Netherlands: ECN wind study strengthens the Borssele wind farm business case

The Government has commenced a public procurement procedure for two of the four plots in the Borssele wind energy zone. Various project developers have been working on a proposal for these offshore wind farms ever since. One of the tender requirements is to include a wind study conducted by an independent, expert third party, such as ECN.

Accurate foundation for business cases

“These are substantial projects that will have a significant financial impact. Each plot requires an investment of more than a billion euros. If the wind yield is one per cent lower, this could save tens of millions of euros over the project period. An accurate calculation is therefore essential,” explains Bernard Bulder, coordinator of wind studies at ECN.

Many factors play a role in calculating the yield: How will the park be set up, what sort of turbines will be used and where will they be placed in relation to each other? And at the next level of detail: what is the nominal capacity, the shaft height, the rotor diameter and the water depth? Bulder says: “We use the commissioning party's design as a starting point. Then we add wind conditions that we have determined on the basis of ECN's validated data and long-term KNMI predictions. Subsequently, we use an advanced computer model – developed and extensively validated by ECN – to calculate the expected wind yield. We will also model the impact of previously constructed wind farms on the Belgian coast. A great advantage of our model is that it has proven greater accuracy and is different to the tools that the developers use themselves. It therefore is a proper second opinion.”

Highly confidential

According to business developer Piet Warnaar, the three factors of greatest importance for developers are: the amount of investment, the operating and management costs over the life of the wind farm, and most of all wind yield. ”These three factors determine to a large extent the outcome of the business case and the bid that our commissioning party will submit in this tender. Naturally, what we know about who is participating and the results of the studies is highly confidential because commercial bids are involved. In fact, confidentiality is so important to ECN that we have separate teams for different commissioning parties and keep our work for them physically separate.”

Two plots left in Borssele

The procurement procedure for the first two plots at Borssele for 350 megawatts each is now in full swing. The tender for Borssele 3 and 4 will follow in August 2016. Warnaar says: “We are ready to carry out more independent wind studies for project developers. Since we have all of the required knowledge, we can provide a complete wind study within three weeks. Moreover, we are directly involved with all wind measurements in the area and have reliable, long-term historical wind data on the entire Dutch part of the North Sea. With our validated tools, we can guarantee developers and investors a high degree of accuracy.”