How Much Energy Is Enough? - The Renaissance of Renewable Energy - page 64

our opportunity, as my friends and I turned the deserted streets of Ferrara into our own
roller-skating park.
Miss Bissi (or rather her source) was wrong about oil running out in forty years, but
she was right to point out that it was a limited resource. This knowledge has since become
commonplace. Wheredoubtarises andexpertsdisagree isontheamountofoilthatremains
underground. Forecasts of oil reserves have been revised several times since the 1970s,
as new fields have been discovered and technology improved, allowing further extraction
from existing fields. Annual global oil production actually increased from 2.9 billion tons
in 1973 to more than 4 billion tons in 2010 (IEA 2012a ). At current rates of production,
known oil reserves will last at least fifty years (BP 2011, 2012 ) or perhaps as long as a
century (Maugeri 2009 ).
Energy experts rarely talk about a moment when oil will run out, like a well that
suddenly runs dry. Rather, most discussions about the future of oil focus on when
production will reach its peak. From an economic point of view, this moment is far more
significant than the day when the last drop is extracted. As soon as it becomes apparent
that oil production is decreasing, the price of oil will soar, as speculators and governments
buy up stocks. The idea of 'peak oil' was first introduced by the geophysicist Marion King
Hubbert in 1956. Since then, the Hubbert Peak Curve, a parabola tracking a steep rise in
oil production, its peak, and subsequent sharp decline, has become an iconic symbol of our
energy predicament.
Some analysts claim that we are very close to peak oil, or even that we have reached
it already. Others point out that oil production has steadily increased in recent years, so a
global peak or plateau is not yet in sight (Maugeri 2011 ; Murray and King 2012 ; Zecca and
Zulberti 2006 ). The moment of peak oil is very difficult to predict, and we will probably
not know it until it has passed. There are three main reasons for this uncertainty.
First, new technology is emerging that allows far more oil to be extracted from existing
fields. At present, only 10-15 per cent of the oil in a reservoir comes out spontaneously
after perforation. This is known as primary production. Once the natural internal pressure
is reduced, water or gas is injected into the reservoir to push more oil towards the wells.
This method allows 20-40 per cent of the oil to be recovered (secondary production). More
recent methods, such as the injection of chemicals or bacteria that dilute the remaining oil,
have raised production to 60 per cent of the reservoir (tertiary production).
Second, many scientists and engineers are confident that new reservoirs will be
discovered. However, experience suggests that we are unlikely to stumble upon any giant
oil field to rival the Ghawar field in Saudi Arabia, as the rate of oil field discovery has
declined over the last thirty years, despite huge advances in the technology of exploration