3 questions to Florian Dupriez-Robin

Florian Dupriez-Robin is research project manager in risk analysis and reliability of ORE systems within the France Energies Marines team. We interviewed him as part of our Institute’s 2022 activity report.

What are the conclusions of the work on the reliability of floating substations?
The aim of the work in the MOSISS project is to optimise the OPEX of a floating electrical substation by adding in-service monitoring. Initially, we focused on how to carry out this in-service monitoring by improving a method initially developed by Nantes Université. We then assessed the impact of on-site inspection and/or in-service monitoring.
We carried out an assessment on the system as a whole and then on the components of a floating wind turbine, in particular the dynamic cable and the mooring lines. From this, we estimated a level of reliability, and the same exercise was carried out by adding in-service monitoring for certain failure modes. It should be noted that a poor assessment may be due to the quality of the sensor. We therefore need to standardise the information it provides and assess its lifespan and failure rate. We are currently preparing recommendations on the industrialisation of sensors, as well as an economic evaluation.

Why take an interest in isolated grids?
An isolated grid is complex to maintain. Electricity is very expensive, because fuel often must be transported, and in small quantities. And there are no economies of scale when it comes to maintaining the infrastructure. On islands, offshore renewables can be a good way of producing electricity (up to 50% of the mix). The impact is more direct with medium to low usage, and this can avoid the use of a generator. It’s carbon-free redundancy!

What is multi-criteria optimisation?
As part of the OPTILE project, we are optimising the electrical operation of the equipment on the basis of several criteria: the investment cost, the operating cost over 20 years, reliability and the associated tolerance, the rate of renewables in the mix with an optimum to be found to avoid excessive storage facilities, as well as the quantity of CO2 emitted / kW of electricity / kg of H2 over the entire life cycle. After six months of data collection, we began to define scenarios with different means of production and to use the methodology developed in MOSISS.

Photo credit: France Energies Marines