The underground system in London is one of the busiest in the world with over a billion passengers boarding the fast trains on annual basis. Unfortunately, the great popularity and convenience of this mode of transport in the crowded metropolitan, does not lead to a small carbon footprint. In fact, the annual energy consumption of the metro system , trains and stations included, sums up to the mind-blowing £120 million (~$183 million).
In their attempt to reduce this enormous energy use, and cut down the carbon footprint of the system, London city authorities decided to test a new technology, which captures waste energy and recovers it.
Similar to the recovery systems in hybrid and electric vehicles, the new technology uses the so-called “inverter energy capture system“. In short, it captures and recovers energy from the train breaks and sends it back in the form of electricity.
The trails were conduced for one week on one of the busiest Metro lines- Victoria, as part of a much bigger modernization program that is carried out. Within this week, the officials from Transport for London reported an energy saving that translates to the electricity needed to power one station for more than 48 hours, or 1MWh per day.
This new technology is quite a promising start towards lowering the carbon footprint of the Underground system. According to the officials carrying out the initial tests, the amount energy that is saved could reach 5% of the total energy use, or £6 million (US$9 million) in savings per year.
Just a quick reminder here. Two years ago, the Mayor, Boris Johnson, had another idea how to reduce energy usage. Back then he proposed that the heat energy is harnessed, and he claimed that it could cut down London’s emissions by 60%.
Image (c) Transport for London