Press Release
2021.9.28

Developed PC hybrid wind tower construction method "VT"
Aizawa High Pressure Enters Wind Power Business
120m class hyper onshore wind power road DNV GL design certification procedure started

Aizawa High Pressure Concrete Co., Ltd. (Headquarters Tomakomai City, President: Yoshihiro Aizawa) is raising the 80m-high steel tower, which is the mainstream of the current onshore wind power generation tower, to 120m class with a prestressed concrete (PC) tower. So, we have developed the PC hybrid wind power tower construction method "VT", which increases the power generation efficiency per tower more than four times, in technical cooperation with a major overseas wind power generation equipment manufacturer.

 

We have already started structural analysis required for design certification with DNV GL (headquarters in Oslo, Norway), which is one of the three major certification bodies in the world, from April, and we plan to launch it in the spring of 2022 at the earliest. VT is named after the Latin acronym "Ventus Turris," which means "tower of the wind."

■ Background of VT development

With the expiry of the feed-in tariff (FIT), the rebuilding of onshore wind power is expanding, and it is an urgent task for wind power generation operators to adopt a tower construction method with low power generation costs and high profitability. Although 120m class high towers will be the standard for the 5MW class, which will be the mainstay in the future, it is difficult to adopt large diameter steel towers due to transportation restrictions.

 

The panel-type tower construction method, in which relatively small precast concrete panels are manufactured at a factory, transported to the site, and then assembled, is not restricted by the construction site and is huge due to the structure in which the panels are integrated by PC technology. You can build a resilient tower that can withstand earthquakes and large typhoons. Furthermore, by raising the tower and increasing the size of the blades, the amount of power generated per tower can be reduced to more than four times that of the current model, and the cost of power generation can be reduced to about half. This will lead to a significant expansion of the installable area.


■ VT technology

The basic shape of the VT is an open octagon with alternating precast concrete (PCa) strut panels, and we have taken on the challenge of reducing the weight of the tower to the utmost. The PCa strut panel is assembled by temporarily assembling with the PC steel salary installed on the strut, and finally applying the necessary prestress with the PC cable to integrate the entire tower.
 

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The transition ring, which connects the concrete tower and the steel tower, has become the most important and difficult development theme for connecting members with different rigidity. By connecting the steel tower and the reinforced steel pipe with long bolts via the transition ring, it resists the eccentric load due to the difference in the outer diameter of the concrete tower and the steel tower.

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In addition, for the production of panels with columns, we adopted a variable formwork so that precast members of all sizes can be produced with one formwork, aiming to level the production and reduce costs.

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■ Structural verification with DNV GL

We have completed a mass model of VT with the cooperation of a major overseas wind power generation equipment manufacturer, and have been proceeding with structural analysis with DNV GL, which handles many certifications in the wind field since April. The transition ring, which is positioned as an important member in particular, requires detailed verification with an FEM model as a stress analysis of concrete and steel materials with different rigidity.
 

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■ Demonstration machine in Fukushima Prefecture

In August, we signed a basic location agreement with Namie Town, Fukushima Prefecture, aiming for co-creation of innovation. 』It was officially decided to build. The opening is scheduled for April 2023. A large 30-ton crane will be installed in the RDM manufacturing building to enable continuous production of VT panels with precast columns.

 

Renewable energy with high power generation efficiency by VT is the most suitable power to produce "green hydrogen" and "green ammonia", which are the trump cards of the decarbonization era. We are planning a field test such as construction of a VT demonstration machine in cooperation with Namie Town and reduction of hydrogen production cost by cooperation with wind power and an innovative hydrogen reactor, and high performance thin energy. We intend to promote collaboration with many stakeholders who are interested in our business.

[To the media]

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(Contact for inquiries regarding this press release)

Development Sales Headquarters Architectural PC / RE Supervisor: Kenji Omoto (080-2863-4147)

Development Sales Headquarters Strategist: Katsutoshi Mae (080-2863-4126)

Aizawa Institute of Technology President: Ryo Aizawa (080-2863-4151)

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