Floating offshore wind: French know-how driven by dynamic R&D is on the upswing

Floating offshore wind sector: a market with promising development

Floating offshore wind technology makes it possible to envisage the deployment of offshore systems in areas inaccessible to bottom-fixed wind turbines due to water depth of more than 60 m. Its proven efficiency also for shallow waters makes it a competitive alternative to the use of piles or gravity foundations. Developing this technology would allow better exploitation of offshore wind fields. The first pilot farms show an average load factor of 65% to 70% when the bottom-fixed wind turbines have a load factor of 40-45% offshore and 22% onshore. The distance from the coast offers a more constant wind with a higher average speed, but represents a strong constraint for the export of the power produced. The market is emerging, with development supported by several pilot farms, some of which are already in operation. Knowing that 80% of the offshore wind energy available in Europe is located in depths suitable for floating technology and that the additional operating costs compared to bottom-fixed wind turbines are lower than expected, the sector anticipates very rapid development. This is confirmed by the performance of current prototypes, which is better than initially forecast.

Reliability and performance issues

The main challenges for the deployment of floating offshore wind sector in France and internationally are :

The reliability of mobile systems over 20 to 25 years in a hostile marine environment,
A gain in performance conditioned by the minimisation of production losses linked to floating structure movements,
The reliability and robustness of the dynamic part of the power export cable,
The integration of future commercial farms with existing marine activities,
The setting up of an industrial sector and dedicated port areas,
The construction of an installation and maintenance chain with adapted means,
The economic attractiveness that requires achieving an average cost of energy produced that is competitive with other sources of decarbonated energy,
Applicable regulations and the acceptability of projects that can cause significant delays that then limit the deployment of technologies.

In France, calls for tenders for four pilot farms were awarded in 2016. The first productions are expected in 2022. In the framework of the law on multiannual programming of energy published in 2020, the French State announces commercial farms to be awarded as early as 2021. These elements underline the need to provide rapid responses to the challenges of floating offshore wind sector.

Wind resource, system design and environmental impact

France Energies Marines contributes to providing solutions for the floating offshore wind sector, mainly through collaborative R&D projects that enable :

Assessing the impact of climate change on wind resources and system design (2C NOW project),
Reducing uncertainties on the characterisation of wind resources and thus contribute to the optimisation of production (ARCWIND, CARAVELE, CASSIOWPE, POWSEIDOM and DRACCAR-NEMO projects);
Better characterising the physical environment, particularly wave fields, while taking into account the impact of breaking waves on floating structures (DIME, DIMPACT and OROWSHI projects);
Evaluating mooring solutions that reduce investment costs while guaranteeing a system payback, thus increasing performance, and propose adapted design standards (POLYAMOOR, MONAMOOR and BAMOS projects);
Improving the prediction of the service life of dynamic export cables, electrical substations and mooring lines in order to propose adapted monitoring solutions and optimise the maintenance plan and conservative design costs to cover uncertainties (OMDYN2, DYNAMO, LISORE, MOSISS, AFOSS-DC, MHM-EMR, ABIOP+, BIODHYL, POLYAMOOR, MONAMOOR, SUBSEE 4D and DIONYSOS projects);
Proposing innovative strategies to optimise the farm design and operations at sea (FLOWTOM, MUTANC projects);
Optimising environmental, societal and economic impact studies by proposing original models integrating the ecosystem in the broadest sense to support the acceptability of projects (TROPHIK, APPEAL and WINDSERV projects);
Supporting the choice of locations and future impact studies, in particular by proposing appropriate means and methods for data acquisition (GEOBIRD, ORNIT-EOF, ECOSYSM-EOF, SEMMACAPE and OWFSOMM projects);
Studying the potential environmental effects of the systems by assessing the effect of electromagnetic fields from submarine cables (SPECIES project), passive acoustic monitoring of benthos (BENTHOSCOPE and BENTHOSCOPE2 projects) or the quantitative assessment of metals released into the marine environment from galvanic anodes (ANODE project);
Identifying ways to improve the environmental and societal sustainability of offshore wind farms by analysing their life cycle (LIF-OWI project);
Developing a research platform at sea (FOWRCE SEA project);
Carrying out preliminary studies about the hydrogen offshore production (OPHARM and OPHARM2 projects),
Proposing multi-criteria optimisation for the supply of isolated grid (OPTILE project).

The recent launch of DRACCAR, the first French research platform at sea dedicated to offshore wind power, coupled with an innovative R&D programme, will improve the understanding of the interactions between offshore wind power and the environment, the optimisation of the design of wind turbines and allow co-construction of a permanent observation network of the seafronts.

Recommendations for the evolution of current standards

The various studies to which the Institute contributes aim to provide the sector with validated models, adapted measurement methods, representative data and recommendation reports based on recognised expertise. Two projects on biofouling (ABIOP+ and BIODHYL projects) provided decisive elements for the design of mooring lines and dynamic cables by qualifying and quantifying the growth of biocolonisation in the vicinity of future farms and measuring its effect on the behaviour of these critical components. The results of this project reinforce the confidence of developers in taking biofouling into account by proposing to standardise the characterisation protocol for this influential parameter. The work carried out as part of our site characterisation and design and in-service monitoring activity is conducted in the presence of certifying bodies and produces recommendations intended to develop current standards.

List of publications related to floating offshore wind (PDF)

Photo credit: Naval Energies

Projects

In progress

2C NOW

Climate change impact on offshore wind

In progress

DIMPACT

Design of floating wind turbines and impacts of energetic steep and breaking waves

Closed

DYNAMO

Dynamic cable monitoring

Closed

ABIOP

Accounting for biofouling through established protocols of quantification

Closed

ABIOP+

Consideration of biofouling using quantification protocols useful for engineering

In progress

AFOSS-DC

Architecture and design of floating offshore substation for direct current applications

Closed

ANODE

Quantitative evaluation of metals released into the marine environment from the galvanic anodes of ORE structures.

Closed

APPEAL

Socio-ecosystemic approach to the impact of floating wind farms

Closed

ARCWIND

Adaptation and implementation of floating wind energy conversion technology for the Atlantic Region

In progress

BAMOS

Behaviour and ageing of mooring using synthetic rope

Closed

BENTHOSCOPE 2

Understanding and monitoring of ORE impacts on the benthic compartment via a measurement platform dedicated to passive acoustic

In progress

BIODHYL

Biofouling characterization and description of hydrodynamic loadings

Closed

CARAVELE

Wind characterisation for offshore renewable energies applications

Closed

CASSIOWPE

Characterising the atmosphere and sea surface interactions for the deployment of offshore wind in the Gulf of Lion

Closed

COASTWAVE

High-resolution local analysis of wave and breaking variability from satellite imagery

In progress

COME3T

Committee of experts for offshore renewable energies environmental and socio-economic issues

In progress

DIME

Design and metocean: modelling and observations of extreme sea states for offshore renewable energies

In progress

DIONYSOS

Digital intelligent operational network using hybrid sensors / simulations approach

In progress

DRACCAR – NEMO

New methods for turbulence measurements and models in offshore wind

Closed

DUNES

Dynamics of hydraulic dunes and impact on ORE projects

In progress

ECOSYSM-EOF

Prefiguration of an observatory of marine ecosystems in interaction with floating offshore wind farms in the Gulf of Lion

Closed

ECUME

French working group on cumulative effects of ORE projects

Closed

EOLINK

Proof of concept for an innovative floating wind turbine

In progress

FISHOWF

Effective monitoring strategies to identify and evaluate effects of offshore wind farms and their export cables on fish communities

In progress

FLOWTOM

Floating offshore wind turbines operation and maintenance

Closed

FOWRCE SEA

Future offshore wind research center at sea

In progress

LIF-OWI

Environmental, socio-economic and technological challenges for life cycle assessments of offshore wind farms

Closed

LISORE

Innovative and cost-effective offshore substations for ORE by 2025

Closed

GEOBIRD

Development of an innovative geolocation tag for seabirds

Closed

MEDSEA CHECKPOINT

Assessment of the Mediterranean observational data system for targeted applications

Closed

MHM-EMR

Mooring health monitoring for offshore renewable energy systems

In progress

MODULLES

Modelling of marine dunes: local and large-scale evolutions in an OWF context

Closed

MONAMOOR

Modelling and monitoring of polyamide mooring lines

Closed

MOSISS

Monitoring strategies for innovative substations

In progress

MUTANC

Mutualised anchors for offshore wind farms

Closed

OMDYN

Dynamic umbilicals for offshore renewable energies

Closed

OMDYN2

Dynamic umbilicals for floating marine renewable energies technologies - Phase 2

Closed

OPHARM

Hydrogen and offshore wind: decision-support tools

In progress

OPHARM2

Advanced analysis for offshore production of hydrogen from offshore wind

In progress

OPTILE

Multi-criteria optimisation for offgrid marine renewable electrical production

In progress

ORNIT-EOF

Prefiguration of an observatory of the Gulf of Lion birdlife in interaction with floating offshore wind farms

In progress

OROWSHI

Offshore wind turbine design including joint wind-wave information in standard for hurricane-exposed sites

In progress

OWFSOMM

Offshore wind farm surveys of marine megafauna: standardisation of tools and methods for monitoring at farm scales

Closed

POLYAMOOR

Durable and flexible polyamide moorings for offshore renewable energies

Closed

POWSEIDOM

Deployment of wind and turbulence observations in the Mediterranean

Closed

SEMMACAPE

Monitoring and study of marine megafauna in wind farms by automatic characterisation

Closed

SPECIES

Subsea power cables interactions with environment and associated surveys

Closed

SUBSEE 4D

A digital twin to facilitate the operation of floating wind farms

Closed

TROPHIK

Modelling the role of offshore wind farms in modifying the functioning of coastal food webs and cumulative impact

Closed

VALARRAY

Optimisation software for tidal and floating offshore turbine arrays: state of the art, comparison and new tools specification

Closed

VALEF

Hydro-aero-elastic modelling of floating offshore wind turbines

Closed

WINDSERV

Towards a multi-model approach of indicators of ecosystem services

Recommendations for health monitoring of dynamic cables for floating offshore wind farms