Mass is another ultimate resource

[MatthewHeun]

Tania Sousa wrote:

2) I understand that you choose energy as the most important resource :-) but I think that you should acknowledge mass (I justify it better in the comment in the .pdf).

In the .pdf Tania also wrote:

I think that mass should also be here as a master resource (even if you choose to focus on energy in the rest of the book :-). There are properties in mass that are not quantified by their energy or exergy values. We cannot replace steel by cement. Different types of materials have different impacts associated with their production. There are CO2 emissions associated with cement production that are not related with energy use. Stock have mass and "energy services" are provided by mass (stocks and flows) and energy.

[MatthewHeun]

I think a paragraph talking about mass in Ch1 is worthwhile.

Tania rightly points out that we discuss mass in Section 5.1.

[MatthewHeun]

I added a paragraph on mass in Ch1.

At a very fundamental level, 
betterment of the human condition occurs when ingenuity is applied
in economies to the transformation of the size and shape of materials
into useful products.
Thus, both mass (for the materials) and energy (for the transformation)
are crucial for improvement of human life.
Both mass and energy come from the environment.

Although a wide variety of materials are essential for human existence
(see Chapter~\ref{chap:resource_intensity}), 
we say that energy is the ultimate or master resource. 

So I'm closing this issue.