The pedal-powered hotel

A green hotel in Copenhagen is claiming a world first by using guests on exercise bikes to generate electricity
Tom Robbins
guardian.co.uk, Wednesday 14 April 2010 13.36 BST

Bright idea ... an iPhone attached to the handlebars shows how much power is being fed into the hotel's system
Forget solar panels and wind turbines, a hotel that bills itself as one of the "greenest" in the world has found a new source of renewable energy – its guests.
From next Monday, those staying at the 366-room Crown Plaza Copenhagen Towers will be encouraged to head down to the gym to spend time on its new fleet of electricity-generating exercise bikes. The bikes have iPhones mounted on the handlebars which monitor how much power is being produced and fed into the mains supply of the hotel. Any guest producing 10 watt hours or more will be rewarded with a free meal.
The scheme is a pilot project that will run for a year, and if successful, could be rolled out to all 21 Crowne Plaza hotels in the UK.
"The electric bikes offer our guests the chance to get fit and help power the hotel at the same time," said Allan Agerholm, the hotel's general manager. "It will be interesting to see how many guests take part and how much electricity we generate."
Getting the free meal is surprisingly easy. The hotel's calculations suggest one guest cycling at 30kmph for an hour will produce around 100 watt hours of electricity, meaning that reaching the threshold for the meal should take only six minutes.
Critics might argue that even those who cycle for a full hour will be making a rather token contribution to the energy use of a huge city hotel – 100 watt hours of energy is only enough to light a single 100 watt bulb for one hour. However the hotel counters that it wanted the target to be "achievable" so as many people as possible take part.
The hotel, which opened in November last year, is attempting to become carbon neutral. It has EU Green Building and Green Key certification and uses a groundwater-based cooling and heating system, low energy lighting and hand dryers, and is covered in solar panels on its south-facing aspects. So will its latest scheme catch on at other hotels around the world?
"Realistically, this isn't a practical way of generating a useful amount of energy, but I certainly wouldn't criticise it," said Alex Randall, a spokesman for the Centre for Alternative Technology. "As a lesson, and a means of public engagement, it's excellent – if you sit someone on a bike, pedalling hard, and show them they are only generating enough to power one lightbulb or TV, is makes them appreciate how difficult energy is to produce, and therefore why we should be careful not to waste it."