Class: MecsEnergy

Inherits:
ActiveRecord::Base
  • Object
show all
Extended by:
Earth::Model
Defined in:
lib/earth/industry/mecs_energy.rb

Constant Summary collapse

TABLE_STRUCTURE = 
<<-EOS

CREATE TABLE mecs_energies
  (
     name                      CHARACTER VARYING(255) NOT NULL PRIMARY KEY,
     census_region_number      INTEGER,
     naics_code                CHARACTER VARYING(255),
     energy                    FLOAT,
     energy_units              CHARACTER VARYING(255),
     electricity               FLOAT,
     electricity_units         CHARACTER VARYING(255),
     residual_fuel_oil         FLOAT,
     residual_fuel_oil_units   CHARACTER VARYING(255),
     distillate_fuel_oil       FLOAT,
     distillate_fuel_oil_units CHARACTER VARYING(255),
     natural_gas               FLOAT,
     natural_gas_units         CHARACTER VARYING(255),
     lpg_and_ngl               FLOAT,
     lpg_and_ngl_units         CHARACTER VARYING(255),
     coal                      FLOAT,
     coal_units                CHARACTER VARYING(255),
     coke_and_breeze           FLOAT,
     coke_and_breeze_units     CHARACTER VARYING(255),
     other_fuel                FLOAT,
     other_fuel_units          CHARACTER VARYING(255)
  );

EOS
FUELS = 
[:electricity, :residual_fuel_oil, :distillate_fuel_oil,
:natural_gas, :lpg_and_ngl, :coal, :coke_and_breeze, :other_fuel]

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Earth::Model

extend_mining, extended, registry

Class Method Details

.find_by_naics_code(code) ⇒ Object

Find the first record whose naics_code matches code and that has valid fuel ratios. If no record found chop off the last character of code and try again, and so on.



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# File 'lib/earth/industry/mecs_energy.rb', line 44

def self.find_by_naics_code(code)
  find_by_naics_code_and_census_region_number(code, nil)
end

.find_by_naics_code_and_census_region_number(code, number, original_number = number) ⇒ Object

Find the first record whose census_region_number matches number, whose naics_code matches code, and that has valid fuel ratios. If none found and we know census region number, try looking nationwide If none found and looking nationwide, chop off the last character of code and try again looking in census region And so on



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# File 'lib/earth/industry/mecs_energy.rb', line 52

def self.find_by_naics_code_and_census_region_number(code, number, original_number = number)
  if code.blank?
    record = nil
  else
    code = Industry.format_naics_code code
    candidate = where(:census_region_number => number, :naics_code => code).first
    
    if candidate.try(:fuel_ratios).present?
      record = candidate
    elsif number.present?
      record = find_by_naics_code_and_census_region_number(code, nil, original_number)
    else
      record = find_by_naics_code_and_census_region_number(code[0..-2], original_number)
    end
  end
  record
end

Instance Method Details

#fuel_ratios ⇒ Object 



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# File 'lib/earth/industry/mecs_energy.rb', line 70

def fuel_ratios
  # Don't return a ratio if reported total energy was withheld
  if energy.to_f > 0
    # Calculate the sum of all fuels and note if any were withheld
    withheld = 0
    fuels_sum = MecsEnergy::FUELS.inject(0) do |sum, fuel|
      (value = send("#{fuel}")).nil? ? withheld = 1 : sum += value
      sum
    end
    
    # If energy > sum of all fuels and some fuels were withheld, calculate fuel ratios as fraction of energy
    # and attribute the disparity between energy and sum of all fuels to the dirtiest fuel that was withheld
    if energy > fuels_sum and withheld == 1
      ratios = MecsEnergy::FUELS.inject({}) do |r, fuel|
        fuel_use = send("#{fuel}")
        r[fuel] = fuel_use.present? ? fuel_use / energy : nil
        r
      end
      
      dirtiest_withheld = ([:coal, :other_fuel, :coke_and_breeze, :residual_fuel_oil, :distillate_fuel_oil, :lpg_and_ngl, :natural_gas] & ratios.select{|k,v| v.nil?}.keys).first
      ratios[dirtiest_withheld] = (energy - fuels_sum) / energy
      ratios.delete_if{ |fuel, ratio| ratio.to_f == 0.0 }
    # Otherwise calculate ratios as fraction of sum of all fuels, skipping any fuels that were withheld
    else
      ratios = MecsEnergy::FUELS.inject({}) do |r, fuel|
        fuel_use = send("#{fuel}")
        r[fuel] = fuel_use / fuels_sum if fuel_use.to_f > 0
        r
      end
      ratios.keys.any? ? ratios : nil
    end
  end
end