The vital role of floating wind

The potential of offshore windpower is enormous

According to IEA, bottom-fixed offshore wind alone has enough growth capacity to serve the world’s total energy consumption. Adding floating wind to the picture, the total growth potential of offshore wind increases to 10 times the world’s total electricity consumption.

While this may sound theoretical and somewhat excessive, the huge capacity potential in floating wind is in fact a key component in the world’s transition to green energy. Excess electricity can be converted into fuels for sectors that cannot always be served by electricity, such as large parts of the transport and industrial sectors.

Floating foundations enable offshore wind power to serve important new markets. Freed from the geographical constraints of shallow water site availability, floating wind opens new paths towards a cost-effective green energy transition in many regions.

Apart from the North Sea and shallow water coastlines off China and the Eastern USA, most of the world’s population centers cannot be served by conventional bottom-fixed offshore wind. There is just not sufficient shallow-water area available.

For countries lacking the space for solar PV and not having large, shallow water areas for conventional, bottom-fixed offshore wind, floating offshore wind will often be the ideal means for the green transition.

The world is going to need much more green power

A full transition to green energy will require the supply of a lot more electricity than today’s global demand. Sectors like transport and industry can only partly convert to electric power and will need Power-to-X fuels from renewables.

In order to appreciate just how much more electric energy capacity is needed to meet the future need for PtX fuels, we can use Denmark as an example.

With a power load of 5 GW Denmark would need 14 GW installed offshore wind to meet the country’s present power consumption

5 GW

Breaking down the numbers:

  • 14 GW of offshore wind with a capacity factor of 50% leaves 7 GW gross average power, 2 GW more than Denmark’s average power load.
  • The 2 GW extra capacity is needed to accommodate the loss associated with electric energy storage, which we need for when the wind is not blowing.
  • We arrive at 14 GW installed capacity, to get 7 GW average, to get a little over 5 GW serving Denmark’s demand.

In other words, 14 GW of offshore wind capacity to serve the Danish electricity market. This capacity requirement is dwarfed, however, by the electricity demand of other sectrors. As an example, supplying the Danish shipping company Maersk with PtX fuel out of Denmark, the added national demand for offshore wind power would be 40 GW on top of the 14 GW needed for electricity.

This illustrates why floating wind is a vital strategic asset in the fight against climate change. The world is going to need much more power from renewables in order to fully abandon fossil fuels, and floating wind can deliver cost competitive green power of an unparalleled scale.

Harvesting the available offshore wind ressource

IEA has assessed the world’s technically viable opportunities for offshore wind power in collaboration with Imperial College London. Using the latest satellite data, the project mapped out in detail the speed and quality of wind along hundreds of thousands of kilometers coastline around the world.

This geospatial analysis has revealed that resources located in regions with water depths exceeding 50-60 m, where traditional fixed-bottom offshore wind installations are not economically attractive, exceed the shallower-depth resource by a factor of 10.

Driving down the cost of floating wind

Floating offshore wind has two cost increasing components that bottom-fixed offshore wind does not need. One is the mooring system and the other is the need for a flexible cable that can follow the movements of the floating foundation.

On the other hand, floating wind also has a number of cost advantages relative to bottom-fixed offshore wind, apart from being a solution to the challenge of water depth:

  • The floating structure can essentially be made as one size fits all. Allowing for differences in turbine size, the same floating foundation can be employed all over the world. This is a significant standardization-upside from today’s practice of having different foundations for different projects. Just as the wind turbine manufacturers deliver the same turbine for projects all over the world, we will be able to deliver the same foundations all over the world.
  • The floater can be assembled portside and towed out to sea without the need for an installation vessel. This solves the vessel availability challenge and significantly reduces costs.
  • The anchors for a floating offshore foundation can be laid without the percussion noise that is unavoidable with most types of bottom-fixed foundations. In many countries percussion noise from foundation piling is an important environmental issue.
  • Anchors for the floating foundation are much more robust to variations in soil conditions in the seabed than conventional bottom-fixed foundations, which are very sensitive to inferior soil conditions.

All of these factors serve to reduce the comparative cost of floating wind.

At Stiesdal Offshore Technologies we are accelerating the development of floating wind with our industrialized design approach, expecting our Tetra floating foundation concept to meet market demands for low-cost and fast deployment of floating wind.