News item | 2015-01-23 | 10:38 AM

How Dutch wind power will stabilise the grid

The stability of electricity grids has declined in recent years due to the large-scale introduction of renewables. Vattenfall/Nuon is the first energy company on the Dutch market to offer a new service from a wind farm that will stabilise the grid.

Vattenfall/Nuon has finalised a deal with TenneT, the Dutch high-voltage grid operator, who will consequently produce reactive power from the Princess Alexia wind farm.

Reactive power is needed to control the voltage and secure the long-distance transfer capacity of the grid. Not all wind farms are built to produce reactive power, but they can do so with some adjustments.

"A small investment must be made for the modifications, and the power losses increase slightly. However, these factors are effectively compensated by the extra revenue we get from selling the reactive power," says Peter Buskermolen, Power Origination manager at Asset Optimisation and Trading.

More flexible wind farms

Vattenfall/Nuon is the first energy company in the country to offer this service. But Buskermolen believes the business will grow in the future.

A stable grid requires minimum fluctuations in frequency and voltage. In the Netherlands, it is becoming increasingly difficult for grid operators to keep the voltage within its bandwidth. One reason is the rapid introduction of renewables. So far, Dutch wind farms have not offered the flexible, stabilising abilities of conventionally fired plants. But this is about to change.

"In the future, I would like to see all new turbines equipped in this way. Demand for this service will rise, and farms that provide it will increase their revenue by approximately one percent. We need wind power to become a more flexible energy source. And a wind farm can produce reactive power even when its windless," says Peter Buskermolen.

Denmark requires all generating units connected to the main grid to be capable of producing reactive power, but this is only called upon in emergencies. Swedish wind farms do not have a reactive power requirement. German wind farms do face similar requirements to those in Denmark.

A new EU directive which will require all wind farms to produce reactive power is being planned.

In an upcoming article, Vattenfall News will investigate how wind power also can contribute to improving the quality of the grid frequency while becoming more profitable at the same time.

Facts about Princess Alexia Wind Farm

The Princess Alexia Wind Farm was inaugurated in 2013 and consists of 36 turbines with a total installed capacity of 122 MW. It was Vattenfall's largest onshore wind farm at that time. It is named after Princess Alexia of the Netherlands, who was born in 2005 and is second in line of succession to the Dutch throne.