Overview on Leca® Lightweight Aggregate Concrete (LWAC)

Interview with Raul Murciego (Leca® Offshore Concrete Specialist)

Leca® Lightweight Aggregate Concrete

The Complexity of Offshore Construction

1.    One of the possible applications of LWAC is in offshore technologies, can you tell us more about it?

Raul Murciego: There are many projects with Offshore projects; ships, oil tankers and even oil & gas extraction platforms such as Trollwest. The use of lightweight concrete in a marine environment is recognized and proven, therefore this technology is applicable to the construction of floating platforms to support large wind turbines located offshore and in deep waters. This technology allows the size of the wind turbines to grow since it will be able to house larger diameter rotors, thus being able to generate more green energy in a more sustainable way.

We must be clear that this technology is under development and in the short/medium term we will be able to see 14 MW turbines with 222m diameter rotors. Can you imagine the size of the floating platform that a wind turbine with a 222m diameter rotor needs? These dimensions are difficult to imagine, for sure, but you can easily think of the size of a football stadium, and you won't be too far from reality. These are huge dimensions even for a single wind turbine but imagine the number of wind turbines it will take to reach the 17.6 GW that recent studies indicate will be needed by 2026.

Offshore Lightweight aggregate concrete
Offshore Lightweight aggregate concrete
Offshore Lightweight aggregate concrete
Offshore Lightweight aggregate concrete

2.    Can Floating structures be the solution to a greener electrical transition and guarantee a more sustainable future? Please share with us information on the DemoSATH – Saitec Offshore Technology project.

Raul Murciego: The energy transition to green energy is a reality. We currently live in a scenario where energy is key to the development of our society and must be obtained in the most sustainable way.

The DemoSATH is an innovative project. The floating platform on which the wind turbine is installed is 30m wide and 64m long. The rotor has a diameter of 96m. The installed wind turbine produces 2 MW and it will be installed in the sea, off the coast of Bilbao. The SATH (Swinging Around Twin Hull) technology consists of a catamaran-type double-hulled barge made up of two cylindrical floats of precast modular light weight concrete (LWAC) braced to each other and two submerged plates of the same material. It is characterized by having a single anchoring point, which allows it to be aligned with the direction of the wind to make the most of the wind resource. This prototype and technology are developed by the Spanish engineering company Saitec Offshore Technologies and has a very interesting design concept when compared to other prototypes that are being developed on the market.

Its main characteristic, from the point of view of its construction, is that it has a design that allows for it to be assembled in its entirety in the port and then towed later to its location. In other words, it does not require complicated and expensive assembly operations on sea, where working conditions are very difficult. Through constructing a lightweight structure, the total assembled structure can be transported out of the construction harbor even on relative shallow waters.

Furthermore, the construction of the windmills is simpler onshore, where good weather conditions are required to install the wind turbines. If the selected technology allows the turbines to be installed very quickly, it will allow more units to start up and therefore generate greater profitability.

We must also highlight that the DemoSATH pilot, due to its reduced weight of the total structure is a result of designing with lightweight aggregate concrete. This will allow these floaters to be built in a greater number of locations and ports around the world, improving the total sustainability of the design concept.

Another important fact is that building lighter parts makes it possible to build larger geometries with reduced resources such a cranes and manpower. We must not forget that these cranes in ports have very high costs and availability can be limited. Therefore, moving excessively heavy parts could create a bottleneck in production performance.

Sustainability is key for offshore windmill development. Not only to produce green energy, but also the way the projects are designed and conducted at inception. The key to better sustainability is the design. Using LWAC will allow the Design Engineer to optimize the design of the structure in many ways.

There are many characteristics that make the DemoSATH a very successful prototype of what this technology will be in the next 4 to 10 years.

3.    Innovation and sustainability go hand in hand for the future of large-scale engineering and this project was recognized with two awards, tell us more about them.  

Raul Murciego: A project that consists of generating energy through wind turbines floating offshore in deep waters is certainly innovative. This innovation has been recognized and has won awards as you have mentioned earlier.

The first award for this project was for the material chosen to construct the floater; The lightweight concrete. This award was given by the ANEFHOP association (It is the association of the most important concrete producers in Spain). The second award was from the Federation of Aggregates (FdA) of Spain for the Sustainable Development Award in the category of Innovation and Climate Change.

For LECA and Saint Gobain, it has always been of great importance to spearhead projects that, through innovation, new technologies and materials, allows us to take the next steps towards more sustainable solutions.

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