Business Times Africa Magazine 2017 /vol 9/ No2 BT2Edition2017_web | Page 60

ENERGY
All roads to sustainable
energy lead to the sun
HUMANS CONSUME 221 TONNES OF COAL, 1,066 BARRELS OF OIL, AND 93,000
METRIC CUBES OF NATURAL GAS PER SECOND.
By Werner van Zyl
Transparent solar cell.
T
hese materials were wonderful for
the industrial revolution that started
in Britain in the 18th century and
made use of “new energy” sources such as
coal and petroleum. At the start of the 21st
century, however, it’s time to reassess the
notion of “new energy”. Fossil fuels have
no place in any long-term sustainable
energy solution for the planet. It needs
to be replaced with renewable energy
sources. But which ones?
Sooner or later humanity needs to
get its head around the fact that the only
long-term sustainable energy solution is
58 Business Times Africa | 2017
EARTH PRESENTLY
CONSUMES ENERGY
AT A RATE OF ABOUT
17.7 TRILLION WATTS
(17 TERAWATT, TW),
THAT WOULD REACH
30 TW BY 2050
solar energy. This is simply borne out by
the immense amount of energy potential
that the sun can provide versus any other
renewable resource such as wind, nuclear,
biomass or geothermal. To place that in
perspective: the theoretical potential of
solar power is 89 terawatts (TW), which
represents more energy striking the Earth’s
surface in 90 minutes (480 Exajoules, EJ)
than the worldwide energy consumption
for the entire year 2001 (430 EJ) from all
other resources combined.
Off-grid solar should be Africa’s energy
future. Off-grid simply means a system