Sustainability through local resources
HASSLACHER Green Tower has created a licensing model on whose basis regional companies can produce the timber hybrid towers. Prerequisites are technical expertise and the implementation of the underlying quality assurance model.
Regional forest owners can be supported through the use of local wood resources (the trees to be cut down to make room for the wind power system) for the production of the timber hybrid tower, provided a HASSLACHER group sawmill is located nearby. To make sure round timber procurement takes place quickly, effortlessly and competently, dedicated regional buyers are available. Expertly and reliable acceptance of wood as the raw material (spruce and pine) is thus guaranteed in all qualities and in every market situation.
The towers are either produced at the German sites (Magdeburg and Kleinheubach bei Frankfurt) or Austria (Sachsenburg and Hermagor in Carinthia), additionally assuring regional value creation.
Monitoring and maintenance measures can be performed by regional companies with respective expertise in wood processing. By recycling the timber elements, they can be regionally reused for structural projects such as the construction of public buildings. Additionally, the timber hybrid tower helps the region’s citizens benefit from the wind park as its regional impact is perfect for citizen participation models.
Quality assurance in the production process
The supports and diagonals of HASSLACHER Green Tower’s timber hybrid tower are made from glued laminated timber (glulam). This is timber glued together from several board layers (so-called lamellas) in the same direction of growth.
Fire protection for timber structures
Eine der am häufigsten gestellten Fragen ist jene, nach dem statischen Tragverhalten des Holz-Hybrid-Turms in einem Brandfall. Da Holz als Brennmaterial bekannt ist, müsste sich demnach ein Brandherd in einer Holzkonstruktion schnell entfachen und das Feuer ungehindert ausbreiten. Aber entspricht das Meinungsbild den realen Verhältnissen?
Carbon Impact – Use of regional, regrowing resources, short transport routes thanks to close production sites
In order to further reduce carbon emissions and to maximise the value of the building material, a recycling concept was created for the timber hybrid tower’s timber elements. Thus, the supports and diagonals can be used for timber construction elements and reused in mass timber construction. The use of regional, regrowing resources, the shorter transport routes thanks to close production sites and the segmentable timber elements mark the tower concept’s further positive ecological impact.
The reusable tower
Circular economy is an indispensable part of our philosophy. First, the trees are removed from the forest, turned into elements for timber hybrid towers and after that, they are reprocessed and reused for other structural building projects. Once the timber hybrid tower’s life cycle of 20 years and the building’s 50-year life cycle have come to an end, the regrowing building material that is wood is used for other purposes down a cascade (e.g. chip or fibre based wood materials). Only at the very end of the cascade, its biomass is used to produce energy.
Do you have questions regarding the environmental footprint of the HASSLACHER Green Tower timber hybrid tower?
What forest regions and sawmills the round timber is sourced from strongly depends on the geographic location of the wood processing centre. This is due to the relationship between merchandise value and round timber transport volume. While sawn timber or further processed products can virtually be shipped all over the planet (by ship), the sourcing radius of round timber is limited to 150 to 200 km for economic reasons. Only in case of large-scale wind damage, larger distances can be accepted using entire trains. Since the production locations for the timber hybrid tower are currently located in Austria and Germany, the round timber is sourced from these and adjacent markets (Slovenia, South Tyrol etc.). Sustainable forest use is not only part of the HASSLACHER group’s generation-long philosophy and thus, a core element of its corporate vision, the company also possesses all required environmental declarations (EPD according to ISO 14025 and EN 15804+A2 as well as PFEC certificate (Programme for the Endorsement of Forest Certification Schemes) according to PEFC ST 2002:2013.
The fact that timber towers are better suited for forest locations than steel or reinforced steel structures is obvious. Why, then, are we mentioning that our timber hybrid tower is particularly suited for forest locations? It’s all in our “wood protects wood” weather protection system. This leaves the wooden structure exposed instead of covering it up with a diaphragm or coating. Additionally, this integrated weathering layer results in extremely low maintenance costs that only extend to an annual visual inspection. Not using lacquer gives our tower a much lower environmental footprint. To make our package complete, land owners can deliver the trees felled to create the wind farm areas directly to the HASSLACHER group.
Clear-cutting forest areas for wind power systems is a sensitive issue. Both land owners and local inhabitants are highly critical of large-scale clear cutting. However, the size of the systems currently set up requires adequately sized crawler cranes whose cantilevers require areas up to 200 m long in a single direction. To significantly reduce clear cutting, we are developing various assembly concepts. Since timber elements weigh much less than comparable steel elements, we are able to use much smaller mobile cranes all the way to the steel adapter. But we also develop assembly concepts involving rotating tower cranes. These flexible-height cranes, combined with our segmentable timber elements then allow for minimal clear cutting compared to current concepts. By the way, our timber frame structures are perfectly suited for connecting rotating tower cranes. Additionally, our timber hybrid tower system allows for the entire wind power system to be built gradually. This eliminates all waiting periods following the timber structure’s erection. This also contributes reducing the number of cranes required for erection and their various spatial requirements to one crane and allows us to select the most space-saving crane depending on location and availability.
Do you have questions regarding the removal and circular concept and the regional value creation involving the Green Tower timber hybrid tower?
For our timber hybrid tower, we have developed a second-life concept as well as a third-life concept. Once they have reached the end of their life as a timber tower for wind power systems, the glulam beams of the supports and diagonals are newly configured. These parts can then be used for structural engineering tasks. After that, the building material that is wood is used for other purposes down a cascade (e.g. chip or fibre based wood materials). Thus, the carbon sequestered in the wood can remain so for over 70 years, so that the HASSLACHER Green Tower GmbH is contributing actively to decarbonisation. This is about equal to the time a forest needs to entirely grow back to harvesting state. The simultaneous reforestation of forests and the extremely long service life of the material that is wood results in a unique carbon emission balance sheet for the overall concept.
The material that is wood is a regionally available, regrowing raw material. Thus, land owners can deliver the trees that accrue during clear cutting to the HASSLACHER group. The towers are made in Germany and Austria, the markets in which most of the timber hybrid towers are built. Due to an elaborate quality assurance system, regional production of the timber hybrid tower can also take place in other countries on the basis of a licensing model. The relatively simple individual foundations can furthermore be established by regional construction companies. The timber elements can also be structurally reused regionally.
This option definitely exists. But in this context, we need to mention two things. First of all, the supplied wood’s utilisation in the wind farms to be erected can only be guaranteed in financial terms (no direct utilisation). The reason for this is that every log has a different density, meaning that not every log is suited for the dynamic loads created by a wind power system. Secondly, delivery only makes sense if the location is within a 200-km radius of a HASSLACHER group sawmill. Due to the number and distribution of mills, Austria and Germany are both well covered.
Do you have questions regarding the Green Tower timber hybrid tower’s economic efficiency?
Due to the resource-friendly structure and ongoing rationalisation projects, the timber hybrid tower can be offered at common market prices. Furthermore, the timber hybrid tower exhibits a higher price stability than steel towers, as the price for the raw material wood fluctuates less. The timber hybrid tower boasts significant benefits in terms of its life cycle costs. Lower maintenance costs, longer service life and lower removal costs as well as earnings connected with its second life concept at the end of its life cycle make the timber hybrid tower not only the most ecological (thanks to its life cycle) but also the most economically efficient alternative.
Moreover, we are working on additional features/functions/additional value (wind+more) that our tower can produce in order to further improve its energy costs, the acceptance of wind power and the compatibility of nature and technology.
The lower the resource requirement, the lower the structure’s environmental footprint. Our timber hybrid tower was designed to be extremely resource efficient. If one converted the used wood into a closed wall structure, the load-bearing structure would only have a wall thickness of 7 cm! This low resource requirement is the result of its open timber frame design, years of accompanying research and development work with our partners and 125 years of experience with such timber structures within the group.
The investment required for the timber hybrid tower are competitive through
- minimal material use due to the use of an open timber frame construction at a converted load-bearing wall thickness of approx.. 7 cm
- Resource savings through the use of small-volume individual foundations
- low-costs logistics through segmentable elements.
- simple and quick assembly thanks to high degree of pre-fabrication and exclusively mechanical joints at the construction site
- most efficient overall structure due to 12 years of development work
- and therefore, attractive purchasing price for the erected overall structure.
- Low maintenance costs thanks to intelligent wood protection measures
- material value of the wood at the end of the useful life higher than removal costs (positive removal earnings)
- lower provisions for removal for the counties and thus, lower capital commitment
- stable raw material price of the wood when compared with steel
- no carbon pricing to the timber construction
- lower removal costs through simply removing the connecting material in the timber structure and the time-saving cutting of the relatively small individual foundations.
to wonders.
