Audi 2012 Annual Report Download - page 152

155
Management Report
140 Audi Group
151 Business and underlying
situation
151 Economic environment
153 Research and development
162 Procurement
162 Production
165 Deliveries and distribution
173 Financial performance
indicators
176 Social and ecological aspects
190 Risks, opportunities
and outlook
201 Disclaimer
public gas distribution network and also transported. That energy can then be used whenever
required, wherever it is most suitable; it can also be converted back into electricity at combined
heat and power stations, to supply the grid. The principle behind the Audi e-gas project will work
in all countries where there is a natural gas mains network.
AUDI E-GAS PROJECT
Additionally, here at Audi we are pursuing another highly promising concept to replace gasoline
and diesel with entirely new biofuels that capture the greenhouse gas carbon dioxide during the
production process. Research continues into the manufacture of synthetic ethanol, or Audi
e-ethanol, and synthetic diesel, or Audi e-diesel, in collaboration with specialist partners. The
starting materials required are water, carbon dioxide, solar energy and special microorganisms.
Like plants, these organisms carry out oxygenic photosynthesis, using sunlight and carbon dioxide
to form carbohydrates and grow. They do not need clean drinking water; saltwater or effluent
are adequate. In this instance the photosynthesis process has been modified so that the micro-
organisms convert the carbon dioxide directly into ethanol or long-chain alkanes. These are
important components of diesel fuel. Audi e-ethanol, which is already being made at a pilot
facility, has the same chemical properties as the bioethanol that has been available on the market
for some time. The crucial advantage in this case is that it is made without biomass. It can be
blended with gasoline from fossil sources or used as the basis for E85 fuel.
One particular area of potential for synthetic diesel is its purity, which allows it to be blended
unrestrictedly with fossil diesel. The local factors that will ultimately apply in the production of
this form of energy give it another crucial advantage over bioethanol. The facilities can be located
on land that is entirely unsuitable for agriculture. Furthermore, the latest forecasts suggest that
the yield is many times higher than for ethanol and diesel from renewable raw materials such as
corn and rapeseed. In addition, the latter are in competition with the cultivation of food crops.
Wind energy
The starting point for the Audi e-gas
project is renewably generated electricity.
Power grid
The wind energy is fed into
the public power grid. Gas network
The e-gas is stored in the public gas
network and can therefore also supply
households and industry with energy
from renewable sources.
CNG filling station
The amount of e-gas fed into the system is
equivalent to the gas supplied to Audi
customers via existing natural gas
filling stations.
Methanation
The hydrogen reacts
with carbon dioxide in
a methanation plant.
The result: e-gas
(synthetic natural gas).
Electrolysis
The electrolysis plant,
which is operated by
wind power, splits
water into oxygen
and hydrogen.
CO
2