hwstowers@hwstowers.com | +34 943 598 469

HWS | San Sebastian · SPAIN

| +34 943 598 469

HWS | San Sebastian · SPAIN

«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.

«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.

«Concrete Towers for Wind Turbines and Structural Damping» (HWS)

The wind market is demanding higher wind turbines, and even though engineers are doing a great job optimizing current steel towers, we are about to reach the limit of this technology. 

As an example, this video shows a slender wind turbine vibrating at its second bending mode excited probably by high wind velocities. 


  • How much is this phenomenon affecting the fatigue life of the system? 
  • Have we reached the boundaries of steel tower designs?

Hybrid or full-concrete towers could avoid these vibrations thanks to their higher structural damping. Could an ancient material—like concrete—be the solution?

«HWS presents its new product development: AirBASE RePOWERING» (HWS)

HWS has developed the AirBASE RePOWERING, an innovative precast concrete structure for repowering purposes that allows to reuse the old foundations while making the most of the existing infrastructure in the wind farm. 

This new product is based on HWS’ AirBASE technology: a new disruptive structural concept for wind turbine foundations, which is being successfully introduced in the wind energy market due to its cost-effectiveness.

AirBASE RePOWERING reuses the existing old foundation as ballast to improve the stability of the system, while adding on top two new precast girders in a cross-shape. The system is valid for any kind of soil and compatible with both shallow and deep foundations. 

Among its advantages are cost savings of up to 45% when compared to construction of a new foundation, as well as being and environmentally friendly solution. In fact, the AirBASE RePOWERING respects the landscape by avoiding occupation of new sites, construction of roads and working platforms, and demolition of existing infrastructure. In addition, it could help simplify the permitting process required for installation of a new wind farm.

In conclusion, the AirBASE RePOWERING could become the optimum solution for repowering wind farms from the decade of the nineties, which are close to their end-of-life.

Repowering of existing wind farms

The first installation of a wind farm dates back to 1975 in USA. In Europe, VESTAS produced the first wind turbine in 1978. Since then, commercial installation of these machines has progressively increased reaching in 2019 a total installed capacity of 651 GW, among which 251 GW are in Europe. In both cases, onshore wind has a high share of around 90% of the given figure (source: Wind Europe & Wood Mackenzie ).  

Europe has committed to meet a 30% share of electricity generated by renewables in 2030. Nowadays, 15% of the electric energy produced by European countries (EU-28) comes from wind resource. To deliver on this objective, it is foreseen that the installed wind energy power will have to be doubled in the next 10 years. In the meantime, by 2030, 50% of the current cumulative installed capacity in Europe will have reached the end of its operational life.

With this need to increase wind energy generation and the wind farms coming to their end-of-life period, the industry is considering the two following strategies:

➜ Lifetime extension: Some of the components of an existing wind turbine are upgraded (e.g. generator). The overall external layout of the farm remains unchanged (e.g. hub height, siting, size) (…). Depending on the Member State, this option is also referred to as refurbishment, enhancement, reactivation.

➜ Full repowering: The wind turbines are dismantled, and new more powerful wind turbines are installed. This also involves replacing other elements like the tower and the foundation, which should be accordingly designed for the new turbine. 

Onshore wind farm owners are currently finding much more attractive to extend the life of existing projects, since replacing foundations involves complexities and is expensive. However, as project life extension options are exhausted, owners will have to increasingly turn their attention to repowering.

This market demand has encouraged HWS to develop a new product: AirBASE RePOWERING. This technology faces the challenges of foundation replacement, making repowering much more appealing. 

WindEurope estimates that the yearly repowering volume grows from 1-2 GW in 2017 and stabilizes to 5.5-8.5 GW by 2027. The main markets will be Germany, Spain, Italy, Denmark, Portugal and France. 

Source: WindEUROPE (www.windeurope.org), 

June 2017, “Repowering and Lifetime Extension: making the most of Europe’s wind energy resource. THE EUROPEAN WIND INDUSTRY’S VIEWS ON MANAGING WIND ENERGY ASSETS AT THE END OF THEIR OPERATIONAL LIFETIME” (https://windeurope.org/policy/position-papers/repowering-and-lifetime-extension-making-the-most-of-europes-wind-energy-resource/).

«The HWS Self-Climbing AirCRANE is taking shape» (HWS)

We are happy to share how the AirCRANE is taking shape in Zizurkil (Guipuzkoa, SPAIN) and Lekunberri (Navarra, SPAIN).

After a long journey, it has become a reality!

Main Jib. Designed to be scalable and configurable to install any wind turbine in the market, the AirCRANE system is a cost-effective alternative for concrete towers of unlimited height. Its versatility makes it useful not only for installation and maintenance of wind turbines, but also for construction of bridge piles, central cores of skyscrapers, chimneys and many other applications.

We cannot wait to see it completed by the end of this summer and ready to climb a 28 m high wall.

Any of its design parameters can be adapted to the operational requirements, e.g. the height of its steel lattice structure is defined by the distance between the anchorage points. In the case of the attached figures, each climbing step has been set to 7 meters height, leading to a minimum of 20 meters length climbing structure.

At present, HWS is confident to complete the manufacturing and testing of the first AirCRANE by summer 2020. This unit will demonstrate its capabilities close to its manufacturing site by climbing a precast-concrete girder in vertical position (see attached pictures), which simulates a wind tower.

Afterwards, HWS will display the AirCRANE at Wind Europe 2020 in Hamburg



«AirBASE, a disruptive new solution for ONSHORE Wind Turbine FOUNDATIONS.»

The AirBASE, an innovative partially-precast foundation for Wind Turbine Generators (WTG) was patented in December 2018. Since then, HWS has studied its feasibility in different scenarios, covering a wide power range of TURBINES (from 2.X MW to 5.X MW), SOIL properties as well as TOWER heights from 90 m to 165 m, made in both STEEL and CONCRETE.

The AirBASE disrupts current STRUCTURAL FOUNDATION CONCEPTS by transferring the loads to the soil through four separated supports. These footings are connected through a pin-hole to two (or four) precast girders placed in a cross shape, PREVENTING the transfer of MOMENTS to the SOIL.

Among its advantages are the INDUSTRIALIZATION and STANDARDIZATION, which REDUCES THE RISK of projects by enhancing the quality control process and reducing construction time as well as on-site resources.

Focusing on COST-EFFECTIVENESS by balancing required materials with labour cost, HWS has developed several versions of the technology, each targeted to different markets, countries, wind farms, sites, etc. Some of these solutions include massive or ribbed foundations, with rectangular or inverted T girder cross-sections.

The performed feasibility and cost analysis prove the competitiveness of the AirBASE in all studied scenarios. While in gravity foundations the concrete volume increases exponentially with the size of the turbine, it rises only linearly using the AirBASE technology. Consequently, up to 35% of concrete volume can be saved.

The cost reduction of the AirBASE increases with the nominal power of the turbine, reaching up to 30%.

The AirBASE is expected to become the leading foundation design for the new generation of 5.X MW turbines at hub heights larger than 150 m, by avoiding casting high concrete volumes (700 – 1.000 m3) onsite.

This way, HWS facilitates the current trend in the wind industry, which is moving towards larger and more cost-effective turbines.