Motor Gasoline
Diesel Fuel
Natural Gas
Propane
Coal (Anthracite)
Grid Electricity (US Avg)
Gallons
Liters
Per Hour
Per Day
Per Month (Avg)
Per Year
Estimated CO2 Emissions
Emission Rate (Metric):0 kg CO2e / hr
Emission Rate (Imperial):0 lbs CO2e / hr
Total Period Emissions:0 Metric Tons
*Based on standard EPA emission factors. Actual values may vary by specific fuel blend and combustion efficiency.
Understanding Emission Rate Calculations
Calculating emission rates is a fundamental process in environmental engineering, carbon accounting, and regulatory compliance. An Emission Rate defines the mass of pollutant discharged into the atmosphere over a specific period or per unit of activity. This calculator focuses on Carbon Dioxide Equivalent (CO2e) emissions derived from fuel combustion and energy usage.
The Core Formula
The standard methodology used by the EPA and IPCC for estimating emissions involves multiplying activity data by an emission factor. The basic formula is:
E = A × EF × (1 – ER/100)
Where:
E = Emissions (Mass, e.g., kg or lbs)
A = Activity Rate (e.g., gallons of fuel, kWh of energy)
EF = Emission Factor (Specific to the fuel type)
ER = Efficiency Reduction percentage (if applicable controls are in place)
Common Emission Factors
Emission factors vary depending on the chemical composition of the fuel. This calculator uses average factors derived from standard sources like the US EPA GHGRP:
Gasoline: ~8.89 kg CO2 per gallon. High carbon content relative to volume.
Diesel: ~10.16 kg CO2 per gallon. Denser than gasoline, containing more carbon atoms per molecule.
Natural Gas: ~0.05 kg CO2 per cubic foot (or ~53 kg per MMBtu). Often considered a cleaner fossil fuel due to lower carbon intensity.
Grid Electricity: Highly variable. The US national average is approximately 0.38 kg CO2 per kWh, but this changes based on the local energy mix (coal vs. wind/solar).
Why Monitor Emission Rates?
Tracking emission rates is critical for several reasons:
Regulatory Compliance: Facilities must stay below permitted limits (e.g., tons per year) to avoid fines.
Carbon Footprint Analysis: Understanding the rate of emissions helps organizations identify hotspots in their operations.
Efficiency Benchmarking: A rising emission rate for the same output often indicates decreasing equipment efficiency.
How to Improve Results
While this calculator provides a robust estimate based on fuel inputs, industrial calculations often require continuous emission monitoring systems (CEMS) or stoichiometric calculations based on precise fuel analysis. For Scope 1 and Scope 2 reporting, always ensure you are using the most current emission factors for your specific region and reporting year.
// Emission Factors (kg CO2 per Base Unit)
// Gasoline/Diesel/Propane Base: 1 Liter
// Natural Gas Base: 1 Cubic Meter
// Coal Base: 1 kg
// Electricity Base: 1 kWh
var factors = {
gasoline: 2.31, // kg per Liter
diesel: 2.68, // kg per Liter
natural_gas: 1.88, // kg per m3
propane: 1.51, // kg per Liter
coal_anthracite: 2.6, // kg CO2 per kg Coal (Approx)
electricity: 0.386 // kg per kWh (US Avg)
};
// Conversion logic to Base Unit (Liter, m3, kg, kWh)
var unitConversions = {
// Liquids
gallons: 3.78541, // to Liters
liters: 1.0, // to Liters
// Gas
cubic_feet: 0.0283168, // to m3
cubic_meters: 1.0, // to m3
therms: 2.83, // Approx to m3 (varies by pressure/temp, using std conversion)
// Solids
pounds: 0.453592, // to kg
kilograms: 1.0, // to kg
short_tons: 907.185, // to kg
// Energy
kwh: 1.0,
mwh: 1000.0
};
function updateUnits() {
var source = document.getElementById('emissionSource').value;
var unitSelect = document.getElementById('activityUnit');
var activityLabel = document.getElementById('activityLabel');
unitSelect.innerHTML = ""; // Clear existing
if (source === 'gasoline' || source === 'diesel' || source === 'propane') {
activityLabel.innerText = "Fuel Consumption Rate";
addOption(unitSelect, "gallons", "Gallons");
addOption(unitSelect, "liters", "Liters");
} else if (source === 'natural_gas') {
activityLabel.innerText = "Gas Flow Rate";
addOption(unitSelect, "cubic_feet", "Cubic Feet");
addOption(unitSelect, "cubic_meters", "Cubic Meters");
addOption(unitSelect, "therms", "Therms");
} else if (source === 'coal_anthracite') {
activityLabel.innerText = "Mass Burn Rate";
addOption(unitSelect, "pounds", "Pounds (lbs)");
addOption(unitSelect, "kilograms", "Kilograms (kg)");
addOption(unitSelect, "short_tons", "Short Tons");
} else if (source === 'electricity') {
activityLabel.innerText = "Power Usage";
addOption(unitSelect, "kwh", "Kilowatt-hours (kWh)");
addOption(unitSelect, "mwh", "Megawatt-hours (MWh)");
}
}
function addOption(selectElement, value, text) {
var option = document.createElement("option");
option.value = value;
option.text = text;
selectElement.add(option);
}
function calculateEmissionRate() {
var source = document.getElementById('emissionSource').value;
var amountInput = document.getElementById('activityRate').value;
var unit = document.getElementById('activityUnit').value;
var timeBasisHours = parseFloat(document.getElementById('timeBasis').value);
var timeLabel = document.getElementById('timeBasis').options[document.getElementById('timeBasis').selectedIndex].text;
// Validation
if (amountInput === "" || isNaN(amountInput)) {
alert("Please enter a valid numeric Consumption Rate.");
return;
}
var amount = parseFloat(amountInput);
// 1. Convert Input Amount to Base Unit for that source category
var baseAmount = amount * unitConversions[unit];
// 2. Calculate Total Carbon Mass for the input amount
var emissionFactor = factors[source];
var totalKgCO2 = baseAmount * emissionFactor;
// 3. Prepare display values
// If the input is "Per Hour" (value=1), totalKgCO2 is kg/hr.
// If input is "Per Year" (value=8760), totalKgCO2 is kg/yr.
// The user enters a rate "Amount per [TimeBasis]".
// So totalKgCO2 represents the emissions per that TimeBasis.
// Metric Result
var kgResult = totalKgCO2;
// Imperial Result (lbs)
var lbsResult = totalKgCO2 * 2.20462;
// Calculate "Total Emissions per Period" based on the selection
// Actually, the input implies "I use X amount PER [TimeSelection]".
// So the calculator calculates the total emission for that specific period length.
var periodLabel = timeLabel;
var displayMetric = kgResult.toLocaleString('en-US', {maximumFractionDigits: 2}) + " kg CO2e / " + periodLabel.replace("Per ", "").toLowerCase();
var displayImperial = lbsResult.toLocaleString('en-US', {maximumFractionDigits: 2}) + " lbs CO2e / " + periodLabel.replace("Per ", "").toLowerCase();
// Calculate annualized tonnage (Metric Tons)
// If input is per hour, multiply by hours in year (8760) / 1000.
// If input is per year, just divide by 1000.
var annualHours = 8760;
var frequencyRatio = annualHours / timeBasisHours; // How many "periods" in a year
// Wait, logic check:
// User inputs: 100 Gallons (Amount) … Per Month (Time Basis).
// totalKgCO2 = emissions from 100 gallons.
// So the rate is [totalKgCO2] / Month.
// Let's display the rate per Hour (normalized) and Total per Period.
var emissionsPerPeriod = totalKgCO2; // kg per selected period
var emissionsPerHour = totalKgCO2 / timeBasisHours; // kg per hour
// Update DOM
document.getElementById('resultDisplay').style.display = "block";
// Row 1: Rate per selected period
document.getElementById('resMetric').innerHTML = emissionsPerPeriod.toLocaleString('en-US', {maximumFractionDigits: 2}) + " kg CO2e (" + periodLabel + ")";
// Row 2: Imperial
document.getElementById('resImperial').innerHTML = (emissionsPerPeriod * 2.20462).toLocaleString('en-US', {maximumFractionDigits: 2}) + " lbs CO2e (" + periodLabel + ")";
// Row 3: Annualized Metric Tons
// If input is 100 gallons per month. Annual = 100 * 12 * factor.
// annualHours / timeBasisHours gives the multiplier (e.g. 8760/730 = 12).
var annualTons = (emissionsPerPeriod * (8760 / timeBasisHours)) / 1000;
document.getElementById('resTotal').innerHTML = annualTons.toLocaleString('en-US', {maximumFractionDigits: 3}) + " Metric Tons / Year";
}
// Initialize units on load
window.onload = function() {
updateUnits();
};