What is a brownout and when can they be expected?

20Mar

A brownout is the reduction or restriction of availability of power in certain areas. In basic terms, this means reducing the power to household items such as lighting, appliances and equipment. For example, the lighting will be dimmed and appliances will run on less power than normal.

This doesn't mean that household electrical items will stop working, however knowing what a brownout is and why it's occurring can help to understand what is going on with home electrics at that time. Firstly, it is important to understand that it won't just be a household that is affected. Brownouts occur across areas, so it might only be certain streets that are affected, or it might involve a whole town or area. The overall effects of brownouts are yet to be decided, if at all.

Is a brownout expected in the UK?

It is now known when a brownout is expected in the UK, but it had been suggested that one was on the way last winter. A Liberum Capital analyst predicted a 10% chance of a brownout occurring last winter. Even with this prediction in place, there was still a 90% chance that the UK would not have one.

Why are the brownouts happening?

The cause of the brownouts would have been due to four EDF owned nuclear reactors that were shut down for safety reasons in August 2014. According to EDF, a crack was found on one of the boilers as part of a routine inspection, and a decision was made to shut the other 3 reactors down.

EDF stated that there should be a phased return to power between October and December 2014, however, according to an article in the Independent, it could be long into 2015 before the reactors are switched back on. The reactors produce around 4% of the UK's electricity.

The National Grid had expressed concern over the prospective shortages of power and was seeking emergency supply to cope with the winter months.

Will anything be affected?

There has been speculation that modern gadgets may malfunction or sustain damage from operating at lower voltages and may even burn out. There is no evidence documented to suggest that this is the case.

In reality, once electricity leaves the power plant, it forms a basic supply, and individual gadgets and appliances have built in transformers that convert the ordinary basic supply into the correct voltage. Therefore in simple terms, the voltage supplied by the energy company is not necessarily the voltage that is actually used in the home.

Some households in the UK have voltage optimisation units fitted in their homes where the supply of electricity in the home is more consistent to around 220V. This prevents the natural fluctuations of electricity which occur which can see supply vary to between 200-250V.

Based on these variables it would seem unlikely that household electrical items would be affected by the brownouts. However much of this would depend on how often the brownouts occur and how long for.