3.5. Grid losses in our control areas

G4-EU12

ELIA IN BELGIUM

When electricity is transported, part of the energy is converted into heat, and is known as ‘grid loss’. Grid assets such as overhead lines, underground cables, transformers, etc. all have a small amount of electrical resistance which causes them to heat up as soon as an electric current flows through them. Grid losses are therefore the difference between the amount of electricity entering the grid and the amount of electricity supplied. They are unavoidable when transmitting electricity and depend on the voltage of electricity and length of the transmission lines, amongst other factors. The high-voltage direct current (HVDC) technology used in some of the interconnectors is more suitable than conventional three-phase alternating current technology for transmitting large quantities of electricity with low grid losses and optimal control over long distances.

When assessing the carbon footprint of a TSO in line with the Greenhouse Gas Protocol, grid losses-related GHG emissions are accounted for in its indirect GHG emissions (Scope 2).

The energy mix generated and fed into our system determines our carbon footprint. A high integration of renewable energy translates into limited GHG emissions.

The reduction of grid losses is not the only factor that should be considered when developing our grid, since too narrow a focus can lead to adverse effects and even slow down the integration of renewable energy.

For further details on the group Carbon footprint, see Section 8.2.1. Emissions – Greenhouse Gas Emissions. In Belgium, there is a distinction between two categories of grid losses:

• Grid losses monitored at federal level (≥ 150 kV) compensated with kind in accordance with federal legislation;

• Grid losses monitored at regional level (< 150 kV) In 2021, the grid losses of Elia Transmission Belgium SA/NV totalled 1.5 TWh. Its transmission losses expressed as a percentage of total energy (electricity transmitted) were: 2.03%.

Grid losses

Federal level (from 150 kV)

Regional level (less than 150 kV)

Grid losses total

unit 2019 2020 2021

MWh 788,191 717,811 918,071

MWh 547,383 539,061 558,922

MWh 1,335,574 1,256,872 1,476,993

The losses are calculated using the Energy Management Systems (EMS) State Estimator. The EMS models the entire Belgian network, listing each network element. The State Estimator will estimate the state of each network element on the basis of measurements taken in real time and the system modelling parameters.

50HERTZ IN GERMANY

In 2021, the grid losses of 50Hertz Transmission GmbH totalled 2.4 TWh. Its transmission losses expressed as a percentage of total energy (electricity transmitted) were: 2.17%.

50Hertz Transmission GmbH has already planned the SouthEast Link between Saxony-Anhalt and Bavaria, the first 525 kV HVDC transmission line in its grid area. As mentioned above this technology is more suitable than conventional three-phase alternating current technology for transmitting large quantities of electricity with low grid losses and optimal control over long distances.

To be able to better predict the amount of losses and purchase electricity for balancing out the grid more cost-effectively via the electricity market, 50Hertz Transmission GmbH has developed a new forecasting model based on artificial intelligence (AI). It developed the grid loss model in cooperation with the Fraunhofer Institute for Optronics, Systems Engineering and Image Analysis (IOSB) in Ilmenau.