Global Compact International Yearbook Ausgabe 2013

Good Practice
Environment
Audi uses another innovative process
to solve this problem. The hydrogen is
combined with CO 2
in the methanation
facility downstream of the electrolysis
plant to produce synthetic renewable
methane – Audi e-gas. From there, it
can then be fed into the natural gas
network and stored there. It can later
be tapped – anywhere, anytime.
The CO 2
comes from waste gas emitted
by a nearby biomethane plant operated
by EWE, an energy provider. This
biomethane plant runs on organic waste.
The Audi e-gas facility uses the CO 2
as
a raw material for new fuel. Audi e-gas
is thus a climate-neutral fuel – when
combusted in the engine, exactly the
same amount of CO 2
is released as was
previously bound at the e-gas plant.
Depending on the supply of electricity,
the plant in Werlte is expected
to produce some 1,000 metric tons of
e-gas annually while chemically binding
approximately 2,800 metric tons
of CO 2
. These same 1,000 metric tons
of Audi e-gas could power 1,500 Audi
A3 Sportback g-tron vehicles for 15,000
kilometers (9,320.57 miles) per year in
CO 2
-neutral driving.
CO 2
tailpipe emissions for the Audi
A3 g-tron are consequently less than 95
grams per km (152.89 g / mile). When the
Audi A3 g-tron is powered by Audi e-gas,
no more CO 2
is released than was chemically
bound in its production beforehand,
creating a closed loop. Even when one
includes in a comprehensive analysis the
energy required to build the e-gas facility
and wind turbines, CO 2
emissions are
still only 20 grams per km (32.18 g / mile).
The German energy industry could also
benefit in the medium term from the
concept of the Audi e-gas project, as
it provides an answer to the unsolved
question of how to store green power
efficiently and independently of location.
The potential of electricity-gas cogeneration
to store large amounts of wind or
even solar energy can provide powerful
stimuli for the expansion of renewable
energies.
Audi e-ethanol and Audi e-diesel
These projects address an old problem
in search of a solution. Whenever conventional
petroleum-based fuels are combusted,
they release CO 2
and pollute the
atmosphere. Ethanol and diesel from
renewable raw materials such as corn
and rapeseed generally achieve a better
environmental balance.
But these fuel sources compete
with arable land for growing food. As
such, they cannot constitute a long-term
solution for our planet’s skyrocketing
population.
The CO 2
-neutral mobility of tomorrow
necessitates radically different
fuels. Audi is therefore collaborating
on just such a solution with the
American company Joule. In a patented
process, Joule manufactures fuels
with the aid of special microorganisms
in a highly scalable modular system
(SolarConverter®): Audi e-diesel and Audi
e-ethanol.
This process requires either wastewater
or salt water; CO 2
; solar energy;
and special single-celled microorganisms
that are just thousandths of a
millimeter in diameter. Just as plants
do, these organisms carry out oxygenic
photosynthesis. The experts at Joule
have modified these microorganisms
such that they produce ethanol or longchain
alkanes – important components
of diesel fuel – directly from the CO 2
and sunlight. The fuels are removed
from the microorganisms, separated
from the water, and cleaned. This technology
is the basis for Audi e-diesel and
Audi e-ethanol.
In short, e-ethanol is a product with
the same chemical properties as bioethanol.
But e-ethanol is far better, as no
biomass is used in its production. This
e-ethanol can be admixed with fossil fuel
gasoline (e. g., E 10) or, alternatively, can
be used as the basis for E 85 fuel (85 %
ethanol, 15 % gasoline).
In addition to developing Audi
e-ethanol, Audi is partnering with Joule
to manufacture synthetic diesel fuel:
Audi e-diesel. A considerable strength of
Audi e-diesel will lie in its purity.
In contrast to petroleum-based
diesel – a mixture of a great many hydrocarbon
compounds – e-diesel is free
of sulfur and aromatics. This fuel of tomorrow
will also offer excellent ignition
performance thanks to its high cetane
number. And its chemical composition
will permit unlimited blending with
fossil fuel diesel.
Audi and Joule jointly built a
demonstration facility in Hobbs, New
Mexico – a barren region with lots of
sunshine. This facility opened in September
2012. Audi e-ethanol was produced
for the first time in transparent
plastic tubes in early 2013 and manufacture
of Audi e-diesel is expected to
follow in the next few years. Efforts at
the demonstration facility alone illustrate
the clear superiority over conventional
bioethanol. In line with forecasts,
the yield of Audi e-ethanol is some
20 times greater! In addition, regions
that are unsuitable for agriculture such
as deserts could be utilized for energy
production. Commercial production of
the new fuels could begin within the
next five years.
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