Overall

The MonobaseWind has been developed as an efficient foundation system for  40+ m waterdepth and 10+ MW wind turbine. This system solves the problem to install a heavy gravity base including wind turbine by splitting the system into a tower and a base that can slide with regard to each other. That way the whole system can be installed without the help of a heavy lift vessel or other bespoke vessel.

The ability to pre-installed the wind turbine on the base at a sheltered location greatly reduces the offshore weather risk for installation. It saves a weather sensitive offshore operation using expensive equipment to lift the turbine and blades in place. Also a large part of the turbine commissioning can be done inshore using onshore personell and on a 24/7 schedule.

Design

MonoBaseWind is a combination of a Monopile and a Gravity Base. The difference being that the Monopile is driven in the ground to find the bearing capacity to carry the wind turbine loads, while the Gravity Base sits on top of the ground and relies on it’s own weight to provide the support to the wind turbine. The resemblance being the above water part which is identical.

The design of the Gravity Base is governed by the structural strength required to take all the loads, the geotechnical properties of the seabed and the naval architectural design of the temporary conditions required to transport and install the turbine.

The structural details and general layout has been optimised for an efficient construction to reduce production time and costs.

MonoBaseWind is a combination of a Monopile and a Gravity Base. The difference being that the Monopile is driven in the ground to find the bearing capacity to carry the wind turbine loads, while the Gravity Base sits on top of the ground and relies on it’s own weight to provide the support to the wind turbine. The resemblance being the above water part which is identical.

The design of the Gravity Base is governed by the structural strength required to take all the loads, the geotechnical properties of the seabed and the naval architectural design of the temporary conditions required to transport and install the turbine.

The structural details and general layout has been optimised for an efficient construction to reduce production time and costs.

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A GBF is a a so called shallow foundation. This requires the top layers of the soil to have adequate capacity to bear all the loads from the wind, current, waves and weight acting on the system. 

In general most seabed locations in the North Sea are suitable for a GBF. In those locations where the top layers are too soft, dredging or skirts under the foundation can be applied to resolve this.

Seabed control and preparation is an integrated part of the design of the MonobaseWind foundation to control the bearing capacity and to control the vertical inclination of the wind turbine.

The temporary phases required to build and install the MonoBasewind dedicate the Naval Architectural design. The MonobaseWind, including the wind turbine as a valuable cargo, needs to be designed to be a stable platform to allow transportation and installation in a save and control way.

The Naval Architectural design concentrates on the mitigation of the seakeeping risk associated with the tow and installation of the turbine. Verification of the seakeeping design has been performed together with the Maritime Research Institute MARIN who performed a full seakeeping model test program. The tests confirmed the excellent seakeeping behaviour of the concept allowing a save tow up to the 1 year North Sea summer storm during tow. 

 

Installation

The main feature of the MonobaseWind concept is the installation method. Due to this system the MBW is able to carry the completely assembled wind turbine during installation which have a very positive effect on the overall costs and risks of the wind farm construction.

The procedure to install the MonobaseWind starts with seabed preparation. When finished the MBW will be towed to the offshore location where it will be positioned lowered to the seabed using three tugs and one service vessel.

Next the power cable will be installed and the final commissioning of the turbine can be performed. 

To finish, a rock dumper will install scour protection and production of clean energy can begin.

The transport from assembly site to the offshore site will be performed using normal offshore tugs. A spread of one main tug of 80 ton Bollard Pull and one guard vessel is usually adequate.

The tow can be designed to be weather unrestricted which greatly reduced the weather delays.

Waiting in the field for a suitable installation weather window is possible as the tow design conditions are much higher than for installation.​

Motions and accelerations on the Nacelle are limited as confirmed during the modeltests.

After arrival at the installation location the MonobaseWind will be positioned using three tugs. The lowering will be controlled from one service vessel equipped with the ballast control centre and a ROV to monitor the installation from an underwater view. 

During lowering the MonobaseWind will be unmanned. All system will be remote controlled. Visual monitoring of all systems will be provided using drones and remote sensing will be used to monitor the conditions of all ballast systems.

The systems will have full  redundancy and will be able to reverse the lowering process to further mitigate the risks.

After installation the electrical cable can be installed and the final commissioning of the turbine can start.

If needed a rock dumper will install scour protection around the circumference of the base to finalise the installation of the MonobaseWind.

Construction

The construction of the MonobaseWind starts with the fabrication of the foundation either in a graven dock or on the quayside. When finished the foundations will be transferred to a floating conditions and can be towed to a parking site or the assembly site near the offshore wind field.

At the assembly site the wind turbine tower, nacelle and blades will be installed and the systems will be integrated and commissioned. ​

At many locations around the world large graven construction docks are available. These docks provide excellent construction facilities and are readily available without the need for large upfront investments.

Many of the docks rely on the declining Offshore Oil & Gas industry market and are therefore available to serve the wind industry.  

A dedicated production site can be setup at any yard location around the world. Solutions for horizontal and vertical transport are available and will be cost efficient for large volume production.

An concept fabrication yard has been designed by Bosch Rexroth for MonobaseWind with a capacity of one fully assembled MonobaseWind per week.

Operations & Maintenance

The design of the MonobaseWind considers  all phases of the foundation. Also after the service life a solution to remove or re-use the foundation should be part of the design. Being part of a sensitive ecological system care must be given to minimise the impact of the system to the environment. 

MonobaseWind offers these solutions and as such contributes to the sustainability of our living environment

After the service life of the turbine the MonobaseWind can be removed using a reverse installation method.

Using air pressure the ballast tanks can be emptied and the MonobaseWind can be refloated. This can be done with the turbine still on the Monobase or removed before the refloating operation

After arrival at the installation location the MonobaseWind will be positioned using three tugs. The lowering will be controlled from one service vessel equipped with the ballast control centre and a ROV to monitor the installation from an underwater view. 

During lowering the MonobaseWind will be unmanned. All system will be remote controlled. Visual monitoring of all systems will be provided using drones and remote sensing will be used to monitor the conditions of all ballast systems.

The systems will have full  redundancy and will be able to reverse the lowering process to further mitigate the risks.

Due to the high durability of the concrete it can be made cost effective to re-power the foundations with the next generation turbines. Steel parts which are over their design life can be replaced.

During the service life of the turbine, marine life will develop on the concrete gravity base. Removing the base will disturb the marine life and might actually not be the best solution to decommission the field. 

To preserve the precious marine life, the gravity base can be converted to an artificial reef by removing the turbine and the column completely leaving only the base as artificial reef. 

Logistics

The logistical process to construct a wind farm using the MonobaseWind concept requires some rethinking of the supply chain. There are several specific advantages which require a redesign of the process to experience the full benefit of using a concept which allows the turbine to be installed and commissioned in shore.

A dedicated production site requires about 25 hectares of ground and quayside with minimum 10 m waterdepth.  Together with Bosch Rexroth MonobaseWind has performed the logistic design of such plant.

The supply of turbines, the fabrication speed and the offshore planning should be further developed to utilise the full potential of the inshore assembly of the wind turbine.

Overall

The Floater, Monobase Wind’s floating offshore wind turbine foundation, is under development to provide an efficient solution for  100+ m waterdepth, 10+ MW wind turbines. This system solves the problem to install wind farms at highly profitable locations in terms of wind speeds that are currently in-exploitable due to water depths and its installation constraints. Like the Gravity Base Foundation, allowing for installation of the complete system without the need for a heavy lift vessel or other bespoke vessel.

The ability to pre-install the wind turbine on the foundation at a sheltered onshore / in-shore location greatly reduces the offshore weather risk for installation. It reduces a weather sensitive offshore operation using expensive equipment to lift the turbine and blades in place. Also a large part of the turbine commissioning can be done inshore using onshore personell and on a 24/7 schedule.

More information about the developments coming soon! 

The MonobaseWind has been developed as an efficient foundation system for  40+ m waterdepth and 10+ MW wind turbine. This system solves the problem to install a heavy gravity base including wind turbine by splitting the system into a tower and a base that can slide with regard to each other. That way the whole system can be installed without the help of a heavy lift vessel or other bespoke vessel.

The ability to pre-installed the wind turbine on the base at a sheltered location greatly reduces the offshore weather risk for installation. It saves a weather sensitive offshore operation using expensive equipment to lift the turbine and blades in place. Also a large part of the turbine commissioning can be done inshore using onshore personell and on a 24/7 schedule.

MonoBaseWind is a combination of a Monopile and a Gravity Base. The difference being that the Monopile is driven in the ground to find the bearing capacity to carry the wind turbine loads, while the Gravity Base sits on top of the ground and relies on it’s own weight to provide the support to the wind turbine. The resemblance being the above water part which is identical.

The design of the Gravity Base is governed by the structural strength required to take all the loads, the geotechnical properties of the seabed and the naval architectural design of the temporary conditions required to transport and install the turbine.

The structural details and general layout has been optimised for an efficient construction to reduce production time and costs.

MonoBaseWind is a combination of a Monopile and a Gravity Base. The difference being that the Monopile is driven in the ground to find the bearing capacity to carry the wind turbine loads, while the Gravity Base sits on top of the ground and relies on it’s own weight to provide the support to the wind turbine. The resemblance being the above water part which is identical.

The design of the Gravity Base is governed by the structural strength required to take all the loads, the geotechnical properties of the seabed and the naval architectural design of the temporary conditions required to transport and install the turbine.

The structural details and general layout has been optimised for an efficient construction to reduce production time and costs.

A GBF is a a so called shallow foundation. This requires the top layers of the soil to have adequate capacity to bear all the loads from the wind, current, waves and weight acting on the system. 

In general most seabed locations in the North Sea are suitable for a GBF. In those locations where the top layers are too soft, dredging or skirts under the foundation can be applied to resolve this.

Seabed control and preparation is an integrated part of the design of the MonobaseWind foundation to control the bearing capacity and to control the vertical inclination of the wind turbine.

The temporary phases required to build and install the MonoBasewind dedicate the Naval Architectural design. The MonobaseWind, including the wind turbine as a valuable cargo, needs to be designed to be a stable platform to allow transportation and installation in a save and control way.

The Naval Architectural design concentrates on the mitigation of the seakeeping risk associated with the tow and installation of the turbine. Verification of the seakeeping design has been performed together with the Maritime Research Institute MARIN who performed a full seakeeping model test program. The tests confirmed the excellent seakeeping behaviour of the concept allowing a save tow up to the 1 year North Sea summer storm during tow. 

 

The construction of the MonobaseWind starts with the fabrication of the foundation either in a graven dock or on the quayside. When finished the foundations will be transferred to a floating conditions and can be towed to a parking site or the assembly site near the offshore wind field.

At the assembly site the wind turbine tower, nacelle and blades will be installed and the systems will be integrated and commissioned. ​

At many locations around the world large graven construction docks are available. These docks provide excellent construction facilities and are readily available without the need for large upfront investments.

Many of the docks rely on the declining Offshore Oil & Gas industry market and are therefore available to serve the wind industry.  

A dedicated production site can be setup at any yard location around the world. Solutions for horizontal and vertical transport are available and will be cost efficient for large volume production.

An concept fabrication yard has been designed by Bosch Rexroth for MonobaseWind with a capacity of one fully assembled MonobaseWind per week.

The main feature of the MonobaseWind concept is the installation method. Due to this system the MBW is able to carry the completely assembled wind turbine during installation which have a very positive effect on the overall costs and risks of the wind farm construction.

The procedure to install the MonobaseWind starts with seabed preparation. When finished the MBW will be towed to the offshore location where it will be positioned lowered to the seabed using three tugs and one service vessel.

Next the power cable will be installed and the final commissioning of the turbine can be performed. 

To finish, a rock dumper will install scour protection and production of clean energy can begin.

The transport from assembly site to the offshore site will be performed using normal offshore tugs. A spread of one main tug of 80 ton Bollard Pull and one guard vessel is usually adequate.

The tow can be designed to be weather unrestricted which greatly reduced the weather delays.

Waiting in the field for a suitable installation weather window is possible as the tow design conditions are much higher than for installation.​

Motions and accelerations on the Nacelle are limited as confirmed during the modeltests.

After arrival at the installation location the MonobaseWind will be positioned using three tugs. The lowering will be controlled from one service vessel equipped with the ballast control centre and a ROV to monitor the installation from an underwater view. 

During lowering the MonobaseWind will be unmanned. All system will be remote controlled. Visual monitoring of all systems will be provided using drones and remote sensing will be used to monitor the conditions of all ballast systems.

The systems will have full  redundancy and will be able to reverse the lowering process to further mitigate the risks.

After installation the electrical cable can be installed and the final commissioning of the turbine can start.

If needed a rock dumper will install scour protection around the circumference of the base to finalise the installation of the MonobaseWind.

The logistical process to construct a wind farm using the MonobaseWind concept requires some rethinking of the supply chain. There are several specific advantages which require a redesign of the process to experience the full benefit of using a concept which allows the turbine to be installed and commissioned in shore.

A dedicated production site requires about 25 hectares of ground and quayside with minimum 10 m waterdepth.  Together with Bosch Rexroth MonobaseWind has performed the logistic design of such plant.

The supply of turbines, the fabrication speed and the offshore planning should be further developed to utilise the full potential of the inshore assembly of the wind turbine.

The design of the MonobaseWind considers  all phases of the foundation. Also after the service life a solution to remove or re-use the foundation should be part of the design. Being part of a sensitive ecological system care must be given to minimise the impact of the system to the environment. 

MonobaseWind offers these solutions and as such contributes to the sustainability of our living environment

After the service life of the turbine the MonobaseWind can be removed using a reverse installation method.

Using air pressure the ballast tanks can be emptied and the MonobaseWind can be refloated. This can be done with the turbine still on the Monobase or removed before the refloating operation

After arrival at the installation location the MonobaseWind will be positioned using three tugs. The lowering will be controlled from one service vessel equipped with the ballast control centre and a ROV to monitor the installation from an underwater view. 

During lowering the MonobaseWind will be unmanned. All system will be remote controlled. Visual monitoring of all systems will be provided using drones and remote sensing will be used to monitor the conditions of all ballast systems.

The systems will have full  redundancy and will be able to reverse the lowering process to further mitigate the risks.

Due to the high durability of the concrete it can be made cost effective to re-power the foundations with the next generation turbines. Steel parts which are over their design life can be replaced.

During the service life of the turbine, marine life will develop on the concrete gravity base. Removing the base will disturb the marine life and might actually not be the best solution to decommission the field. 

To preserve the precious marine life, the gravity base can be converted to an artificial reef by removing the turbine and the column completely leaving only the base as artificial reef. 

The Floater, Monobase Wind’s floating offshore wind turbine foundation, is under development to provide an efficient solution for  100+ m waterdepth, 10+ MW wind turbines. This system solves the problem to install wind farms at highly profitable locations in terms of wind speeds that are currently in-exploitable due to water depths and its installation constraints. Like the Gravity Base Foundation, allowing for installation of the complete system without the need for a heavy lift vessel or other bespoke vessel.

The ability to pre-install the wind turbine on the foundation at a sheltered onshore / in-shore location greatly reduces the offshore weather risk for installation. It reduces a weather sensitive offshore operation using expensive equipment to lift the turbine and blades in place. Also a large part of the turbine commissioning can be done inshore using onshore personell and on a 24/7 schedule.

More information about the developments coming soon!