The main objective of this paper is to evaluate the use of floating wind turbines for isolated offshore systems. The energy analysis is a vital step at the initial phase of the project to define topologies that will be able to feed subsea systems, a water injection system is considered as a example. The first location that we decided to look in detail is one of the largest oil regions discovered in the last hundred years and it is located on the Brazilian coast. It is important to highlight that the development is on the technological frontier of a new type of floating wind turbine application for deep waters. The focus of the study is to validate the perks of this application, such as, the production of clean and green energy capable enough to satisfy the load requirements of a Water Injection Systems (WIS) for Oil and Gas (O&G) production, chosen among other possibilities of subsea systems as an example. Water injection is effective to improve the oil recovery in reservoirs, but conventionally involves high energy consumption, significant emissions and expensive infrastructure. This work investigates different configurations combining a wind turbine, diesel generator and batteries to supply power to the off-grid load, with the basic premise that WIS can follow the generation available from the wind turbine, since it does not require a fixed injection rate. In the energetic point of view, the main result shows that the use of wind turbine and li-ion battery can cut emissions by half and increase the energy efficiency of the system.