Is Load shedding the solution?

When the electric grid is under strain, many electric utilities use the load shedding technique to lower demand and balance it with energy production.

The idea is to turn off the power supply to certain areas on a cyclical basis, for example, two hours ON, then two hours OFF. The local utility releases this timetable in public media. I’ve personally encountered it in several of countries. To stay open, shopping centers employ diesel generators or there are private energy storage devices in use. These measures are having a significant effect on residential and commercial energy consumers.

The utilities involved have undoubtedly taken all necessary steps to improve their capacity for producing electricity; therefore, expanding another power plant won’t work. Many temporary solutions to handle a peak load include energy storage in batteries or pumping water into an upper lake for later usage using a turbine during overproduction.

Often, inadequate utility long-term demand projection requires load-shedding to avoid a large-scale black-out. There are other factors too, e.g. Pakistan typically has a daily power outage of roughly 8 hours in urban regions and about 10 hours in rural areas due to load shedding. The actual power gap now exceeds 8GW. The main causes include a lack of fuel for diesel power plants, technical difficulties, and low water levels at the dams where hydropower is produced.

This year (2022), France has been struggling with a lack of cooling water for its nuclear power facilities due to an extremely dry period. Some situations are difficult to predict. Load shedding has a remarkable history in South Africa. For around 15 years, there are recurring total area disconnections. This is due to the state-owned electricity provider, Eskom, failing to keep up with the speed of economic development.

The South African utility built 14 new power plants between 1961 and 1991. Since then, Eskom has completed the build of three of the 14 power stations in the 32 years that have followed. The situation is improving with the new Eskom management.

In general, the load-shedding strategy is outdated. The shedding is carried out based on previous demand levels. As a result, there is a great deal of doubt about the actual energy demand. It is impossible to accurately balance power generation with a whole region. Therefore, there should always be more power generated than is needed to prevent a total blackout.

How to overcome load-shedding with smart meters

Data acquisition

Utilities are often forced to implement load shedding due to the lack of accurate information about the customer’s energy usage. A more accurate forecast of demand can be made by the utility when it possesses customer- and regional load profiles as well as meteorological information such as local wind speed and sunshine duration. Using an AMI system is necessary for data collection. With enough data, a 15 minutes forecast can be made with high precision.

Customer Education by Billing

Utilities have several instructional approaches to shift usage away from peak-load hours, with tariff structures linked to the retrieved data and invoicing based on maximum demand.

Programmed Load Limiting

Every smart meter has an integrated relay that can be used for many purposes. The customer load can also be limited by using this relay. The meter disconnects a specific consumer if the load exceeds a programmable threshold, but all other customers continue to have electricity. Once the consumer has decreased the load, a specific algorithm is used to restore the power. The load limit is programmable by the AMI system and can be set in the energy meter. Reprogramming requires some time, therefore it is useless in case of emergency. The real usage is to balance the predicted available power to all consumers at all times equally. Another aspect is the countries’ social responsibility.

Flexible Load Limiting

The crucial value to predict an impending power shortfall is the net frequency. To maintain frequency stability, it is possible to establish the load limit internally using a linear- or progressive function with electronic energy meters that can be programmed. In this manner, a portion of the system stability is taken care of by each smart meter, and all customers receive power. This makes the meter incredibly smart.
To implement this functionality, you’ll need to be able to identify the correct load/frequency relation formula. The AMI system can be used to retrieve the relevant fundamental data. We use theoretical models for evaluation, no customer has ever requested it.

Restoring the Power Supply after Outage

Huge inrush currents occur after the electricity is restored to a certain area. The protection against this is lacking in electromechanical energy meters. As a result, household appliances age prematurely or sustain damage. Once electronic meters are installed in the field, there are other possibilities. For a sequential energising or the end-customer, for example, within a minute of the power being restored, we have solutions. This makes the network more reliable by lowering the inrush on the generator side.

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Takeaway

Load shedding is a problem, not a solution. It might be temporarily necessary due to extreme weather conditions or the lag of fossil fuels. The long-term strategy must be to enlarge the capacity for power generation, together with energy storage during times of overproduction. For specific questions, get in touch with us.