Wasted energy may be key to cool-down

Tube passengers sweltering in the summer heatwave may have cooler journeys in the future.

Mayor Ken Livingstone's chief environmental adviser believes he has found a way to reduce temperatures on the Underground.

Allan Jones - described as the "Wayne Rooney of climate change" - thinks wasted energy from powering the network could be used to run a cooler which produces chilled water that creates cool air.

This is then "injected" into tunnels, being dispersed by moving trains and entering carriages through their ventilation systems.

Similar operations are already in use in Woking - where Mr Jones used to work - at Heathrow and at the Royal Free Hospital in Hampstead. He has discussed introducing the system with Transport for London (TfL).

Mr Jones believes cooling units costing up to ?4 million each could be fitted at selected stations or across the network. Such systems are already in use on public transport in Europe, Japan and America.

He said: "If all the stations were to do it, it could reduce temperatures by 10C. That would together change the environment of the Underground simply by making use of energy that we throw away."

He said greenhouse gas emissions would also be reduced because air conditioning units to be fitted in four years' time to trains on sub-surface routes, including the District, Metropolitan and Circle lines, would not have to operate at full capacity.

Mr Jones was charged with reducing greenhouse gas emissions in London by 20 per cent by 2010.

TfL is already considering ways to draw cool water from underground boreholes. Other solutions include adding almost a third more fans and improving 140 ventilation shafts.