Turbine towers can be up to 150 metres tall and the blades can be as long as 91 metres, so how do the laboratories test the blades and who makes sure that the testers are doing their job correctly?
Over the past decade, international standards and requirements for measurement procedures for wind velocity and wind turbine generator systems have been developed and continue to be developed. This meant that for certain measurements, several different procedures for gathering and assessing the data existed and led to different measurement results. These results were not comparable even if the testing facilities followed the same recommendations.
IECRE, the IEC System for Certification to Standards Relating to Equipment for Use in Renewable Energy Applications, offers testing and certification which reassures investors, manufacturers and users of RE technologies that these are safe, secure, interoperable and function correctly wherever they are in the world. The system covers the wind, solar photovoltaic and marine energy sectors.
One of the tasks of IECRE approved test laboratories is to facilitate harmonized interpretations of testing requirements to enable global acceptance of test results through proficiency testing.
e-tech spoke with Alejandro Martínez Muelas, who is the Convenor of the RE Management Committee (REMC) Task Force 3 RETL proficiency testing within IECRE, to find out more about the proficiency testing process. Martínez works at the calibration laboratory for anemometers at Madrid Polytechnic University.
How does a laboratory become IECRE approved?
For a lab to become part of IECRE, it must successfully participate in proficiency tests. These include:
The anemometer calibrations can be tested in the laboratories. The device is roughly the size of a shoebox, so we send it to the different labs to do the tests. Then we compare all the results we get from each lab.
The first tests were done in 2016. This year the second round of the four proficiency tests will happen after summer.
Two new proficiency tests
Some laboratories would like to become approved to operate within IECRE, but they need to be able to perform certain measurement tests for wind turbines, which have not previously been available.
Starting in mid-June, we will offer the following two new tests:
We have listened to industry and what it needs and we’re really excited to offer these new and important proficiency tests.
How do you ensure a fair process?
We ensure fairness throughout the process by choosing a provider to do the administration, register participating test labs, collect participant fees, run events, make sure all participants get the data, and receive the group results at the same time, assuring a fair evaluation. Measnet, a cooperation of laboratories from the wind energy sector, will carry out the next set of tests.
IECRE and the provider choose a so-called conductor who checks the databases are correct and that all participants understand the different database fields. Participants then undertake their own evaluations and report their results to the conductor. Then the conductor evaluates the performance of all the participants and is the technical person responsible for the proficiency test.
What are some of the challenges?
One problem is when a standard may include different methods to undertake the testing. This means different labs may get different results because they do not all use the same methodology or have the same interpretation of the measurement criteria.
For this reason, we do two rounds. The first time the labs can choose which method to follow. Then we meet and check the results and find the differences. If this difference is because the standard is wrong or it is not clear, we fill out a clarification sheet, which explains what we found and notes the clarification agreed by all participants and that it should be corrected and amended.
Another alternative is to say that there are two options in the standard, both are correct, but to get the most harmonized results among the laboratories, they must all use the same testing option and specify which one.
What happens after the testing?
To ensure industry transparency, the labs which pass the proficiency test are published on the IECRE webpage.
Additionally, reports are published which explain the basics of what has been done (which test or method which labs participated passed and the key points.
Find out more about IECRE proficiency testing