Tune in turn off

Power management for white goods could cut down the watts

Dynamic demand is clever stuff - yet so simple that your fridge could do it. Good timing is the key. Scheduling power-hungry activities like heating and laundry ‘off peak’, to avoid stretching the capacity of the grid, is the well-established efficiency principle behind those long-familiar day/night electricity tariffs.

The smart new bit is fine-tuning those timing decisions so they are made moment-by-moment, 24/7 - by the appliances themselves. Or, to be more precise, by a ‘dynamic demand’ control device, which can be built into things like fridges, freezers and air conditioners - the kind of temperature-dependent appliances that don’t require a constant, steady input of energy to function properly.

At present fridges, for instance, just shut down and restart intermittently, but under dynamic demand management the control box will be listening constantly to the hum of your fridge. It will understand that the lower the hum, the harder the grid is having to work - and thus choose this moment as the most efficient to shut down non-essential units. The thermostat will tell the box when these need to come back on. Spreading the load on the grid in this way, says Dynamic Demand’s director Joe Short, can raise the efficiency of Britain’s power production enough to cut carbon dioxide emissions by two million tonnes a year.

The technology recently got parliamentary backing, in a clause added to the climate change and sustainable energy bill. On course to become law in the summer, this will require the government to support research into dynamic demand control, and to report back within twelve months. Building in this technology will cost a few quid per appliance - not necessarily a huge hurdle, though it’s unclear whether the government would pick up the tab. But will the food remain safe? Tests under way at Intertek are assessing the performance of fridges and freezers under the new controls. The ice cream hasn’t melted yet. - Suzanne Fane Saunders

21 May 2006

Suzanne Fane-Saunders