Ecodata: Values, sources, precision

Data Accuracy

Engineering properties are well characterized.

Environmental properties are not.

Embodied energy

Carbon footprint

Embodied Energy

Energy to product a unit of mass of material

ISO 14040 gives guidelines, but they are vague.

How much can we trust the presented values? Studies suggest 10% variance is optimistic.

To what end?

Although the lack of accuracy is a problem, it depends on the ultimate goals.

We can only make conclusions if differences are significant (much more than 10%).

Often we see ranges to account for lack of accuracy (200-240 MJ/kg, e.g.)

Geo-Economic DataInformation about the resource base from which material is draw, and the rate of exploitation.

Annual World Production is the mass of material extracted annually from ores/feedstock

Reserve, as we know, is current economical sources

Ecoproperties: Material Production

The embodied energy (Hm) is the energy committed to create 1kg of usable material.

CO2 footprint is the release of CO2 into the atmosphere - kg of CO2 for each kg of material produced.

Embodied Energythis is not done by pure thermodynamics, due to inefficiencies in actual processes and scrap waste, and other things

The Input/Output Analysis is used.

The total energy input to the production plant over some period of time is measured; including that already invested in feedstock.

The total output (mass of material) over that same time period is recorded.

The ratio of these two is the MJ/kg Embodied Energy.

Aluminum + AlloysGeo-Economic Data

Annual World Production 33-35 M-tonnes/YrReserve 2.0-2.2 G-tonnes

Eco-properties: material productionEmbodied Energy (primary prod) 200-240 MJ/kg

CO2 footprint (primary prod) 11-13 kg/kgWater usage 125-375 l/kgEco-indicator 740-820 mPoints/kg

Eco-properties: material productionCasting Energy 2.4-2.9 MJ/kg

Casting CO2 footprint 0.14-0.17 kg/kgDeformation process energy 2.4-2.9 MJ/kg

Deformation process CO2 0.19-0.23 kg/kgRecycling

Embodied Energy, recycling 18-21 MJ/kgCO2 footprint, recycling 1.1-1.2 kg/kg

Recycle fraction in supply 35-55%

Embodied energy accounting

Must include the feedstock and its embodied energy in your calculations to get a robust understanding.

Suppose we want to study bottles of soda. First we figure out the feedstock by looking at the energy entering the plant per hour and dividing by the mass of PET produced per hour.

Energy of PET production

Tracking Carbon

Carbon tracking is done similar to energy.

Carbon emissions come from transport, energy generation, feedstocks, and fuels.

Usually expressed as kg of CO2 per kg of material

Tracking Carbon

Plants grow by absorbing CO2 and H2O and converting it to cellulose and lignin etc.

Wood sequesters carbon

Some say the carbon footprint of wood is negative (it removes carbon from atmosphere without releasing it)

Coal

Thinking about sequestering, coal is dervied from plant life. The carbon in the coal was once in the atmosphere.

It does not get a negative footprint because we don’t replace it after use.

A credit is only real if it gets replaced.

KenafKenaf can be grown without fertilizer, and grows fast. It can grow fast enough to convert the carbon used in processes - sometimes over 1 inch per day

Wood

Is wood more like kenaf or coal?

Forests are being removed faster than they are replaced world-wide.

Until stocks are replaced as fast as they are consumed, wood should be viewed more like coal than kenaf.

Data Precision (Al)

Data Precision

The mean value of the previous Aluminum chart is 204 MJ/kg.

The standard deviation is 58 MJ/kg (c. 25%)

If we design on allowables, we include several standard deviations.

e.g. Al embodied energy is 100-300 MJ/kg

Eco-Indicators

Attempts are made to combine energy, water, and emissions into a single ECO-INDICATOR value.

EcoPropertiesMaterials are processed and finished. This adds energy to the product.

Polymers are molded or extruded

Metals are cast, forged, machined

Ceramics are shaped (sintering)

There is energy with each

More steps

We’ve made PET pellets, now we need to make bottles...

Energy for PET Bottle Production

Recylcing and End-of-Life

Now that we’ve made bottles, we can still track them.

They go to the bottling factory, get filled, used, and possibly recycled.

Recycling and End of Life

Recycling

Often (not always) recycled materials result in reduced embodied energy in a produced object.

This is because some of the embodied energy from first life is retained.

Energy for Recycling

Special cases: Precious metals and electronics

Precious metals used in small quantities, but have a high embodied energy, carbon, and cost.

Generally have exception conductivity, resistance to corrosion and thus make good electronics parts.

Same is true of electronics themselves

Electronics & Precious Metals (approx energy)

Component Embodied energy (MJ per...)

Carbon Footprint (kg per...)

Small electronic devices (per kg)

2,000-4,000 200-400

Displays, per sq. m. 3,000-3,750 300-375

Assembling of printed wiring boards (per kg)

120-140 12-14

Batteries (Ni-Cd rechargeable) (per kg)

180-220 18-22

Energy IntensitiesFuel kg OE MJ/liter MJ/kg

CO2, kg/liter

CO2, kg/MJ

CO2, kg/kg

Coal, lignite 0.45 -- 18-22 -- 0.08 1.6

Coal, anthracite 0.72 -- 30-34 -- 0.088 2.9

Crude oil 1.0 38 44 3.1 0.07 3.0

Diesel 1.0 38 44 3.1 0.071 3.2

Gasoline 1.05 35 45 2.9 0.065 2.89

Kerosene 1.0 35 43.8 3.0 0.068 3.0

Ethanol 0.71 23 31 2.8 0.083 2.6

Liquid natural gas 1.2 25 55 3.03 0.055 3.03

Electricity GenerationCountry Fossil Nuclear Renewables

Fossil fuel Efficiency

MJ OE/kw-

hr

CO2 kg/kW-

hr

Australia 92 0 8 33 10.0 0.71

China 83 2 15 32 9.3 0.66

France 10 78 12 40 0.9 0.06

India 81 2.5 16.5 27 10.8 0.77

Japan 61 27 12 41 5.4 0.38

Norway 1 0 99 -- 0 0

United Kingdom

75 19 6 40 6.6 0.47

United States

71 19 10 36 7.1 0.54

Transport

Products are made in cheapest location and then transported to customer

We express energy of transport as energy per ton-km, and CO2 in kg/ton-km

Transport EnergyFuel and vehicle type

Energy (MJ/ton-km)

Carbon (kg/ton-km)

Diesel - ocean shipping 0.16 0.015Diesel - coastal shipping 0.27 0.019

Diesel - rail 0.31 0.022Diesel - 32 ton truck 0.46 0.033Diesel - 14 ton truck 0.90 0.064

Diesel - light goods vehicle 1.36 0.097Gas - family car 2.06 0.14

Diesel - family car 1.60 0.11LPG - family car 3.87 0.18

Gas-Hybrid family car 1.55 0.10Gas - super sports/SUV 4.76 0.31

Kerosene - long haul aircraft 8.30 0.55Kerosene - short haul aircraft 15.0 1.00

Kersosene - helicopter 55.0 3.30

Exploring the dataBar charts vs Bubble Charts

Bar charts show a value for each item

Range of bar shows range of values

Bubble charts show ranges for a material that have two different properties

Watch for logarithmic axes!

Material Property Charts

Give an overview of physical, mechanical, functional properties in a compact way

Reveal aspects of physical origins of properties

Tool for optimized selection of materials to given design requirements

Allow properties of new materials to be displayed and compared with conventional materials

Tensile Modulus of typical materials

Modulus and Density

Metal recycling in current supply (%)

Polymer recycling in current supply (%)

Ceramic recycling in current supply (%)

Natural and Hybrid