Sunday 28 January 2024

Blitzbilanz 2023

Blitzbilanz 2023 (Quelle: abgerufen 28.1.2024)

Trotz schwerer Unwetter weniger Blitze

Blitze sind während eines Gewitters im Dezember 2023 über der Skyline von Frankfurt am Main zu sehen. - © dpa

2023 hat es viele Gewitter in Deutschland gegeben. Trotzdem wurden weniger Blitze als in anderen Jahren registriert.

2023 gab es zwar schwere Unwetter in Deutschland, doch war die Luft weniger elektrisch geladen als in vielen anderen Jahren. Insgesamt wurden bundesweit 316.000 Blitze registriert, die den Boden trafen. Das waren zwar 30 Prozent mehr als im Jahr 2022, aber weniger als in vielen anderen Jahren.

Orte mit den meisten Blitzeinschlägen pro Quadratkilometer.

Dabei gab es regionale Unterschiede. Bayern war das blitzreichste Bundesland. Die Messstellen registrierten dort über 70.000 Einschläge, mehr als ein Fünftel der gesamtdeutschen Zahl. Doch weil Bayern auch das größte Bundesland ist, liefern die absoluten Zahlen allein kein exaktes Bild.

Im längerfristigen Vergleich ist 2023 nicht sehr blitzreich gewesen. (Daten: Blids)

Trotzdem ist Süddeutschland ein Gebiet mit einer hohen Gewitteraktivität im Sommer. Das spiegelt sich auch in den Daten der Bitzedichte wieder, die unabhängig von der Größe eines Bundeslandes ist.

Tuesday 7 November 2023

Does the wind industry have a blade problem?

Since primary structural elements in wind turbine blades are designed with carbon fibre spar caps we face increasing damage scenarios by lightning impact.

Lightning can also have a big impact on the blade if there is carbon fibre built in primary load carrying structures like spar caps. Sometimes, lightning only leaves pinholes in the shell; sometimes, some lightning damage propagate to full blade failure if left unrepaired. Insurance companies in US report one-quarter to two-thirds of all wind farm-related claims involve lightning.*

* M.Malkin, A.Byrne, D.Griffin, Does the wind industry have a blade problem?, in: North American Wind Power

Semi-automatic linear motor driven sensor delivers focused signal

A phased array ultrasonic spar cap scanning device for uptower rope access is a cutting-edge technology that enables the inspection of spar caps (the primary load-carrying members) in wind turbines. This device allows technicians to conduct thorough and efficient inspections while suspended from ropes on the wind turbine tower. By using phased array ultrasonic technology, it can provide high-resolution imaging and accurate data on the condition of the spar caps, ensuring the structural integrity of the turbine.

This significantly enhances the safety and effectiveness of wind turbine maintenance and inspection and repair operations since uptower repair decision is obviously not only technological motivated but also a powerful business model and commercial cash cow.

Our focus is to invest in this non destructive technologies and gather experience for investigating the feasibility and reliability of a potential repair of the damaged areas in order to increase transparency of residual service life of retrofited blades. 

Sunday 5 March 2023

Let‘s go Odenwald

Again lightning stroke has been observed

Let’s go Odenwald! With a good friend on the set.
(im Bild: Uwe Scherbaum,

Ohhh, I never saw anyone crawling deeper!

Friday 18 December 2015

Martin Grabert our expert down under

Dr. Martin Grabert, Brisbane, Australia, now supports HMS Experts & Classification Society (HMS Sachverständige Berlin e.V.) down under. As a student of astronautics and aeronautics he was one of the first coworkers in the first Aircraft Design Company of West-Berlin, the innovative enterprise carrying the letters HMS in its corporate name, dedicated to develop a High Performance Powered Glider Airplane. I proudly present his cumulated professional experience in research support and collaboration activities.

Friday 22 May 2015

Production related weakness - how do you rate it?

HMS Experts in composite production technology Dr. Mertins and Dr. Holstein evaluating alignment of spar caps congruency to web suspension. What if waves and wrinkles weakens carbon girders? Can asymmetric load case trigger buckling? What if bonding lines of substructure between web and shell and of course at leading and trailing edge is of suboptimal adhesive performance? Can we trust flatback smooth curvature of LE UD reinforcement. Are international varying work behavior and cultural work related disciplin have influence on average blade production quality?

Sunday 1 February 2015

Non-OEM Major Blade Repairs

D-Check of two V44 blades

Wind turbine blade damages spread in terms of its severeness from a cosmetic minor to a major structural relevant level. Not often such fatal damages are beyond profitable reconstruction cost estimates. Original Equipment Manufacturer (OEM) usually play that game with joy selling supposed total losses to insurance companies who are regularly unable to cope. 

HMS "the expert's voice" networks intends to escort blade owners in order to perform major overhaul (heavy maintenance visit) such blade patients without OEM support but nevertheless show long-lasting service life. Independance is our credo enabling potential blade service companies in order to provide e.g. high level carbon fiber repair technology and/or LPS reconstruction. Customers position such turns out to be the winner of unproductive stand-off situation at the end of the day.

It is our focus to handle catastrophic damages, make classification of damage level and design repair measures. We make safe that repair concept, workmanship and performance of repair execution is provided within requested ambitious level. Such we approve the repair trough the power of 20 years independent experts experience and keep an eye on conformity and formal approval referring to certification standards.

Thursday 3 April 2014

It is rare, but never the less it is true

Just one year old - not having seen extreme conditions when it happend. Some claim, it is a joke of April 1st, I doubt it.

It looks more likely someone has pushed the over speed button too long...

Sunday 16 March 2014

Wellcome on board, Harald Schwarze, Varnish Expert first grade!

Harald Schwarze

HMS Sachverständige Berlin has strengthened its polymer wing of experienced old stagers. Harry has made his carreer all the way through from handicraftsman to member of the board of one of the leading Switzerland based paint manufacturers. He has accumulated profund experience in surface treatment in railways industries and gear box internal painting technology. The actual challenge in production supervision for off-shore rotorblades does entice Harry to break in on his hobbys like wave surfing and jazz drumming.

Wednesday 18 September 2013

Living blade experience

"Old fox meeting"

Wolfgang, Ove and Stefan (from left) have in sum more than 50 years of rotor blade experience! I am very grateful for such face-to-face encounter and is one of curiosity of life.

Saturday 16 March 2013

Personal Safety Training (Epoxy and Isocyanates)

Esbjerg, Dk, March 14 and 15, 2013
Most of the guys joining the classroom at AMU-Vest are pretty much familiar with the subject. In order to fulfill the regulations on the education program laid down by Danish law they all surrendered and so they were patient and hold out 2 full days. The "UDDANNELSESBEVIS CERTIFIKAT" was given for remuneration.

Tuesday 5 March 2013

Siemens blade production accessible via Internet

Siemens Wind Turbines are presented in a high level show case here

Friday 21 December 2012

It was my pleasure

Twentyeight years after this photo was taken, when the first wind turbine made by Ecotècnia was erected, where you can see (from left to right upright)
Josep Congost, Quim Corominas, Pep Prats, Pere Escorsa, Antoni Martínez, Ermen Llovet,
(and on their knees) Josep Puig, Miquel Cabré, Pere Viladomiu i Xavier Traver
Pep Prats and Miquel Cabré invited me to talk about blade strategy together with Richard A. Schmidt, Patricia Canalis, Alexis de Beaumont and Luca Feigl at Alstom Wind in Barcelona, Spain.
This is very honorfull for me, thank you.

Tuesday 27 November 2012

Reliability and Failure Analysis of Wind Power Plants

The international conference "Failure and Damage Analysis" is addressed to manufacturer of wind turbines, suppliers, service provider of operation and maintenance, energy provider, wind farm operator, consulting engineers, technical experts, financial institutions and insurances from all over the world.
Two days in March '13, on 20th and 21st, read more about the program here

Saturday 22 September 2012

Next Generation Unmanned Airborne Vehicles

Cassidian is the defence and security division of the EADS group and a major provider of global security solutions, lead system integration and aerial, land, naval and joint systems. Next generation of airborne military UAV or drones made me fall into evil mood. Visiting the ILA Berlin Air Show 2012 I had first time a feeling like being an engineer in astronautics and aeronautics is an embarrassment.

Never the less, civil use is measurable and we offer our expertise for damage analysis and root cause accessment for claim regulation purposes.

Monday 18 June 2012

After Sales Service Conference Frankfurt am Main

December 4th and 5th 2012 the 3rd German After Sales Service Conference supported amongst others by Bombardier Transportation, Lufthansa Technik, Bosch and MAN is held to learn from experience of others. Dr. Holstein's contribution is to give an insight in wind branch business processes and lessons learned with respect to off-shore restrictions.

Sunday 6 May 2012

Larger Rotors for low wind sites

Rune Schytt-Nielsen and Flemming Sörensen, Cofounders of SSP
"There is a strong trend towards larger rotors development in order to increase energy production and therefore decrease cost of energy production", Steen Broust Nielsen said when introducing today's challenges in blade design at the SSP site event on EWEA 2012 in Copenhagen. In the same time blade industrie will face an enormous price pressure due to very competetive environment in Asia Pacific.
Reliability concerns with longer blades will put an emphasis on suppliers and after sales service providers with clean records.
We at HMS feel very closed up to the SSP philosophy and have a similar approach to support the provision of blade quality through communication of approved service procedures, staff qualification and independant supervising services.
Feel free to get in touch with HMS Expert's Office, Berlin,

Sunday 4 March 2012

Damage class four incident (see also rotor blade damage classes)

Rotor blade maintenance and repair standards are to be correlated to structual blade condition and for repair decisions on basis of damage classes. This posting shows without any doubt a damage class four finding (total loss).

In this case there is hypothesis for fatal blade failure mode by carbon UD-girder  fiber damage due to transverse force stress induced by glass fiber helix winding technique in order to fix the UD-stack in semi-automated beam production process. This issue is discussed in preparation of next Technical Advisory Board Meeting of the AK R (a committee of the German Wind Association, see also

Less severe damages like cracks or delaminations have virtually two dimensions. The first dimension visible at a first glance is what we call inspection findings. The second and comprehensive dimension of a damage can be assessed after removing layer by layer of affected material. It is the difference about damage amount and it's range.

Thursday 16 February 2012

Interactive Knowledge Base on NDE of composites

In our every day analysis of failure modes and naming the root causes we recommend to standardize also well defined descriptions and in that sense definitions. Using the right classification for damage classes is one thing we often mention but also choosing the proper expression or definition for irregularities or findings is the other. We recommend the interactive knowledge base at netcomposites website. Http://
You will find 19 different failure modes of FRP material like "delamination" or "debonding" or "crack" and I find it very helpful.

Saturday 24 December 2011

Rotor Blade Quality Surveillance requested

Blade quality surveillance (BQS) is one of strongly requested support issues. BQS concept of an Offshore wind farm comprises a complete third party assessment of each key procedure to obtain Type and Project Certificate. It covers design assessment (second phase), blade testing and surveillance of important steps in project (IPE). In order to obtain and retain blade airworthiness periodic monitoring of blade production, witnessing of quality assurance inspections, testing and supervision of whole life cycle operation is mandatory as well as supervision of maintenance and repair acceptance procedures.