Which battery prevents grid congestion?

A battery can take power from the grid at times when the sun shines and the wind blows and there is overproduction of power. To relieve the grid at the right times, batteries must be able to be controlled. Emma Gerritse, energy system of the future consultant at Stedin, and Isabel Nowak, product and proposition manager at Stedin, explain how this control can best be organised and where the pitfalls are.

The main argument for using batteries to prevent grid congestion is their steerability. Steerability means that a battery responds the way you want it to, by providing the right incentive. If there is a surplus of solar power, the battery can capture the power by recharging. That way, the power does not have to be transported across the grid. In contrast, a battery should not start charging when a lot of power is already being demanded from the grid. For example, during peak hours in the evening, when everyone at home turns on the television, cooks and hangs the car on the charger.

Local grid congestion occurs when more power is generated or demanded than the grid can handle. As a symptom of this, lights may flash or appliances may fail. If a lot of solar power is generated, it can also lead to voltage problems. If there is too much voltage on the grid, it causes inverters to fail.

What are congestion relievers?

Congestion relievers can contribute to reducing grid congestion by matching their power consumption to peak times. For this, they receive compensation and priority on the waiting list for transmission capacity. The conditions for qualifying as congestion reliever are laid down in by the grid operators.

There are six criteria that must be met to be seen as congestion mitigators:

• Users must be on the waiting list and be able to contribute to reducing congestion.
• The user should not increase congestion at other times or in other areas
• The user must reduce the congestion peak by at least 1,000 kilowatts, for direct connections to the high-voltage grid it is 10,000 kilowatts.
• Users can reduce congestion by deploying transmission capacity in the opposite direction (offtake or feed-in).
• User can reduce consumption during moments of congestion
• For areas where TenneT also has or expects congestion on the high-voltage grid, TenneT will also have to agree to the application.

When a user meets these conditions, it is granted a congestion management contract. This gives a user priority on the waiting list for transmission capacity and compensation for reducing grid congestion.

Source: solar365.co.uk