BBC_Knowledge_2014-06_Asia_100p

High-flying wind turbines have been proposed to

tap into the jet stream’s powerful winds, providing

an immense source of energy. One proposal is for

big floating balls rolling in the wind, another is for

high altitude kites that could power generators.

Another idea is a helicopter-like generator carried

by four huge rotors flying 5 miles (8km) high; a

tether made of aluminium cable would carry

power to the ground and help to keep the device

in place (pictured).

However, there are huge challenges in keeping

control of the high-flying turbines, avoiding

airspace for aircraft, and also keeping track of the

fluctuations in the path of the jet stream.

HARNESSING

THE POWER OF

THE JET STREAM

2010 the jet stream made a very

unusual and strong buckle down into

Pakistan and hit the monsoonal rain belt

with catastrophic results. The jet stream

supercharged the monsoon rains, which

drenched the highlands of Pakistan and

triggered flooding on a colossal scale. It

left a fifth of the country under water and

around 2,000 people dead.

Why the jet stream buckles so violently

is not always clear. Some of it may be down

to chaos in the Earth’s climate, but there

are also other forces at work. “We’ve now

identified a number of factors that can

effect the positions and strength of the jet

stream. In Britain the winter jet stream is

affected by things such as El Niño and La

Niña, fluctuations in the Gulf Stream in the

Atlantic, volcanic eruptions, solar activity,

and the winds in the stratosphere,” says

Adam Scaife.

The path of the jet stream also seems

to drift over the decades. In the 1960s

it was weak and shifted south, and that

gave Britain a run of bitterly cold winters.

In the 1990s the jet stream shifted north

and gave a run of mild and wet winters.

However, there is little evidence that

the jet stream is taking a permanent

The radical designs that

could tap into this abundant

source of energy

Sir Brian Hoskins is studying why the jet stream’s normal path has buckled

Airborne wind power generators like these could

be used to harness the fast-moving winds of the

jet stream

METEOROLOGY

PHOTO:GRANTHAM INSTITUTE/IMPERIAL COLLEGE LONDON, NASA/SVS/GSFC, US AIR FORCE, ALTAEROS ENERGIES