travels 10,000 km/year, 33 complete recharges of the battery are
required, corresponding to 1.65 MWh of electricity per car per
year (neglecting various small inefficiencies). If we roll out a
fleet of 10 million of these cars across Australia, the total elec-
tricity requirement is then 16.5 TWh/year.
Australia’s electricity consumption through the National
Energy Market is about 200 TWh/year (http://tinyurl.com/
Aus-electricity-consumption), so the effect of adding a very
large number of small-ish BEVs is not huge. This much addi-
tional sustainably generated electricity could be provided by
new generators amounting to about 2 GW (equivalent to a
single very large power station) operating continuously or 10 GW
operating at a typical 20% availability for solar or wind power.
This is comparable to the total solar and wind generation
capacity in Australia at present (~9 GW from photovoltaics
and ~6 GW from wind), but is very achievable.
Next, what is the quantity of CO 2 emissions avoided by
taking ICEVs off the road? Let’s assume that the CO 2 emissions
associated with manufacturing a BEV or ICEV are about the
same, and just compare the emissions arising from running the
vehicles. A reasonable figure for the exhaust emission of a
modern small-ish ICEV is 125 g/km, so 10 million cars driving
10,000 km/year amounts to 12.5 Mt/year of CO 2 avoided by
our hypothetical replacement BEV fleet.
But what if the electricity powering the BEV fleet was
produced from coal instead of solar or wind power? The amount
of CO 2 emitted by a black-coal-fired
power station is about 900 g/kWh of
electricity, so the electricity demand
of our hypothetical fleet of BEVs (16.5
TWh/year) would send an extra 15
Mt of CO 2 per year into the atmo-
sphere, exceeding the 12.5 Mt of CO 2
saved by replacing ICEVs.
The take-home message is that the
replacement of a very large number of
ICEVs with BEVs is feasible in terms
of the additional electricity required,
but pretty much pointless if the elec-
tricity is generated by burning coal and
emitting the CO 2 produced into the
atmosphere.
The flip side is that even a national
fleet of 10 million small-ish BEVs
corresponds to only a fairly small frac-
tion of the present national electricity
consumption, so much more must be
done to reduce national CO 2 emis-
sions than decarbonising the national
fleet.
MAY/JUNE 2017 | | 29A BEV’s size and range is
determined by the weight
of batteries it needs to carry.The Nissan Leaf is a BEV with a range of ~150 km.babimu/Ado
be