What are blackouts and why might they happen this winter?

National Grid has warned that there could be blackouts this winter if gas power plants are not able to keep running due to the energy crisis.

The electricity systems operator said it is still unlikely but winter could see the first planned blackouts, which the grid calls rota load shedding, since the 1970s.

But why might blackouts happen this year – who will be impacted and what can be done to avoid them?

Why would a grid ever plan blackouts?

Engineers working on the energy grid need to make sure it is “balanced” at all times.

This means that the amount of electricity being put into the grid by power plants, wind farms and others should match the amount being taken out by households and businesses at any given time.

The grid plans for when it thinks demand can be high so it can ask generators to meet that demand.

But if there is ever an imbalance where demand is higher than supply or supply is higher than demand, it can cause major breakdowns in the grid.

That could cause actual physical damage to the grid that could take days to repair.

If the engineers know there will not be enough supply to match demand, sometimes they need to reduce demand by planned outages to avoid major damage.

Why might blackouts be necessary this winter?

Britain has one of the most reliable power networks in the world and unless cables are cut by storms or other accidents outages are rare.

But this winter, gas generators might not be able to get enough gas to keep running.

The grid said that if this happens, it still thinks that is “unlikely”, then it might have to cut power to some households and businesses.

Who will be impacted by blackouts and who gets cut off first?

If the grid realises that it has to cut off some parts of the country, it will issue a warning to the local and regional distributors saying how much demand needs to be cut.

It will be up to these so-called distribution network operators to decide who gets cut off and who does not.

But the DNOs have limited controls so most of the time it will be whole areas that are impacted.

How can we avoid blackouts?

If the blackouts are caused by a lack of supply, then the only way is to reduce demand at particular times.

Most demand happens during peak hours of between around 4pm and 7pm when people get home from work, put the kettle on, switch on their ovens and sit down to watch TV.

The overall amount of electricity that people use does not have to reduce if they just change their usage to other times of the day.

For instance, electric cars could be unplugged during these hours, switching the dishwasher could wait until 9pm and you could put the washing machine on earlier in the day or during the weekend.

The grid and energy suppliers will launch a new system in November to pay people if they change the time that they use energy.

The Government could also step in to ration peoples’ energy use or advise them to use less, similar to a hosepipe ban, but so far it has ruled this out.