Load Shedding Explained

Load shedding describes what happens when a power station can’t produce enough electricity. When this happens, it stops supplying electricity to certain parts of the grid to ‘shed the load,’ and relieve pressure on the power plant.

There are lots of reasons why load shedding happens, and there are a number of consequences for customers. Understanding why load shedding happens, and its impact on energy users and grid operators, can help to identify solutions that ensure uninterrupted energy supply in the future.

• What is load shedding?
• How does load shedding work?
• What are the impacts of load shedding?
• How can load shedding be avoided?
  

What is Load Shedding?

Load shedding is when a power station cannot meet demand for electricity, power is switched off to parts of the grid to protect power generating assets.

Some of the reasons load shedding happens include:

• • population density leading to increased power demand, outstripping local power capacity
  • an unexpected failure of a major electricity generating asset
  • extreme weather events causing a sudden surge in electricity demand
  • damage to transmission lines or other network equipment during severe storms or earthquakes
    
  
  

Where load shedding is used, it’s a last-resort measure to keep a continuous power supply running to some parts of the grid. It also protects the electricity network from damage that could cause long-term interruption to power supply.

How does Load Shedding Work?

Load shedding is used to balance the demand and supply of electricity across national electricity markets. Electricity Market operators, who are responsible for maintaining the reliability and safety of the grid, make the decision to begin load shedding when there is a significant or dangerous imbalance between electricity supply and demand.

Load shedding is commonplace in some countries, like South Africa. In Europe, the practice is less routine, though countries including Spain and France have signalled that there may be the need for regular scheduled power cuts (also called rolling blackouts) this winter when it is anticipated that there won’t be enough power being supplied to their national electricity suppliers to meet demand.

Most countries have a national strategy to deal with imbalances in power networks, with a rigorous procedure of steps for distribution network operators to follow. This is usually designed in close collaboration with national governments.

 Across the European Union, member states have emergency response plans that outline the steps to take to deal with gas and electricity shortages. Countries with different stages of emergency response actions, like Belgium for example, even have assessments that take into account the fairness of their load shedding plans on customers. 

In many countries, load shedding is categorised in stages, by severity and the significance of the gap between a country’s electricity generating capacity and customer demand. Stage 1 is considered the least serious and stage 8 is the most severe. Load shedding outages usually last for a few hours at a time.

When power outages are required during a load shed event, customers are grouped together into clusters and their power supply is limited by the operator. Power in the group’s electricity conductors is turned off and on intermittently to homes and businesses, unit the network is stabilised.

Typically, the outages are rotated on a schedule from group to group until the load shedding is complete and there is enough power available to meet demand. As one group’s power outage ends, the load shedding moves to the next group, and the first then regains their normal electricity service. This helps to minimise the effect of limited power on customers.

The groups are decided by the amount of power that needs to be shed at the time the outages happen, and can vary dramatically depending on the severity of the imbalance between supply and demand. In some instances, a manual circuit breaker process is needed to return power to customers at the end of a load shedding event. This can take longer than the automatic process, which can lead to greater disruption for customers.

Safety is a key concern for grid operators when deciding where and when load shedding occurs. In most cases, they try to avoid limiting power to critical customers like hospitals and safety services, and buildings like police departments and water systems.

What are the Impacts of Load Shedding?

The most obvious and cumbersome impact of load shedding is for customers, who face continued interruption to their electricity service. In countries with emerging economies and insecure network infrastructure, such as South Africa, household, social and economic activity can be severely limited by load shedding.

Where load shedding is common practice, customers have advance warning of when power will be unavailable in their neighbourhood due to load shedding. For individuals, a loss of power supply is at best frustrating and at worst inconvenient and costly.

In regions where there is advance notice with scheduled outages, customers must plan ahead to make sure they have access to cash, transport, food, and medication. During outages, ATMs, petrol pumps, gas stoves and refrigerators do not work, so customers need to ensure they have adequate supplies stocked up in preparation.

Load shedding can also damage devices or lead to lost data if they remain plugged in when power is switched on and off. For businesses, outages can force them to close or pause their operations, which can lead to lost productivity and loss of profits.

In developed economies, investment in mature grid networks and infrastructure has largely shielded them from relying on load shedding. However, new challenges on the horizon for the world’s energy sector have seen the re-emergence of discussions of load shedding in nations like the US and UK.

How can Load Shedding be Avoided?

On a household level, energy customers can look to avoid power outages from load shedding by converting to solar power or purchasing a generator. The advantages of having such a system in place, for when load shedding does occur, far outweigh the cost.

On a macroeconomic level, ensuring the continued security of electricity requires robust governance, energy policies and procedures. The global energy economy faces some sizable challenges because of climate change, and the clean energy transition that make load shedding more likely without proper planning and governance.

The fundamentals of generation, transmission, and distribution need to be taken into consideration by electricity network operators to avoid having to resort to load shedding.

One of these measures is increased flexibility services, like demand response. Demand response is when customers change their electricity consumption to help keep the supply and demand of electricity in balance. This increases flexibility in the grid and helps ensure uninterrupted service. 

Through demand response measures, consumers are given a signal to decrease or increase their energy usage to restore balance to the grid when there is a change in supply and demand.

Demand response lowers the likelihood of unplanned power outages. Offering flexibility within energy assets helps ensure that grid frequency can be maintained and avoid these major problems that lead to load shedding.

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Sympower is dedicated to creating a fully renewable energy system. We are the energy experts with years of experience in demand response and flexibility optimisation. Our goal is to turn the potential of your energy assets into extra revenue for you. We provide the technical expertise, all while you stay in control.