Transport for London: escalating issues

Transport for London: escalating issues

Last week a reader wondered if the financial and environmental benefits of switching off an escalator at Victoria Tube station were worth it. Might the benefits be outweighed by the possible effects of doing this, such as creating inconvenience for passengers and perhaps persuading them to take alternative forms of transport that add to congestion and pollution and generate more CO2? He used Transport for London's own recent figures to calculate that the economic value of the energy saved was less than £2 an hour.

TfL provided me with a response. It went like this:

London Underground carried out a study which looked at 65 stations with banks of three escalators, and that found that limiting use of the third escalator to peak times could halve power consumption and CO2 emissions, as well as save up to £500,000 a year across the Tube network. These measures were implemented at selected stations from early November 2009.

There followed some example figures, based on a "typical station" and a 15 metre escalator. If such an escalator operates for 20 hours each day (or 7,300 hours a year) its energy consumption and CO2 emission profile looks like this:

Wattage 29,000 W
Annual Power Consumption 211,700 kWh
Annual Energy cost (based on 7p/KWh): £14,819
Electricity Emission Factor 0.537 kg CO2/kWh
Annual CO2 Emissions 113,683 kg

This is a higher annaul cost than the very highest mentioned in the TfL document my reader quoted from: £14,819 per year compared with a maximum of £12,000, but that figure was from 2008. However, the main point in TfL's reply to me is that if their model 15 metre escalator is run for only nine hours a day instead of 20 - 3,285 hours a year instead of 7,300 - that profile changes as follows:

Wattage 29,000 W
Annual Power Consumption 95,265 kWh
Annual Energy cost (based on 7p/KWh): £6,668.55
Electricity Emission Factor 0.537 kg CO2/kWh
Annual CO2 Emissions 51157 kg
Annual Saving 62,526 kg CO2

TfL's conclusion?

The CO2 emissions savings are considerable, as well as the energy savings (116,435 kWh @ 7p per kWh = £8,150). LU network has 65 'third escalators' so the total estimated annual cost saving is around £520,000.

Taking the running time down from 20 hours to nine means switching the escalator off between five and eight in the morning, ten in the morning and noon, two and four in the afternoon and eight in the evening until midnight.

That's quite a lot of shutting down, and some would argue that it is too much at some of those times of day, especially from the point of view of the very young, the very old and the disabled - a point that has been raised by the Lib Dems' Caroline Pidgeon on behalf of a constituent. Also, the TfL figures don't directly address the main concern of my reader, who wondered if the energy saving benefits of the policy were greater than the drawbacks that might result from it.

These might be hard to calculate with precision, but thinking about it does exercise the mind wonderfully. A final thought: among several interesting comments inspired by the initial post on this subject was one from Dave Cole, who wondered what the saving might be from switching off some of the electronic adverts that line some escalators these days. Good question. Would the power savings be greater than any loss of revenue resulting from advertisers demanding lower rates? We could be here all day...