The Future of Wind Energy Is In the Sea

The future of wind energy, one of the most significant renewable sustainable mix, passes through the seas. This is the panorama, challenges and opportunities of this niche.

We are experiencing one of the most interesting moments in the modern energy history: the transition from an energy model based on fossil fuels to one based around renewable energies and energy efficiency. The renewable technologies on which this change of model is based are the wind and solar photovoltaic.

The technological challenges that these renewable technologies posed have been overcome thanks to the efforts in R + D + i, leading to a reduction in costs that has surprised even the experts of the sector. Nowadays, it is cheaper to generate one kWh (kilowatt hour) using photovoltaic panels (3.2 - 4 cents / kWh) and wind turbines (2.6 - 5 cents / kWh), than using fossil fuels (nuclear : 10.1 - 17 cents / kWh, gas-combined cycle: 3.7 - 6.7 cents / kWh).

We are even reaching, in many countries like Spain, the tipping point or point of no return: that moment in which producing energy from new renewable facilities is cheaper than using existing fossil fuel plants.

Particularities of offshore wind

When we speak of wind energy, we all think of windmills installed on land throughout our geography, what is called onshore or terrestrial wind. However, there is a technology that is called to play an important role in the new energy model: offshore wind or offshore wind.

The offshore wind is based on the installation of wind turbines in the sea to extract the energy from the wind, presenting some advantages with respect to land-based wind. At sea, wind speeds are higher than those available on land, which increases the power that can be generated by a wind turbine with the same blade size.

In addition, the wind in the sea is affected by many fewer obstacles than on land, so the wind turbine can run for a greater number of hours throughout the year and requires a lower tower height compared to a land-based wind turbine. . As wind turbines are located in the sea, they have a visual impact much lower than terrestrial ones.

Finally, offshore wind energy allows electricity generation to be brought closer to consumption, achieving a more efficient electrical system. Coastal regions, both in Spain and in many other countries, tend to have high population densities. In these areas, with little surface per person, the installation of wind turbines in the sea is a good solution.

However, despite these benefits, the installation of these wind turbines in the sea has had to overcome numerous challenges, which has caused that today is still an expensive technology, with prices ranging between 7.2 and 12.6 euro cents / kWh. However, they are beginning to approach the costs of generating fossil technologies, and in fact, in some locations in the North Sea, the construction of the first offshore wind farms without state aid has already been announced.

Challenges imposed by the ocean

But, to reach this point, they have had to overcome a large number of challenges. One of the most problematic in the beginning, but which has already been overcome, was corrosion accelerated by the saline environment in the sea. This problem forced a large number of components to change prematurely in the Horns Rev wind farm.

Another challenge that had to be overcome was the transmission of the energy generated by the turbine to the coast through submarine lines. This is done in direct current, in front of the AC transmission normally used.

To reduce energy costs, the size of the turbines has increased, reaching powers of 10 MW (megawatts) today. To minimize maintenance costs, which requires ships or helicopters (with the high cost that this entails), some of the systems are duplicated in order to continue working in case of failure.

Finally, one of the main challenges of offshore wind is the anchoring of turbines to the seabed. In seas whose sea floor has depths less than 50 meters, as in the case of the North Sea where most of the marine wind turbines are concentrated, the wind turbines are anchored to the sea by means of a rigid structure. However, for higher depths, floating structures are needed, which would later be tied to the ground.

The challenges of implementing

In Spain, whose industry is a leader in the wind sector, in the offshore segment there is only one marine wind turbine, located in the Canary Islands. The Spanish coasts have the characteristic of having depths greater than 60 meters at distances relatively close to the coast, which is why floating structures are required to stabilize wind turbines and anchor them to the sea. This fact, together with unfavorable energy policies for renewable energies in recent years, have meant that this technology has not been implemented in our territory.

Elisa project, for the construction of an offshore offshore wind turbine in Gran Canaria.
However, floating structures for wind turbines are already being commercialized, allowing the expansion of offshore wind to a large number of regions where it was not technically viable until now.

In conclusion, the continuous industrial development and the turn in the Spanish and world energy policy that we have recently lived presage that we will not be long in seeing these machines in our seas and around the world. Offshore wind is called to play an important role in fulfilling the environmental commitments acquired in the Paris Agreement in 2015.