :needs => :daily_distance_estimate, :complies => [:ghg_protocol, :iso] do |characteristics, timeframe|
        characteristics[:daily_distance_estimate] * timeframe.year.days
      end
      
      #### Annual distance from daily duration and speed
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # * Multiplies the `daily duration` (*hours*) by the `speed` (*km / hour*) to give *km*
      # * Multiplies the result by the number of days in the calendar year in which the `timeframe` falls.
      quorum 'from daily duration, speed, and timeframe', :needs => [:daily_duration, :speed], :complies => [:ghg_protocol, :iso] do |characteristics, timeframe|
        characteristics[:daily_duration] * characteristics[:speed] * timeframe.year.days
      end
      
      #### Annual distance from size class
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # Looks up the automobile [size class](http://data.brighterplanet.com/automobile_size_classes) `annual distance` (*km*).
      quorum 'from size class', :needs => :size_class, :complies => [:ghg_protocol, :iso] do |characteristics|
        characteristics[:size_class].annual_distance
      end
      
      #### Annual distance from fuel type
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # Looks up the [fuel type](http://data.brighterplanet.com/fuel_types) `annual distance` (*km*).
      quorum 'from fuel type', :needs => :fuel_type, :complies => [:ghg_protocol, :iso] do |characteristics|
        characteristics[:fuel_type].annual_distance
      end
      
      #### Default annual distance
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # Uses an `annual distance` of 19,021 *km*, calculated from total US automobile vehicle miles travelled and number of automobiles.
      quorum 'default', :complies => [:ghg_protocol, :iso] do
        11819.miles.to(:kilometres)
      end
    end
    
    ### Annual distance estimate calculation
    # Returns the client-input `annual distance estimate` (*km*).
    # This is the average distance the automobile travels each week.
    
    ### Weekly distance estimate calculation
    # Returns the client-input `weekly distance estimate` (*km*).
    # This is the average distance the automobile travels each week.
    
    ### Daily distance estimate calculation
    # Returns the client-input `daily distance estimate` (*km*).
    # This is the average distance the automobile travels each day.
    
    ### Daily duration calculation
    # Returns the client-input `daily duration` (*hours*).
    
    ### Fuel efficiency calculation
    # Returns the `fuel efficiency` (*km / l*)
    committee :fuel_efficiency do
      #### Fuel efficiency from client input
      # **Complies:** All
      #
      # Uses the client-input `fuel efficiency` (*km / l*).
      
      #### Fuel efficiency from make model year variant and urbanity
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # * Looks up the city and highway fuel efficiencies of the automobile [make model year variant](http://data.brighterplanet.com/automobile_variants) (*km / l*)
      # * Calculates the harmonic mean of those fuel efficiencies, weighted by `urbanity`
      quorum 'from make model year variant and urbanity', :needs => [:make_model_year_variant, :urbanity], :complies => [:ghg_protocol, :iso] do |characteristics|
        fuel_efficiency_city = characteristics[:make_model_year_variant].fuel_efficiency_city
        fuel_efficiency_highway = characteristics[:make_model_year_variant].fuel_efficiency_highway
        urbanity = characteristics[:urbanity]
        if fuel_efficiency_city.present? and fuel_efficiency_highway.present?
          1.0 / ((urbanity / fuel_efficiency_city) + ((1.0 - urbanity) / fuel_efficiency_highway))
        end
      end
      
      #### Fuel efficiency from make model year and urbanity
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # * Looks up the city and highway fuel efficiencies of the automobile [make model year](http://data.brighterplanet.com/automobile_model_years) (*km / l*)
      # * Calculates the harmonic mean of those fuel efficiencies, weighted by `urbanity`
      quorum 'from make model year and urbanity', :needs => [:make_model_year, :urbanity], :complies => [:ghg_protocol, :iso] do |characteristics|
        fuel_efficiency_city = characteristics[:make_model_year].fuel_efficiency_city
        fuel_efficiency_highway = characteristics[:make_model_year].fuel_efficiency_highway
        urbanity = characteristics[:urbanity]
        if fuel_efficiency_city.present? and fuel_efficiency_highway.present?
          1.0 / ((urbanity / fuel_efficiency_city) + ((1.0 - urbanity) / fuel_efficiency_highway))
        end
      end
      
      #### Fuel efficiency from make model and urbanity
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # * Looks up the city and highway fuel efficiencies of the automobile [make model](http://data.brighterplanet.com/automobile_models) (*km / l*)
      # * Calculates the harmonic mean of those fuel efficiencies, weighted by `urbanity`
      quorum 'from make model and urbanity', :needs => [:make_model, :urbanity], :complies => [:ghg_protocol, :iso] do |characteristics|
        fuel_efficiency_city = characteristics[:make_model].fuel_efficiency_city
        fuel_efficiency_highway = characteristics[:make_model].fuel_efficiency_highway
        urbanity = characteristics[:urbanity]
        if fuel_efficiency_city.present? and fuel_efficiency_highway.present?
          1.0 / ((urbanity / fuel_efficiency_city) + ((1.0 - urbanity) / fuel_efficiency_highway))
        end
      end
      
      #### Fuel efficiency from size class, hybridity multiplier, and urbanity
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # * Looks up the automobile [size class](http://data.brighterplanet.com/automobile_makes) city and highway fuel efficiency (*km / l*)
      # * Calculates the harmonic mean of those fuel efficiencies, weighted by `urbanity`
      # * Multiplies the result by the `hybridity multiplie`r
      quorum 'from size class, hybridity multiplier, and urbanity', :needs => [:size_class, :hybridity_multiplier, :urbanity], :complies => [:ghg_protocol, :iso] do |characteristics|
        fuel_efficiency_city = characteristics[:size_class].fuel_efficiency_city
        fuel_efficiency_highway = characteristics[:size_class].fuel_efficiency_highway
        urbanity = characteristics[:urbanity]
        if fuel_efficiency_city.present? and fuel_efficiency_highway.present?
          (1.0 / ((urbanity / fuel_efficiency_city) + ((1.0 - urbanity) / fuel_efficiency_highway))) * characteristics[:hybridity_multiplier]
        end
      end
      
      #### Fuel efficiency from make year and hybridity multiplier
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # * Looks up the automobile [make year](http://data.brighterplanet.com/automobile_make_years) combined fuel efficiency (*km / l*)
      # * Multiplies the combined fuel efficiency by the `hybridity multiplier`
      quorum 'from make year and hybridity multiplier', :needs => [:make_year, :hybridity_multiplier], :complies => [:ghg_protocol, :iso] do |characteristics|
        characteristics[:make_year].fuel_efficiency * characteristics[:hybridity_multiplier]
      end
      
      #### Fuel efficiency from make and hybridity multiplier
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # * Looks up the automobile [make](http://data.brighterplanet.com/automobile_makes) combined fuel efficiency (*km / l*)
      # * Multiplies the combined fuel efficiency by the `hybridity multiplier`
      quorum 'from make and hybridity multiplier', :needs => [:make, :hybridity_multiplier], :complies => [:ghg_protocol, :iso] do |characteristics|
        if characteristics[:make].fuel_efficiency.nil?
          nil
        else
          characteristics[:make].fuel_efficiency * characteristics[:hybridity_multiplier]
        end
      end
      
      #### Fuel efficiency from hybridity multiplier
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # * Takes a default `fuel efficiency` of 8.58 *km / l*, calculated from total US automobile vehicle miles travelled and gasoline and diesel consumption.
      # * Multiplies the `fuel efficiency` by the `hybridity multiplier`
      quorum 'from hybridity multiplier', :needs => :hybridity_multiplier, :complies => [:ghg_protocol, :iso] do |characteristics|
        20.182.miles_per_gallon.to(:kilometres_per_litre) * characteristics[:hybridity_multiplier]
      end
    end
    
    ### Hybridity multiplier calculation
    # Returns the `hybridity multiplier`.
    # This value may be used to adjust the fuel efficiency based on whether the automobile is a hybrid or conventional vehicle.
    committee :hybridity_multiplier do
      #### Hybridity multiplier from size class, hybridity, and urbanity
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # * Looks up the appropriate city and highway hybridity multipliers for the automobile [size class](http://data.brighterplanet.com/automobile_size_classes)
      # * Calculates the harmonic mean of those multipliers, weighted by `urbanity`
      quorum 'from size class, hybridity, and urbanity', :needs => [:size_class, :hybridity, :urbanity], :complies => [:ghg_protocol, :iso] do |characteristics|
        drivetrain = characteristics[:hybridity] ? :hybrid : :conventional
        urbanity = characteristics[:urbanity]
        size_class = characteristics[:size_class]
        fuel_efficiency_multipliers = {
          :city => size_class.send(:"#{drivetrain}_fuel_efficiency_city_multiplier"),
          :highway => size_class.send(:"#{drivetrain}_fuel_efficiency_highway_multiplier")
        }
        if fuel_efficiency_multipliers.values.any?(&:nil?)
          nil
        else
          1.0 / ((urbanity / fuel_efficiency_multipliers[:city]) + ((1.0 - urbanity) / fuel_efficiency_multipliers[:highway]))
        end
      end
      
      #### Hybridity multiplier from hybridity and urbanity
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # * Looks up the appropriate default city and highway hybridity multipliers
      # * Calculates the harmonic mean of those multipliers, weighted by `urbanity`
      quorum 'from hybridity and urbanity', :needs => [:hybridity, :urbanity], :complies => [:ghg_protocol, :iso] do |characteristics|
        drivetrain = characteristics[:hybridity] ? :hybrid : :conventional
        urbanity = characteristics[:urbanity]
        fuel_efficiency_multipliers = {
          :city => AutomobileSizeClass.fallback.send(:"#{drivetrain}_fuel_efficiency_city_multiplier"),
          :highway => AutomobileSizeClass.fallback.send(:"#{drivetrain}_fuel_efficiency_highway_multiplier")
        }
        1.0 / ((urbanity / fuel_efficiency_multipliers[:city]) + ((1.0 - urbanity) / fuel_efficiency_multipliers[:highway]))
      end
      
      #### Default hybridity multiplier
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # Uses a default `hybridity multiplier` of 1.
      quorum 'default', :complies => [:ghg_protocol, :iso] do
        1.0
      end
    end
    
    ### Hybridity calculation
    # Returns the client-input `hybridity`. This indicates whether the automobile is a hybrid electric vehicle or a conventional vehicle.
    
    ### Size class calculation
    # Returns the client-input automobile [size class](http://data.brighterplanet.com/automobile_size_classes).
    
    ### Speed calculation
    # Returns the average `speed` at which the automobile travels (*km / hour*)
    committee :speed do
      #### Speed from urbanity
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # * Takes average city and highway driving speeds from [EPA (2006)](http://www.epa.gov/fueleconomy/420r06017.pdf) and converts from *miles / hour* to *km / hour*
      # * Calculates the harmonic mean of those speeds, weighted by `urbanity`
      quorum 'from urbanity', :needs => :urbanity, :complies => [:ghg_protocol, :iso] do |characteristics|
        1 / (characteristics[:urbanity] / 19.9.miles.to(:kilometres) + (1 - characteristics[:urbanity]) / 57.1.miles.to(:kilometres)) 
      end
    end
    
    ### Urbanity calculation
    # Returns the `urbanity`.
    # This is the fraction of the total distance driven that occurs on towns and city streets as opposed to highways (defined using a 45 miles per hour "speed cutpoint").
    committee :urbanity do
      #### Urbanity from client input
      # **Complies:** All
      #
      # Uses the client-input `urbanity`.
      
      #### Default urbanity
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # Uses an `urbanity` of 0.43 after [EPA (2009) Appendix A](http://www.epa.gov/otaq/cert/mpg/fetrends/420r09014-appx-a.pdf)
      quorum 'default', :complies => [:ghg_protocol, :iso] do
        0.43
      end
    end
    
    ### Fuel type calculation
    # Returns the `fuel type` used by the automobile.
    committee :fuel_type do
      #### Fuel type from client input
      # **Complies:** All
      #
      # Uses the client-input [fuel type](http://data.brighterplanet.com/fuel_types).
      
      #### Fuel type from make model year variant
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # Looks up the [variant](http://data.brighterplanet.com/automobile_variants) `fuel type`.
      quorum 'from make model year variant', :needs => :make_model_year_variant, :complies => [:ghg_protocol, :iso] do |characteristics|
        characteristics[:make_model_year_variant].fuel_type
      end
    end
    
    ### Active subtimeframe calculation
    # Returns the portion of the `timeframe` that falls between the `acquisition` and `retirement`.
    committee :active_subtimeframe do
      #### Active subtimeframe from timeframe, acquisition, and retirement
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # Uses the portion of the `timeframe` that falls between `acquisition` and `retirement`.
      quorum 'from acquisition and retirement', :needs => [:acquisition, :retirement], :complies => [:ghg_protocol, :iso] do |characteristics, timeframe|
        Timeframe.constrained_new characteristics[:acquisition].to_date, characteristics[:retirement].to_date, timeframe
      end
    end
    
    ### Acquisition calculation
    # Returns the date of the automobile's `acquisition`.
    # This is the date the automobile was put into use.
    committee :acquisition do
      #### Acquisition from client input
      # **Complies:** All
      #
      # Uses the client-input `acquisition`.
      
      #### Acquisition from make model year variant
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # Uses the first day of the client-input automobile [make model year variant](http://data.brighterplanet.com/automobile_variants) year.
      quorum 'from make model year variant', :needs => [:make_model_year_variant], :complies => [:ghg_protocol, :iso] do |characteristics|
        Date.new characteristics[:make_model_year_variant].year, 1, 1
      end
      
      #### Acquisition from make model year
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # Uses the first day of the client-input automobile [make model year](http://data.brighterplanet.com/automobile_model_years) year.
      quorum 'from make model year', :needs => [:make_model_year], :complies => [:ghg_protocol, :iso] do |characteristics|
        Date.new characteristics[:make_model_year].year, 1, 1
      end
      
      #### Acquisition from make year
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # Uses the first day of the client-input automobile [make year](http://data.brighterplanet.com/automobile_make_years) year.
      quorum 'from make year', :needs => [:make_year], :complies => [:ghg_protocol, :iso] do |characteristics|
        Date.new characteristics[:make_year].year, 1, 1
      end
      
      #### Acquisition from timeframe or retirement
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # Uses the first day of the `timeframe`, or the `retirement`, whichever is earlier.
      quorum 'from retirement', :appreciates => :retirement, :complies => [:ghg_protocol, :iso] do |characteristics, timeframe|
        [ timeframe.from, characteristics[:retirement] ].compact.min
      end
    end
    
    ### Retirement calculation
    # Returns the date of the automobile's `retirement`.
    # This is the date the automobile was taken out of use.
    committee :retirement do
      #### Retirement from client input
      # **Complies:** All
      #
      # Uses the client-input `retirement`.
      
      #### Retirement from timeframe or acquisition
      # **Complies:** GHG Protocol, ISO 14064-1
      #
      # Uses the last day of the `timeframe`, or the `acquisition`, whichever is later.
      quorum 'from acquisition', :appreciates => :acquisition, :complies => [:ghg_protocol, :iso] do |characteristics, timeframe|
        [ timeframe.to, characteristics[:acquisition] ].compact.max
      end
    end
    
    ### Make model year variant calculation
    # Returns the client-input automobile [make model year variant](http://data.brighterplanet.com/automobile_variants).
    
    ### Make model year calculation
    # Returns the client-input automobile [make model year](http://data.brighterplanet.com/automobile_model_years).
    
    ### Make model calculation
    # Returns the client-input automobile [make model](http://data.brighterplanet.com/automobile_models).
    
    ### Make year calculation
    # Returns the client-input automobile [make year](http://data.brighterplanet.com/automobile_make_years).
    
    ### Make calculation
    # Returns the client-input automobile [make](http://data.brighterplanet.com/automobile_makes).
    
    ### 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