‘Smart’ appliances to ensure a smooth power supply

Ben Webster, Environment Editor An energy-saving trial that will shut down home appliances when peaks of demand threaten to overwhelm the network began this week.

About 300 homes in Sandwell in the West Midlands have received fridge-freezers that turn themselves off when the grid is overstretched. Altogether, 3,000 homes will take part in the two-year trial, run by npower.

Energy companies plan to offer grants and cheaper tariffs to encourage all households to switch to such appliances. If all homes had smart fridges, Britain’s annual emissions would fall by two million tonnes, the equivalent of taking 700,000 cars off the road or closing a large coal-fired power station.

The technology, which is known as “dynamic demand”, works by monitoring second-by-second changes to the frequency of the national grid. When the frequency drops below 50Hz, the system starts to switch off appliances and continues until the frequency returns to normal .

Some large industrial customers, such as steel works, already have contracts that allow the national grid to disconnect them at times of peak demand in return for cheaper energy bills. The Sandwell trial is extending the idea to domestic appliances and measuring how much carbon dioxide will be saved for each additional home that joins the scheme.

Npower said that customers would not notice the system working and would be in no danger of losing the contents of the fridges and freezers.

A spokesman said appliances would switch themselves back on if their temperature rose above the recommended level.

He said the same technology could be used to control the charging of electric cars, which will begin to be mass-produced by the end of this year and will become eligible from January for £5,000 government grants. The emissions savings from switching to electric cars will depend on how successful power companies are in managing the potentially huge increase in demand for electricity.

Electric car owners will be able to negotiate a cheaper tariff in return for allowing their energy company to control when their batteries are charged.

The driver will simply plug in and specify when the car will be needed. The grid will ensure that the battery is full at that time.

Paul Lazarevic, managing director of RLtec, which supplied the dynamic demand technology for the trial, said the grid could even draw power back from electric car batteries in order to respond to surges in demand.

However, he said more research was needed into what effect this would have on the life of the batteries.

The npower trial is being conducted under the Government’s Carbon Emissions Reduction Target scheme, which obliges power companies to reduce energy consumption in the home by promoting efficient technology.

Meanwhile, Sony has launched a smart television that automatically dims and reduces power consumption when viewers look away from the screen.

The Bravia LX900 has a camera that uses face recognition technology to detect when viewers are looking down to read a book or have fallen asleep.