Learn about the current state of wind power in Europe (Part 2)

"WindEurope TECHNOLOGY WORKSHOP 2021" Participation Report

European wind power stakeholders gathered at the "WindEurope TECHNOLOGY WORKSHOP 2021What topics were discussed, and what are the challenges facing Japan compared to Europe? This is the second part of a report from members of Relatec who participated in the workshop.(Click here for the first part)

Challenges of large-scale wind farms

Misaki　I got the impression that there was a lot of talk about wakes and blockages in this workshop. About half of the participating rooms were focusing on these two topics. Wakes have been studied for about the last 2 years, but blockages are a more recent topic.

Wake	Air flow on the lee side of a wind turbine when generating power. Compared to the area in front of the turbine, wind speeds are generally slower and there is more turbulence.
Blockage	A phenomenon in which wind speed decreases upstream of a wind turbine when generating electricity. It has been shown that in offshore wind farms, this effect is greater than the sum of the effects of individual wind turbines.

In Europe, there have been reported cases where blockages occurred when large-scale offshore wind farms were constructed, reducing wind speeds and resulting in less than expected power generation from the entire wind farm.

As a result, there were lively presentations and discussions on methods for accurately modeling and simulating wakes and blockages.

Konagaya　When I attended the conference 4 or 5 years ago, the blockage phenomenon had only been reported. This time, however, research had progressed to the point of predictive simulation and verification of its accuracy, which left a strong impression on me. I think this will likely become a field that will continue to be researched.

--This research is possible only in Europe, where large-scale wind farms are in practical use.

Konagaya　In Japan, there are no offshore wind farms in operation yet, so there is not much research on this topic. Research on wind farms has begun in Japan, but to verify the accuracy of the results of simulation predictions, we still need actual wind turbines. I think Japan still has a long way to go in this field.

Accurately measuring wind speed with nacelle lidar

--Were there any other presentations that made an impression on you?

Konagaya　This was a research presentation on a wind survey using a nacelle lidar. A nacelle lidar is a small lidar that can be mounted on the nacelle of a wind turbine (the facility that houses the generator, control device, etc. at the top of the tower) for observation.

Nacelle Rider A nacelle is the long, horizontally shaped cylindrical part on a wind turbine tower that supports the rotation of the blades. Also called a nacelle-mounted lidar, this is a small observation lidar that can be installed on top of the nacelle.

In the presentation, a nacelle lidar was used to measure the wind turbine's facing direction relative to the wind and the wind speed in front of the turbine. This type of measurement check is necessary before the turbine is built to verify whether it is able to generate the power expected.

Until now, measurements have been taken using an anemometer installed on the wind turbine, but the wind measured there is affected by the rotating blades, so the value is not accurate.

Nacelle LIDAR can shoot a beam ahead of the blades to capture the wind in front of the turbine, allowing for more accurate measurement of wind conditions that are closer to reality.

Nacelle riders have not yet been widely adopted in Japan, but at Relatec we were hoping to test their effectiveness in the near future, and in that sense the research presentation on Nacelle riders was very helpful.

Lack of measured data on offshore wind conditions: an issue facing the Japanese domestic market

--What challenges have you seen for Japan this time?

(I.e.　By participating in this workshop, I was reminded of the difference in market maturity in offshore wind power generation. In Europe, where practical application is progressing rapidly, actual measurement data and experience are accumulated. In other words, development is also progressing more easily.

There is a wealth of publicly available observational data in Europe. Germany, one of the countries that has been successful in offshore wind power, began observing wind conditions using offshore masts around the 2000s. Moreover, this data is made public for research purposes, and can be used not only by people in Germany, but also by Japanese people like us if we follow a certain process.

In Europe, where observations began early and research and development has been carried out by making data public, I think the hurdles to practical application were low.

On the other hand, in Japan, there is almost no such observation data available to the public. This is a big problem. No matter how much European technology we introduce, if we cannot verify how it will work in Japanese seas, development will not progress.

Currently, Relatec is working with Kobe University on a NEDO project related to offshore wind survey methods, but a major issue is the lack of publicly available observation data. We must now seek a solution.

Japan's offshore wind power industry is finally taking its first steps towards Europe, roughly 20 years behind the rest.

Misaki　Of course, this is an issue for the entire industry. I want to create a system where various parties, such as the government, local governments, and companies, can work together to provide data, which will lead to the spread of wind power generation. I would like to consider what we can do as Relatec to achieve this.

I hope that one day we can improve Asia's offshore wind power technology.

Konagaya　The workshop also featured a power generation forecasting competition, a periodic event in which participants compete to predict the power generation of operating wind farms.

There are actual measurements of wind conditions and power generation, and the competitors hide these values ​​and compete to see who can get closest to those values. In other words, it's a competition of simulation technology.

Misaki　Since the prediction methods are different, we can examine and consider which one to use and what kind of results will come out. By clarifying the uncertainties of each method, we can improve our technology.

- Is Relatec considering participating in the future?

Misaki　That's right. It would be interesting to test how accurate our predictions are in an environment like this.

Konagaya　Currently, most of these power generation forecast competitions are held only in Europe, so I would like to see them held in Asia as well. Taiwan is ahead of Japan in the introduction of offshore wind farms.

I believe that if Asian countries can exchange information and increase their mutual knowledge through events like this, we may be able to promote offshore wind power not only in Japan but throughout Asia.

(Written by Izumi Kanchiku, edited by Hisae Sasaki)