Module: BrighterPlanet::Computation::CarbonModel

Defined in:
lib/computation/carbon_model.rb

Class Method Summary collapse

Class Method Details

.included(base) ⇒ Object 



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# File 'lib/computation/carbon_model.rb', line 4

def self.included(base)
  base.decide :emission, :with => :characteristics do
    committee :emission do # returns kg CO2e
      quorum 'from electricity use and emission factor', :needs => [:electricity_use, :emission_factor] do |characteristics|
        characteristics[:electricity_use] * characteristics[:emission_factor]
      end
      
      quorum 'default' do
        raise "The emission committee's default quorum should never be called."
      end
    end
    
    committee :emission_factor do # returns kg co2e / kWh
      quorum 'from eGRID subregion', :needs => :egrid_subregion do |characteristics|
        characteristics[:egrid_subregion].electricity_emission_factor
      end
    end
    
    committee :electricity_use do # returns kWh including distribution losses
      quorum 'from compute units, time, electricity intensity, PUE, and eGRID region', :needs => [:ec2_compute_units, :duration_in_hours, :electricity_intensity, :power_usage_effectiveness, :egrid_region] do |characteristics|
        (characteristics[:ec2_compute_units] * characteristics[:duration_in_hours] * characteristics[:electricity_intensity] * characteristics[:power_usage_effectiveness]) / (1 - characteristics[:egrid_region].loss_factor)
      end
    end

    committee :duration_in_hours do
      quorum 'from duration', :needs => :duration do |characteristics|
        characteristics[:duration] / (60 * 60)
      end
    end
    
    committee :power_usage_effectiveness do # returns data center total energy use / IT energy use
      quorum 'default' do
        base.fallback.power_usage_effectiveness
      end
    end
    
    committee :electricity_intensity do # returns kW (average load of IT infrastructure)
      quorum 'default' do
        base.fallback.electricity_intensity
      end
    end
    
    committee :egrid_region do # returns eGRID region
      quorum 'from eGRID subregion', :needs => :egrid_subregion do |characteristics|
        characteristics[:egrid_subregion].egrid_region
      end
    end
    
    committee :egrid_subregion do # returns eGRID subregion
      quorum 'from zip code', :needs => :zip_code do |characteristics|
        characteristics[:zip_code].egrid_subregion
      end
      
      quorum 'default' do
        EgridSubregion.find_by_abbreviation 'US'
      end
    end
    
    committee :duration do # returns seconds
      quorum 'default' do
        base.fallback.duration
      end
    end
    
    committee :ec2_compute_units do # returns compute units (EC2 instances)
      quorum 'default' do
        base.fallback.ec2_compute_units
      end
    end
  end
end