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In 2012, Professor Daniel B. Müller’s research
group at the Programme of Industrial Ecology
included four PhD candidates and one post
doc. The central research theme was the so-
cial metabolism with a focus on material flow
analysis of the two bulk metals steel and alu-
minium, Norwegian forestry, and Norwegian
aquaculture. Our research on aluminium and
steel included the work of four PhD candidates.
Gang Liu addressed major sustainability chal-
lenges of the aluminium cycle using a systems
approach to characterise material flows on the
global and country level. Furthermore, the full
technological life cycle of this metal and trade
across national boundaries were considered,
which enabled the group to perform an inte-
grated analysis of the material-energy-emis-
sions nexus, and which included system feed-
backs and time lags.
Roja Modaresi looked at how the transporta-
tion sector represents a quality bottleneck in
aluminium recycling, and modelled the global
and regional vehicle fleet in order to assess the
likelihood, timing, and extent of a potential
scrap surplus. She, together with other mem-
bers of the group further developed a com-
ponent-alloy model to forecast the demand
for sink alloys and the supply of source alloys
within the vehicle fleet to assess the effective-
ness of different ELV strategies.
Amund N. Løvik worked on tracking alloying el-
ements and impurities through the aluminium
cycle, investigated how these may put quality
constraints on future recycling, and identified
options to overcome such limitations through
restructuring the system.
The work on aluminium was done in close col-
laboration with IndEcol’s partners Norsk Hydro,
the International Aluminium Institute, and the
European Aluminium Association. The pro-
gramme aims to inform industry and govern-
ments in strategic decision-making related to
aluminium production, recycling, trade, and
climate change mitigation.
Stefan Pauliuk focused on how steel forms the
backbone of our industrialised society. Due to
the long lifetime of steel-containing products,
in-use stocks are a better measure for the serv-
ice provided by this material than the annual
consumption of steel. To make meaningful
long-term forecasts on steel demand, produc-
tion, and the recycling potential, one needs to
understand howmuch steel in stocks is needed
to reach a certain level of human development
and howmuch steel consumption is needed to
maintain these stocks. Pauliuk quantified the
amount of steel in-use for all countries in the
world. The figure below shows a world map
with our estimates on the steel stock in use.
Clearly, the industrialised countries stand out
with a steel stock of often more than ten tons
per capita. It was also found that in many in-
dustrialised countries, stocks have saturated or
are about to saturate in the range of 12-14 tons
per capita. This indicates that a certain amount
of steel in use per person is sufficient to reach
high economic development.
The research group’s work on Norwegian for-
estry and nutrient flows in aquatic ecosystems
and aquaculture included one Post-Doc and
two MSc students:
Post doc Franciska S. Steinhoff investigated
how timber plays an important role as con-
struction material and as renewable energy
source in Norway. Its deployment may help
to reduce overall greenhouse gas emissions
from the building sector. To assess the maxi-
mal emissions mitigation potential of the lim-
ited timber supply, she modelled the timber
flow from forests to Norwegian residential and
non-residential buildings and civil-engineering
constructions using material flow analysis. The
aim of the project is to identify optimal recy-
cling strategies that would allow for an effec-
tive and sustainable cascading use of timber.
First results pointed out that initial use as a
construction material and subsequent appli-
cation as a fibre supply for paper or cardboard
production or as fuel may help to substantially
reduce system wide carbon emissions.
Furthermore, Franciska S. Steinhoff, Shraddha
Mehta, and Magnus I. Vestrum looked into
how phosphorus and nitrogen emissions are
causing eutrophication in aquatic ecosystems.
due to over-fertilization of cultivated land and
insufficient waste water treatment in urban
and rural settlements. In order to mitigate
potential phosphorus scarcity and eutrophica-
tion problems, reliable estimates of phospho-
rus flows, sinks and stocks as well as recycling
strategies and alternative resources need to be
found and linked to an environmental system
analysis. This group of researchers investigated
both anthropogenic and aquatic systems on
the national (Norwegian aquaculture) and in-
ternational scale (Baltic Sea Basin).
Contact person:
Professor Daniel B. Müller
daniel.mueller@ntnu.no
RESEARCH
R SEARCH
Social Metabolism: Material flow analysis of the two bulk metals steel
and aluminium, Norwegian forestry, and Norwegian aquaculture
Figure: Per capita in-use stocks of steel by country in 2008.
Map created by Gang Liu.