Efficiency Could Cut World Energy
Use Over 70 Percent
Feb 3, 2011 - Helen Knight - New Scientist
Simple changes like installing better building insulation
could cut the world's energy demands by three-quarters,
according to a new study.
Discussions about reducing greenhouse gas emissions
usually concentrate on cleaner ways of generating
energy: that's because they promise that we can lower
emissions without having to change our energy-hungry
ways. But whereas new generation techniques take
years to come on stream, efficiency can be improved
today, with existing technologies and know-how.
To calculate how much energy could be saved through
such improvements, Julian Allwood and colleagues
at the University of Cambridge analysed the buildings,
vehicles and industry around us and applied "best
practice" efficiency changes to them.
Changes to homes and buildings included triple-glazing
windows and installing 300-millimetre-thick cavity
wall insulation, using saucepan lids when cooking
on the stove top, eliminating hot-water tanks and
reducing the set temperature of washing machines
and dishwashers. In transportation, the weight of
cars was limited to 300 kilograms.
They found that 73 per cent of global energy use
could be saved by introducing such changes.
Many people are unaware of the scale of opportunities
for reducing energy demand, says Allwood. By
showing how global energy demand can fall to
of its current level without any decline in services,
the team hope to redress the balance.
"We think it's pretty unlikely that we'll find
a good response to the threat of global warming on
the supply side alone," Allwood says. "But
if we can make a serious reduction in our demand
for energy, then all the options [for changing the
energy supply] look more realistic."
Not all of the changes might be suitable for immediate
introduction, Allwood admits. "Our 300-kilogram
cars would be at risk in collisions at present if
they met heavier vehicles coming the other way." But
increasingly tough emissions standards for passenger
cars, particularly in Europe, will drive down average
vehicle weights, he says.
Nick Eyre, leader of the Lower Carbon Futures group
at the University of Oxford, says some of the assumptions
made by the team on how much energy could be saved
by efficiency measures may even be overly conservative.
For example, it is possible to design buildings that
are more efficient than the PassivHaus standard they
use as their practical limit. Buildings complying
with this standard must consume less than 15 kilowatt-hours
per square metre of energy in heating each year.
Even so, achieving the 73 per cent cut in energy
consumption will depend on how people use the more
efficient technologies, Eyre says. "A Passivhaus
building will not perform to its design standard
if its occupants open windows when it's cold outside."
However, the team's conclusions are "powerful",
he says, and the suggestion that major investment
should be going into buildings, vehicles and factories
instead of the energy system has major political
"The emphasis on the importance of 'passive
systems' strongly implies that conventional ideas
about the energy system and energy policy need to
be broadened to include the way energy is used, not
just the way it is supplied and converted," Eyre