majiayu000 Carbon Calculator
Business Case
Problem Statement
Sustainability requirements demand:
- Tracking embodied carbon
- Comparing material options
- Meeting carbon targets
- Reporting emissions
Solution
Calculate and track embodied carbon for construction materials using standard emission factors.
Technical Implementation
import pandas as pd
from typing import Dict, Any, List, Optional
from dataclasses import dataclass
from enum import Enum
class MaterialCategory(Enum):
CONCRETE = "concrete"
STEEL = "steel"
ALUMINUM = "aluminum"
TIMBER = "timber"
BRICK = "brick"
GLASS = "glass"
INSULATION = "insulation"
PLASTIC = "plastic"
COPPER = "copper"
OTHER = "other"
@dataclass
class CarbonFactor:
material: str
category: MaterialCategory
ec_factor: float # kgCO2e per unit
unit: str
source: str
@dataclass
class MaterialInput:
material_code: str
material_name: str
quantity: float
unit: str
category: MaterialCategory
@dataclass
class CarbonResult:
material_code: str
material_name: str
quantity: float
unit: str
ec_factor: float
embodied_carbon: float # kgCO2e
category: str
# Embodied carbon factors (kgCO2e per unit)
CARBON_FACTORS = {
# Concrete
'concrete_c20': CarbonFactor('Concrete C20', MaterialCategory.CONCRETE, 240, 'm3', 'ICE Database'),
'concrete_c30': CarbonFactor('Concrete C30', MaterialCategory.CONCRETE, 290, 'm3', 'ICE Database'),
'concrete_c40': CarbonFactor('Concrete C40', MaterialCategory.CONCRETE, 350, 'm3', 'ICE Database'),
'concrete_c50': CarbonFactor('Concrete C50', MaterialCategory.CONCRETE, 410, 'm3', 'ICE Database'),
# Steel
'steel_rebar': CarbonFactor('Rebar', MaterialCategory.STEEL, 1.99, 'kg', 'ICE Database'),
'steel_section': CarbonFactor('Steel Section', MaterialCategory.STEEL, 1.55, 'kg', 'ICE Database'),
'steel_sheet': CarbonFactor('Steel Sheet', MaterialCategory.STEEL, 2.03, 'kg', 'ICE Database'),
'steel_stainless': CarbonFactor('Stainless Steel', MaterialCategory.STEEL, 6.15, 'kg', 'ICE Database'),
# Aluminum
'aluminum_general': CarbonFactor('Aluminum General', MaterialCategory.ALUMINUM, 9.16, 'kg', 'ICE Database'),
'aluminum_recycled': CarbonFactor('Aluminum Recycled', MaterialCategory.ALUMINUM, 1.81, 'kg', 'ICE Database'),
# Timber
'timber_softwood': CarbonFactor('Softwood Timber', MaterialCategory.TIMBER, 0.31, 'kg', 'ICE Database'),
'timber_hardwood': CarbonFactor('Hardwood Timber', MaterialCategory.TIMBER, 0.46, 'kg', 'ICE Database'),
'timber_glulam': CarbonFactor('Glulam', MaterialCategory.TIMBER, 0.51, 'kg', 'ICE Database'),
'timber_clt': CarbonFactor('CLT', MaterialCategory.TIMBER, 0.44, 'kg', 'ICE Database'),
'timber_plywood': CarbonFactor('Plywood', MaterialCategory.TIMBER, 0.65, 'kg', 'ICE Database'),
# Masonry
'brick_common': CarbonFactor('Common Brick', MaterialCategory.BRICK, 0.24, 'kg', 'ICE Database'),
'block_concrete': CarbonFactor('Concrete Block', MaterialCategory.BRICK, 0.10, 'kg', 'ICE Database'),
# Glass
'glass_float': CarbonFactor('Float Glass', MaterialCategory.GLASS, 1.44, 'kg', 'ICE Database'),
'glass_double': CarbonFactor('Double Glazing', MaterialCategory.GLASS, 35.0, 'm2', 'ICE Database'),
# Insulation
'insul_mineral': CarbonFactor('Mineral Wool', MaterialCategory.INSULATION, 1.28, 'kg', 'ICE Database'),
'insul_eps': CarbonFactor('EPS', MaterialCategory.INSULATION, 3.29, 'kg', 'ICE Database'),
'insul_xps': CarbonFactor('XPS', MaterialCategory.INSULATION, 3.29, 'kg', 'ICE Database'),
# Other
'copper_pipe': CarbonFactor('Copper Pipe', MaterialCategory.COPPER, 2.71, 'kg', 'ICE Database'),
'pvc_pipe': CarbonFactor('PVC Pipe', MaterialCategory.PLASTIC, 3.10, 'kg', 'ICE Database'),
}
class CarbonCalculator:
"""Calculate embodied carbon for construction."""
def __init__(self, project_name: str):
self.project_name = project_name
self.materials: List[MaterialInput] = []
self.results: List[CarbonResult] = []
self.custom_factors: Dict[str, CarbonFactor] = {}
def add_custom_factor(self,
code: str,
name: str,
category: MaterialCategory,
ec_factor: float,
unit: str,
source: str = "Custom"):
"""Add custom carbon factor."""
self.custom_factors[code] = CarbonFactor(
material=name,
category=category,
ec_factor=ec_factor,
unit=unit,
source=source
)
def get_factor(self, material_code: str) -> Optional[CarbonFactor]:
"""Get carbon factor for material."""
# Check custom first
if material_code in self.custom_factors:
return self.custom_factors[material_code]
# Check standard factors
code_lower = material_code.lower().replace('-', '_').replace(' ', '_')
return CARBON_FACTORS.get(code_lower)
def add_material(self,
material_code: str,
material_name: str,
quantity: float,
unit: str,
category: MaterialCategory = MaterialCategory.OTHER):
"""Add material to calculation."""
self.materials.append(MaterialInput(
material_code=material_code,
material_name=material_name,
quantity=quantity,
unit=unit,
category=category
))
def calculate(self) -> List[CarbonResult]:
"""Calculate embodied carbon for all materials."""
self.results = []
for mat in self.materials:
factor = self.get_factor(mat.material_code)
if factor:
# Check unit compatibility
if factor.unit == mat.unit:
ec = mat.quantity * factor.ec_factor
else:
# Assume conversion needed - simplified
ec = mat.quantity * factor.ec_factor
else:
# Use default factor based on category
default_factors = {
MaterialCategory.CONCRETE: 300,
MaterialCategory.STEEL: 1.8,
MaterialCategory.ALUMINUM: 9.0,
MaterialCategory.TIMBER: 0.4,
MaterialCategory.BRICK: 0.2,
MaterialCategory.GLASS: 1.5,
MaterialCategory.INSULATION: 2.0,
MaterialCategory.OTHER: 1.0
}
ec_factor = default_factors.get(mat.category, 1.0)
ec = mat.quantity * ec_factor
self.results.append(CarbonResult(
material_code=mat.material_code,
material_name=mat.material_name,
quantity=mat.quantity,
unit=mat.unit,
ec_factor=factor.ec_factor if factor else 0,
embodied_carbon=round(ec, 2),
category=mat.category.value
))
return self.results
def get_total_carbon(self) -> float:
"""Get total embodied carbon (kgCO2e)."""
return sum(r.embodied_carbon for r in self.results)
def get_carbon_by_category(self) -> Dict[str, float]:
"""Get carbon breakdown by category."""
by_category = {}
for r in self.results:
if r.category not in by_category:
by_category[r.category] = 0
by_category[r.category] += r.embodied_carbon
return {k: round(v, 2) for k, v in by_category.items()}
def compare_alternatives(self,
original_code: str,
original_qty: float,
alternative_code: str,
alternative_qty: float) -> Dict[str, Any]:
"""Compare carbon impact of material alternatives."""
original_factor = self.get_factor(original_code)
alt_factor = self.get_factor(alternative_code)
if not original_factor or not alt_factor:
return {}
original_carbon = original_qty * original_factor.ec_factor
alt_carbon = alternative_qty * alt_factor.ec_factor
savings = original_carbon - alt_carbon
return {
'original_material': original_factor.material,
'original_carbon': round(original_carbon, 2),
'alternative_material': alt_factor.material,
'alternative_carbon': round(alt_carbon, 2),
'carbon_savings': round(savings, 2),
'savings_percent': round(savings / original_carbon * 100, 1) if original_carbon > 0 else 0
}
def generate_report(self) -> Dict[str, Any]:
"""Generate carbon report."""
if not self.results:
self.calculate()
total = self.get_total_carbon()
by_category = self.get_carbon_by_category()
# Find top contributors
sorted_results = sorted(self.results, key=lambda x: x.embodied_carbon, reverse=True)
top_5 = sorted_results[:5]
# Convert to tonnes
total_tonnes = total / 1000
return {
'project': self.project_name,
'total_kgCO2e': round(total, 2),
'total_tCO2e': round(total_tonnes, 2),
'material_count': len(self.results),
'by_category': by_category,
'top_contributors': [
{
'material': r.material_name,
'carbon': r.embodied_carbon,
'percentage': round(r.embodied_carbon / total * 100, 1) if total > 0 else 0
}
for r in top_5
]
}
def suggest_reductions(self) -> List[Dict[str, Any]]:
"""Suggest carbon reduction opportunities."""
if not self.results:
self.calculate()
suggestions = []
for r in self.results:
# Steel -> Timber
if r.category == 'steel' and r.embodied_carbon > 1000:
suggestions.append({
'material': r.material_name,
'current_carbon': r.embodied_carbon,
'suggestion': 'Consider timber alternative where structurally feasible',
'potential_reduction': '60-80%'
})
# Standard concrete -> Low carbon
if r.category == 'concrete' and r.embodied_carbon > 5000:
suggestions.append({
'material': r.material_name,
'current_carbon': r.embodied_carbon,
'suggestion': 'Use low-carbon concrete mix with SCMs',
'potential_reduction': '20-40%'
})
# Virgin aluminum -> Recycled
if r.category == 'aluminum':
suggestions.append({
'material': r.material_name,
'current_carbon': r.embodied_carbon,
'suggestion': 'Specify recycled aluminum content',
'potential_reduction': '70-80%'
})
return suggestions
def export_to_excel(self, output_path: str) -> str:
"""Export carbon calculation to Excel."""
if not self.results:
self.calculate()
report = self.generate_report()
with pd.ExcelWriter(output_path, engine='openpyxl') as writer:
# Summary
summary_df = pd.DataFrame([{
'Project': self.project_name,
'Total kgCO2e': report['total_kgCO2e'],
'Total tCO2e': report['total_tCO2e'],
'Materials': report['material_count']
}])
summary_df.to_excel(writer, sheet_name='Summary', index=False)
# Details
details_df = pd.DataFrame([
{
'Material Code': r.material_code,
'Material': r.material_name,
'Quantity': r.quantity,
'Unit': r.unit,
'EC Factor': r.ec_factor,
'Embodied Carbon (kgCO2e)': r.embodied_carbon,
'Category': r.category
}
for r in self.results
])
details_df.to_excel(writer, sheet_name='Materials', index=False)
# By Category
cat_df = pd.DataFrame([
{'Category': k, 'kgCO2e': v}
for k, v in report['by_category'].items()
])
cat_df.to_excel(writer, sheet_name='By Category', index=False)
# Suggestions
suggestions = self.suggest_reductions()
if suggestions:
sug_df = pd.DataFrame(suggestions)
sug_df.to_excel(writer, sheet_name='Reduction Ideas', index=False)
return output_path
Quick Start
# Initialize calculator
calc = CarbonCalculator("Office Building A")
# Add materials
calc.add_material("concrete_c30", "Foundation Concrete", 500, "m3", MaterialCategory.CONCRETE)
calc.add_material("steel_rebar", "Reinforcement", 50000, "kg", MaterialCategory.STEEL)
calc.add_material("steel_section", "Structural Steel", 200000, "kg", MaterialCategory.STEEL)
calc.add_material("glass_double", "Facade Glazing", 1500, "m2", MaterialCategory.GLASS)
# Calculate
results = calc.calculate()
# Get report
report = calc.generate_report()
print(f"Total: {report['total_tCO2e']} tCO2e")
Common Use Cases
1. Compare Alternatives
comparison = calc.compare_alternatives(
"steel_section", 100000,
"timber_glulam", 80000
)
print(f"Savings: {comparison['savings_percent']}%")
2. Get Suggestions
suggestions = calc.suggest_reductions()
for s in suggestions:
print(f"{s['material']}: {s['suggestion']}")
3. Category Breakdown
by_category = calc.get_carbon_by_category()
for cat, carbon in by_category.items():
print(f"{cat}: {carbon:,.0f} kgCO2e")
Resources
- ICE Database: Inventory of Carbon & Energy
- DDC Book: Chapter 5.1 - Sustainability Reporting