Purchased Gases

Purchased Gases is a scope 1 emission that accounts for purchased gas stream. Industrial gases are sometimes used in processes such as manufacturing, testing, or laboratory uses. For example, CO2 gas is often used in welding operations. These gases are typically released to the atmosphere after use. Any releases of the seven major greenhouse gases (CO2, CH4, N2O, PFCs, HFCs, SF6, and NF3) must be included in the GHG inventory. Ozone depleting substances, such as CFCs and HCFCs, are regulated internationally and are typically excluded from a GHG inventory or reported as a memo item.

Usage

class atomic6ghg.formulas.purchased_gases.PurchasedGases(wks_data=None)

Calculate emissions from purchased gases

static calculate_co2_emissions_purchased_gases(gwp, purchased_amount)

Calculate CO2 emissions for a gas given material balance inputs

make_co2_equivalent_emissions()

Calculate co2 equivalent emissions

make_purchased_gases()

Calculate CO2 equivalent emissions for each input row

recalc(wks_data: dict) → dict

Execute recalc procedure for PurchasedGases

to_dict()

API to expose _output

to_json()

API to expose _output as JSON

from atomic6ghg.formulas import PurchasedGases

input_data = json.load(
"""
{
  "version": "purchased-gases.1.0.0",
  "purchasedGases": [
    {
      "gas": "ch4",
      "gasGWP": 25,
      "purchasedAmount": 300,
      "CO2EquivalentEmissions": 7500
    },
    {
      "gas": "ch4",
      "gasGWP": 25,
      "purchasedAmount": 400,
      "CO2EquivalentEmissions": 10000
    },
    {
      "gas": "nf3",
      "gasGWP": 17200,
      "purchasedAmount": 30,
      "CO2EquivalentEmissions": 516000
    },
    {
      "gas": "hfc134a",
      "gasGWP": 1430,
      "purchasedAmount": 50,
      "CO2EquivalentEmissions": 71500
    },
    {
      "gas": "c2f6",
      "gasGWP": 12200,
      "purchasedAmount": 70,
      "CO2EquivalentEmissions": 854000
    },
    {
      "gas": "c6f14",
      "gasGWP": 9300,
      "purchasedAmount": 1123,
      "CO2EquivalentEmissions": 10443900
    },
    {
      "gas": "r422a",
      "gasGWP": 3143,
      "purchasedAmount": 595,
      "CO2EquivalentEmissions": 1870085
    },
    {
      "gas": "hfc125",
      "gasGWP": 3500,
      "purchasedAmount": 582,
      "CO2EquivalentEmissions": 2037000
    },
    {
      "gas": "r502",
      "gasGWP": 0,
      "purchasedAmount": 182,
      "CO2EquivalentEmissions": 0
    },
    {
      "gas": "r401b",
      "gasGWP": 14,
      "purchasedAmount": 56,
      "CO2EquivalentEmissions": 784
    },
    {
      "gas": "r422d",
      "gasGWP": 2729,
      "purchasedAmount": 19,
      "CO2EquivalentEmissions": 51851
    }
  ],
  "totalCO2EquivalentEmissions": 7195.284432
}
"""
)

calculated_data = PurchasedGases.to_dict(input_data)

calculated_data['totalCO2EquivalentEmissions']

Parameters:

• input_data - (dict) input data that follows the JSON schema

EPA Equation Analysis

Purchased gases calculates the carbon content (or emission factor) for some complex purchased gas streams.

These complex gas streams include:

Gas
CO2
CH4
N2O
HFC23
HFC32
HFC31
HFC125
HFC134
HFC134a
HFC143
HFC143a
HFC152
HFC152a
HFC161
HFC227ea
HFC236cb
HFC236ea
HFC236fa
HFC245ca
HFC245fa
HFC365mfc
HFC4310mee
SF6
NF3
CF4
C2F6
C3F8
c-C4F8
C4F10
C5F12
C6F14
R-401A
R-401B
R-401C
R-402A
R-402B
R-403B
R-404A
R-406A
R-407A
R-407B
R-407C
R-407D
R-407E
R-408A
R-409A
R-410A
R-410B
R-411A
R-411B
R-413A
R-414A
R-414B
R-417A
R-422A
R-422D
R-423A
R-426A
R-428A
R-434A
R-500
R-502
R-507
R-508A
R-508B

The fundamental calculations for each purchased gas Component are their

\[\text{CO}_2\; Equivalent\; Emissions_{gas} = GWP_{gas} * Purchased Amount_{gas}\]

These equations are derived from Equation 4 from [EPA2015_p11].

where \(\text{CO}_2\; Equivalent\; Emissions_{gas}\) is the total CO2 equivalent in merit unit pounds, \(GWP_{gas}\) is the global warming potential for that gas.

For purchased gases, the \(\text{CO}_2\; Equivalent\; Emissions_{gas}\) in metric tons is calculated. The formula is:

\[\text{CO}_2\; Equivalent\; Emissions_{gas} = \sum_{n=1}^{\infty} \text{CO}_2\; Equivalent\; Emissions_{gas}\]

This equation is derived from [EPA2015_p11].

where \(gas\) is the purchased gas. Note that in atomic6 final values are converted into \(metric \; tons\).

EPA2015_p11(1,2)

EPA, 2015: 2015 EPA Greenhouse Gas Inventory Guidance, Method for Purchased Gases, pp. 11