hwstowers@hwstowers.com | +34 943 598 469

HWS | San Sebastian · SPAIN

| +34 943 598 469

HWS | San Sebastian · SPAIN

«HWS has developed an universal Concrete-tower ANCHORAGE-System Concept, for installation of wind turbines using self-climbing cranes»

This disruptive anchoring system, enables to all the brand new self-erecting cranes to climb any of the existing concrete towers in the market.

A. Description of the anchorage system

The patented anchorage consists of: 

          (1) In the CONCRETE TOWER: Some CAVITIES (or HOLES) with a special shape that are left in the tower wall and are protected by some METAL FRAME (inserted on the concrete, orange in the picture). These inserts are economic and easy to attach to the mold and embed during manufacturing of the prefabricated tower segments, without practically altering and making the tower more expensive. The openings in the wall can be through or  non-through and take the form of a hole or niche.

          (2) In the CRANE: Special metal ‘SPIKES’ (in green in the picture) that get correctly locked in the metal inserts in order to anchor the self-climbing crane to the tower. These SPIKES are barrel-shaped steel elements with rotary motion and some end plates located at the front and rear ends of the piece.

In a hooking position the SPIKES are inserted into some of the tower CAVITIES, in such a way that the lower part of the spike is in contact with the inside of the hollow body of its corresponding metal insert, transmitting the weight of the self-climbing structure to the tower, and being held in position by that weight.

Meanwhile, the end plates are engaged against the peripheral end surfaces of the metal inserts, blocking the horizontal displacement (f.i. caused by wind loading), and therefore avoiding that can be released.

Both the metal inserts and the interlocking spikes can be distributed one by one or in groups, although in pairs is preferred.

B. Advantages of the invention

The special shape of the presented anchorage system provides several advantages:

          During INSERTION of the spikes:Its special shape allows for a smooth and guided insertion of the spike into the cavity. In addition, the rotary motion assigned to the spikes promotes self-correction of possible position and alignment errors in the hitch. This way, the location of the anchoring elements in the concrete modules does not require of high precision. 

          During OPERATION and CLIMBING of the crane: The anchorage completely relies on gravity, avoiding any mechanical locking device that could get blocked at height due to some dirt, material expansion, or deformation. Moreover, the round shape of the spike leads to optimum (homogeneous and centered) load distribution of the climbing device to the concrete tower. In such manner, larger loads can be withstood in all directions, resulting in higher performance of the self-climbing crane by increasing its lifting capacity and operational wind speed.

          During EXTRACTION of the spikes:It follows the same smooth and guided process as during the insertion. Furthermore, since no mechanical locking device is included, the  system cannot get jammed at heights where reparation is time consuming and expensive.

Hence, it is concluded that the design of the presented anchorage system favours the insertion, correct support, and extraction of the spikes, leading to a safe, reliable, maintenance and reparation-free system.

C. Performed studies 

The behaviour of the anchorage system has been analyzed through advanced finite element models for different concrete tower types: 

  • With varying wall WIDTH: From 15 to 35 cm.
  • With different tower segment LENGHT: From 3.6 to 20 m.
  • With diverse tower segment WEIGHT: From (30 t) 60 to 265 t. 

The anchorage has shown excellent response in all the studied scenarios, only requiring of some additional REBAR reinforcement around the anchorage area in certain cases.

The analyses have also shown that some plastification of the bottom part of the METAL FRAME (or inserts) embedded in the tower wall occurs during maximum loading conditions. This has been designed this way to optimize the anchorage.

The metal inserts are made of a lower resistance steel than the spikes so that plastification of the spikes is always avoided. The spikes are part of the self-climbing crane and will be constantly used for assembly of different towers and wind turbines. Hence, the perfect condition of these pieces must be ensured along the lifetime of the crane. However, the metal inserts are barely going to be used along the lifetime of the tower, only during construction or maintenance works. Thanks to the special shape of the system, allowing some plastification of the inserts in a localized area, does not compromise the correct subsequent functioning of the anchorage or blockage of the system. 

 This leads to an optimum design of the system while guaranteeing the perfect condition of the spikes and ensuring the correct operation of the system.

D. Other developments

  1. For already built concrete towers, where the metal inserts cannot be embedded during manufacturing, HWS has developed an anchoring version, in which a plate that can be easily bolted externally to the tower is proposed. This way, maintenance of existing towers through self-climbing crane technology is enabled.
  2. On the other hand, HWS is currently developing a different anchorage system for enabling self-climbing cranes to install steel towers. In this case, the anchorage points will be attached to a reinforced flange placed between the steel tower segments.  This flange will have four connection points at the same horizontal plane: the two outer ones will be used by one climbing device and the two internal ones by another one. 

Further information cannot be disclosed since it is currently under development and susceptible to patent.

E. Conclusion

  • In conclusion, HWS presents this development as a unique anchoring system applicable to any concrete tower and adaptable to any self-climbing device. 
  • This invention could be envisaged as the standard anchorage system to push and establish the use of self-climbing cranes in the construction of wind turbines.


«CENER met the self-climbing AirCRANE demonstrator, March 18th» (HWS)

ENG: On 18 March, Mr. Pablo Ayesa, General Director, and Mr. Antonio Ugarte,  Director of the Wind Energy Department, both members of the CENER (Spain´s National Renewable Energy Centre, https://www.cener.com/en/) met, at the workshops of the company KEYTECH (www.keytech.es) located in Lecumberri (Navarre), the demonstrator of the self-climbing AirCRANE, development granted by the European Commission, under «Horizon 2020-SME Instrument», No 804858 (Link to CORDIS: https://cordis.europa.eu/project/id/804858).
Also in attendance were Mr. Juanjo Etxalar and Mr. Telmo Sexmilo, representatives of CLAVE (https:/clave.capital) of Pamplona (Navarre), which manages the participation of the Basque industrial conglomerate MONDRAGON CORPORATION (https:/www.mondragon-corporation.com) in HWS, and that they will shortly expand its participation in HWS, together with INNVIERTE (https://www.cdti.es), to start the worldwide marketing of the developed solution.
In this way HWS Concrete Towers S.L. strengthens and guarantees its future.”
ES: “El pasado 18 de Marzo, D. Pablo Ayesa, Director General, y D. Antonio Ugarte,  Dtor. Departamento de Energía eólica, ambos de CENER (Centro Nacional de Energías Renovables, https://www.cener.com) conocieron en los talleres de la empresa KEYTECH (www.keytech.es) localizados en Lecumberri (Navarra) el demostrador de la grúa auto-trepante AirCRANE, desarrollado con ayuda de la Comisión Europea, Programa «Horizon 2020-SME Instrument», nº 804858 (Link a CORDIS: https://cordis.europa.eu/project/id/804858).
También asistieron D. Juanjo Etxalar y D. Telmo Sexmilo, representantes de CLAVE (https://clave.capital) de Pamplona (Navarra), quienes gestionan la participación del conglomerado industrial vasco CORPORACION MONDRAGON (https://www.mondragon-corporation.com) en HWS, y que van a ampliar en breve su participación en HWS, junto con INNVIERTE (https://www.cdti.es), para iniciar la comercialización mundial de la solución desarrollada.
De esta forma HWS Concrete Towers S.L. refuerza y garantiza su futuro.

Sector ENERGIA EOLICA: Perspectivas mundiales hasta 2.030

Según una reciente publicación de Wood Mackenzie (*), de Julio de 2021, el sector eólico va a crecer en la próxima década (2021-2030) MUNDIALMENTE a razón de una potencia instalada de entre 83 y 126 GW/año, esto es una media de 100 GW/año, frente a la media de 55 GW/año de la década anterior.

Por tanto casi se va a duplicar la POTENCIA INSTALADA, destacando en especial el gran incremento de las instalaciones Offshore (en el mar, que pueden ser cimentadas en el fondo o flotantes).


Unas definiciones y referencias para entender la información y las cifras:

  • Una central nuclear típica tiene una «potencia instalada» de aprox. 1 GW (= 1.000 MW).
  • Un «eólico» o «turbina eólica» actual, tiene una potencia (máxima) de entre 2,5 MW y 6,0 MW si es ON-shore (en tierra), y entre 6,0 MW y 15,0 MW si es OFF-shore (en el mar).
  • Por tanto, una nuclear equivaldría por ejemplo a unas 250 turbinas de 4,0 MW, en cuanto a «POTENCIA INSTALADA» …concepto que hace referencia a la máxima energía que podría producir, lo cual es un escenario ideal.
  • Porque otro aspecto a tener en cuenta es la «disponibilidad»: Una turbina eólica, por estar a merced de la aleatoria (!) intensidad del viento, produce energía eléctrica a plena potencia lo equivalente aprox. el 20-26% del tiempo, concepto/parámetro denominado «FACTOR DE CAPACIDAD» (que es clave para decidir una inversión), mientras que una central nuclear lo hace casi el 85% del tiempo.
  • Con ello, igualar la ENERGIA PRODUCIDA por una nuclear requeriría disponer de 960 eólicos de 4,0 MW.
  • Finalmente comentar que, frente a la E.Nuclear (85%) y la E.Eólica (22-26%), la E.Solar Fotovoltaica suele presentar un Factor de Capacidad de entre el 9 y el 12%.

(*) Wood Mackenzie (www.woodmac.com) es en la actualidad una de los más prestigiosos consultores que analiza permanentemente el mercado eólico, editando regularmente informes desde diversas perspectivas: globales, por países, nuevas instalaciones y mantenimiento, sobre fabricantes de piezas, etc…

«How much does the Wind Energy learn from Wind Sailing (…and viceversa) ?» (HWS)

As along last decade, completely new wind boats like Americans Cup AC75 monohull vessels (*) are appearing, completely new concepts with an exceptional efficiency which allows to fly over the sea near to 100 Km/h, or even surpassing (∼104 Km) with a Windsurf (**).

(*) The newest American’s Cup AC75 are 75 feet (22.86m) keel-less yachts,  which rise out of the water on hydrofoils and glide across the surface to reach speeds in excess of 50 knots (93 Km/h).

The Challenger yacht “Luna Rossa” had maxed out at 53,4 knots (99 Km/h), (…) and Team New Zealand’s “Te Rehutai” is rumoured to be even faster.

(**) On Thursday, November 18, 2021, in Namibia, Mr. Bjorn Dunkerbeck (the famous Dutch & Canarian 52-year-old famous windsurfer) broke that speed barrier, hitting 103,67 Km/h over a two-second time gap, and holding an average speed of 101,00 Km/h kilometers per hour over a 100-meter stretch of water.


«Certification of AirBASE Concept Design, awarded for the new generation (≥ 5.x MW) wind turbines» (HWS)

TÜV SÜD has Certified the DESIGN BASIS and CONCEPT DESIGN EVALUATION of HWS´ AirBASE foundation for onshore wind turbine generators (WTG).

The design evaluation has included the review of a real case scenario for one of the existing biggest wind turbines in the market, a 5.7 MW with a 150 m high steel tower.

The Certification process started last November 2020 and has lasted for around 6 months. Within the project, TÜV SÜD has performed a profound analysis of a new design methodology required to assess this innovative WTG support system. The technical validation included the review of the geotechnical and structural design, as well as the details of the construction process. The design was proved to comply with IEC21400-22:2010 and other applicable standards like Eurocode 2, Eurocode 3, Eurocode 7, and EIC61400-6.

The work required around 1,750 hours of engineering and the development of near 50 advanced finite element models, among which some general and local models of the soil-structure interaction were analysed. These models were performed in collaboration with the Spanish structural engineering firm INGZERO (www.ingzero.com).


This Certification is a major milestone for the commercialization of the AirBASE and paves the way for the market launch worldwide. In fact, it already created a lot of interest and traction among the key players of the wind sector.

To finalise the development process that started in December 2018 with the patent of the technology, HWS expects to build a pilot in Q1-2022.

About AirBASE technology

AirBASE concept disrupts current structural wind foundation systems by transferring the loads to the soil through four independent supports, which are connected to two/four precast posttensioned girders placed in a cross-shape. This way, the load transfer from structure to soil is optimized, which can become important as the wind turbine size increases.

The AirBASE foundation can be used for any wind turbine, with unlimited rated power, for any wind tower, made in steel or concrete, and any soil conditions.

The bigger the turbine, the higher the cost-effectiveness of the AirBASE.

Its main advantage is the cost reduction: savings can reach up to 35% in certain markets. Other advantages are the industrialization and standardization of the product, which reduces the risk of projects by enhancing the quality control process and reducing construction time and on-site resources.

«HWS is proud to present the self-climbing AirCRANE»

After 3 years of work HWS has finished the demonstrator of the self-climbing AirCRANE, a 30 t net-lifting capacity unit. Once the technology/concept has been tested and validated, HWS is confident in scaling it up to 250 t or down to 5-10 t (for construction).

In this type of cranes two concept should be distinguished:

  • How it climbs.
  • How it anchors to the structure.

In the case of the AirCRANE:

➜ The climbing process is mechanical, based on three innovative devices which moves along the main girder. This innovative concept introduces the possibility  to climb along vertical surfaces with trunk transitions, irregularities, inclined walls, etc.

➜ The anchoring system is conducted by means of a pair of spikes that are inserted into some cavities left in the tower. A reliable anchoring can be assured relying mainly in gravity force.

In all climbing systems, both processes are innovative, and hence, patented. In AirCRANE:  WO2019002654 and ES201930707.

Find more information in this self-explanatory video:

This project (from March 1st, 2018,to October 31st, 2020) has been developed with the support of the European Commission under the grant program “Horizon 2020-SME-Instrument Phase 2, no. 804858” (https://cordis.europa.eu/project/id/804858).

The first AirCRANE unit has been manufactured in KEYTECH (AMOND GROUP) (https://www.keytech.es/)  (http://amond-group.com) facility, located in Lecumberri, SPAIN.

We would be happy to show it to interested professionals of the wind energy sector.