Case study – Environmental impacts – Energy and utilities

Identifying opportunities across the network

While the initial focus for increasing our energy efficiency has been at premises where Tube Lines is responsible for paying energy and utility bills, we are also sharing and developing ideas with London Underground for saving energy across depots, stations and wider areas of the network where we are not responsible for paying the energy bills but our work could help improve energy efficiency.

Energy-efficient station

In 2007, we presented a proposal for an energy-efficient station to London Underground, identifying 22 potential initiatives with an estimated annual saving of over 2,000 MWh of energy and 900 tonnes of CO₂. “This covered a range of potential measures, from getting rid of redundant machines to introducing intelligent escalator switches that turn escalators on when they are needed instead of leaving them running all the time,” explains Martin Collett, New Works Project Manager. “Our proposals are still under review and our discussions have broadened to take in a wider range of energy-saving opportunities, covering infrastructure as well as stations. All of this work is at the scoping and development stages. We are looking forward to working with London Underground to improve energy efficiency, trialling different and new techniques and taking forward those that work and prove to be compatible with the infrastructure.”

Other suggestions include intelligent metering and lighting and assessing the potential for installing wind turbines and solar panels at depots.

Tunnel heat

Heat in tunnels is also being investigated as a potential energy source. One idea is to install heat exchangers in tunnel walls to capture and transfer tunnel heat and use it, for example, to heat water at stations.

Another new initiative is a partnership with engineering academics from Cambridge University and across Europe to look at new, energy-efficient ways of monitoring and analysing the Tube’s ageing infrastructure. For example, we are considering installing miniature wind turbines that turn when a train approaches, to power equipment which can record data on the state of the tunnel walls.

We are also investigating the potential of light emitting diode (LED) technology to reduce heat levels in train carriages.

Lighting the network

Meanwhile, our efforts to improve the energy efficiency of lighting on the network continue. At stations we have introduced long-life lamps that will last eight years, compared to 12 months for traditional lamps.

As part of a trial in 2007 a hundred energy-saving LED lamps were installed on the Northern line for use in signals. Because safety regulations dictate that these signals must be permanently lit, a light with a longer life expectancy – over a year compared to six months – could bring real savings. We also developed a prototype long-life lighting unit to replace fluorescent lighting in the tunnels.