Question: Why floating offshore wind?
Answer: Offshore wind started with foundations because it is a well-known technology, but floating foundations become attractive as water depths increases and monopile or jacket foundations become less feasible. The foundation structures become to big; the amount of steel and installation costs outweighs the floating structures, also it needs to be anchored. The floating structures have another risk-profile entirely. There are pilot projects with floating wind projects around the world, a notable project is Hywind (link) - the first floating wind farm in the world. Hywind consists of five 6MW Siemens turbines near the coast of Aberdeen.
Question: Will renewable energy replace fossil fuels?
Answer: Yes, renewable energy will replace fossil fuels because it is a superior method for generating electrical energy. Since 2000 there has been an accelerating interest in renewable energy. Political will have backed renewable energy projects using the available natural resources, most prominently solar and wind, also wave, tidal and biogas projects. Today renewable power plants are more feasible than fossil fuel power plants, and the maturation is still ongoing. Clean air, and reduction in particles and CO2, is also a positive effect of using renewable energy.