The pursuit for innovation is a never-ending quest across the Danish wind industry. To test the feasibility of ideas and the durability of new solutions, companies go through exhaustive testing. The aim is to come up with a solution that is better than the previous, while at the same time lowering production costs and ensuring consumers receive a competitive price on electricity produced from wind turbines whether they are installed onshore or offshore. By testing each component in the wind turbine vigorously and by testing prototype wind turbines in part and full-scale, potential design or production errors can be identified, and corrected before the final product is delivered to the customer.

Identifying and eliminating design and production errors in the early testing phases is much cheaper than having to correct them after the turbines have been mass-produced and installed in markets across the world. Having access to the right test facilities thus helps reduce the levelised cost of energy (LCOE) for wind.

A visual testament to the Danish wind industry’s abilities can be found in the rural area of Østerild where seven large test turbines are installed. Østerild is currently the only place in the world where measurements can be made on turbines of up to 250m in height.

Further south, on the island of Funen, wind turbine manufacturers can test nacelles, simulating a full lifetime of operating in shifting and rough conditions at the Lindoe Offshore Renewables Center (LORC).

Research record

Denmark’s extensive knowledge of wind energy has attracted influential players from the international wind industry to the country. Among them are Chinese manufacturers such as Envision Energy and Goldwind, who have both opened research and development divisions in Denmark. Envision Energy is also present at Østerild along with GE-Alstom and the Danish manufacturers Siemens Wind Power, Vestas Wind Systems, and MHI Vestas Offshore Wind.

Danish technical universities have a longer track record of working in wind energy research than universities in other countries. In the late 1970s, when an emerging industry started producing turbines, a test facility for wind turbines was established at the Risoe National Laboratory, now DTU Wind Energy.

The Danish Government assigned Risoe to approve turbine prototype designs before they could be sold to the Danish market. This was an early example of close cooperation between the universities and the industry on testing and improving designs and research programmes. The universities and the industry continue to cooperate today, each benefitting from the other’s competences and resources. The Danish research environment has expanded in parallel with the wind industry. Although strong research environments are developing in other countries, Danish institutions remain among the best in the world.

Test scheme

Global wind market players continuously seek to develop test projects that can potentially reduce production costs of electricity and keep offshore wind energy costs competitive. In July 2015, the Danish Energy Agency published a call for applications for tests of new technologies to establish and operate wind energy production offshore. Turbines in the test scheme receive a ‘contract for difference’ of approximately €0.09/kWh (DKK 0.7/kWh) for about 11 years and then market price until decommissioning. Based on minimum criteria, such as technical and financial capacity to ensure a potential for development, and the commercial perspective of the test elements, the scheme was granted to I/S Nissum Bredning Vind for their 28MW test project in February 2016. The project’s main elements are a Siemens Wind Power 7MW wind turbine; a new Siemens-designed concept consisting of gravity jacket foundation and concrete transition piece; a slender tower concept; 66kV cables; and a switch-gear solution.

The largest turbines are designed for a life offshore. However, testing of offshore turbines often has to take place onshore and there is no better place to do this than a location with relentless, rough winds. The world’s biggest test centre for large wind turbines is located in Østerild, Denmark. The test centre has room for seven turbines with a maximum height of 250m and a capacity of 16MW. Today, the rural area is home to prototype wind turbines from manufacturers around the world. In close collaboration with wind turbine manufacturers is the Technical University of Denmark (DTU), which leads research at Østerild. At the same time, DTU shares the story of wind energy with 50,000 visitors who make their way to the impressive test centre each year. In coming years, the test centre will be expanded to be able to test even taller wind turbines before they are installed offshore.

Extremes of nature

The employees at LORC are experts in matching broad knowledge of offshore wind with deep knowledge of how to get the most out of LORC’s full-scale test facilities. At the centre, the customers are the experts on their own assets. Partners and outside experts are brought in with different focus areas to supplement test scenarios.

The Function Test Facility is used to verify the performance and robustness of the nacelles’ electrical systems as well as grid compliance when exposed to the extremes of nature in a controlled test environment. It is equipped with a 13MW direct-drive motor providing more than 12MNm of torque that allows testing of nacelles in the 10MW range. Additionally, other full-scale test facilities can perform highly accelerated lifetime tests or climatic testing, where the harsh environment offshore can be simulated by means of temperature, humidity and salt spray.

Capturing energy

It is envisioned that offshore wind energy will play a significant role in the delivery of clean, renewable energy in the future and the cost is constantly being reduced. Offshore wind projects coming online today are already delivering power at almost half the price of projects completed in 2012. This is due to increased competition, and larger turbines and components. A good example is the 88.4m blade for offshore application that was introduced by LM Wind Power in June 2016.

The giant blade is based on a newly developed carbon-glass hybrid technology, and has been built and tested to last for 25 years offshore in the harshest weather conditions and roughest seas. One wind turbine with 88.4m blades can generate enough electricity to power 10,000 European homes.

This article was taken from ‘Wind Energy Moving Ahead: How wind energy has changed the Danish energy system’. See

Key points for a strong testing environment

  • State-of-the-art test facilities that are privately and publicly funded.
  • World-leading wind energy research institutions.
  • Access to highly educated wind energy personnel.
  • A large group of experienced R&D professionals in the industry.
  • Short distance between test sites and companies’ R&D divisions.