Energy - Cost

In general the energy required to produce a material is a large factor in the raw material cost. As a result most materials lie on a line from bottom left (low cost/low energy content) to top right (high cost/large energy content).
It is difficult to assess the environmental impact of using one material over another since there are many factors from production to disposal.
The energy content used to produce a material gives a rough indication of the environmental cost of production
For materials which are energy intensive to produce there are large cost and energy savings by recycling e.g. aluminium cans
Gold is a precious metal which can be sold for a very high price; this means that more energy can be spent in extracting it by mining rocks containing only a small fraction of gold

Measuring the energy content of a material is difficult, but includes:
- the energy required to collect/mine the material
- the energy required to refine, extract or synthesise it
Polymers are made by refining and processing hydrocarbons from oil - the energy used per kilogram is similar to the energy needed to produce many metals
Construction materials such as concrete, brick and woods require relatively little energy to produce them and are thus cheap
Metals are usually extracted from their oxide - this takes up a lot of energy, for example, one twentieth of the total energy consumption in the United States is used to produce aluminium

To select materials which have less environmental impact and contribute less to global warming
To consider environmental impact for one-use disposable products - e.g. disposable gowns, sheeting etc in hospitals are made from paper
To consider environmental impact for high volume, energy-intensive products such as cars

Why is it economic to recycle aluminium cans but less so for steel ones?
Why will new reserves of minerals/oil which are not now economic to mine become economic in the future?
Select materials for a wall/fence around your house.
Select materials for fast-food restaurant eat-in plates, trays, etc
Select materials for bedding for cattle.