OFFSHORE WIND FARMS

OFFSHORE WIND FARMS

“Collaboration & Augmentation are the foundational principles of innovation” - Vaclav Smil

There is a pressing need to shift towards renewables in order to avoid climate crisis, which is more catastrophic than the covid-19 pandemic, for a sustainable future. Interestingly, every solution induces its own challenges in the system. In the course of this article, one such solution, offshore wind farms, would be discussed.

What are Offshore wind farms?

Offshore wind farms mean taking advantage of the high-speed winds available in the seas or oceans in order to harvest electricity. These technologies usually offer a higher capacity. Until a water depth of 60m, the turbines could be directly placed on the sea beds and are fixed however, for depths deeper than 60m the turbines are affixed onto structures called floaters which are further anchored to the ocean floors are employed.

The first commercial offshore wind farm was established in Denmark in 1991. Consequently, in the early 2000s, offshore windfarms became more popular and available throughout the EU. The current status quo of the offshore appears very provoking when analyzed. As of 2018, only 23GW of the global energy production comes from offshore technology with Northern Europe alone contributing around 80%. Fascinatingly, the offshore wind plants are multiplying at a rate of 13% per year which is greater than the on-shore wind plants growth rate (10%).

Technical Pros & Cons

Pros

1. The availability of high wind speeds at the seas increases the production rate when compared to onshore wind plants of the same size. For instance, a 3MW onshore can power 1500 households while 3.6MW can power up to 3300 households.

2. Wind speeds are consistent and well predicted due to the knowledge of the moon and tides.

3. Wind energy is compatible with storage technologies.

4. Spacing issues between turbines don’t pose a constraint anymore.

5. Fatigue effects on the turbine generators are reduced when compared to onshore wind plants.

Cons

1. Requires a sophisticated and highly reliable control system.

2. The design, manufacturing and operation of the plants have to counter challenges such as corrosion, fatigue, lightning strikes and biofuels.

3. Logistical issues with transporting and erecting turbines with very large diameters and blade lengths.

Environmental Concerns

Advantages

1. Noise pollution issues to mankind are curbed since offshore.

2. Seismic resilience is increased due to wind tracking helping to detect cyclones or tsunami waves earlier.

3. Arid lands could be better utilised for development purposes.

Disadvantages

1. Marine life is prone to high risk due to the noise and vibrations from the turbines and tends to affect the acoustic communication between marine life.

2. Rare earth elements might be used for construction leading to pollution and trade chokes. 

3. The transmission of electricity from offshore to shore involves electromagnetic radiations which impact the navigation senses of migratory birds etc. 

The societal concerns are pretty much positive. Since most of the population usually dwell in the coastal areas (especially in developed and developing nations like the US or Australia or India), the offshore wind with proper incentives would be embraced by the community. The added advantages of no sound pollution levels or the better reliability of the energy system further scale up the interests of the public.

The economical aspects appear disappointing, owing to the heavy reliance on LCOE for energy markets, due to major construction operations, which alone last for 15 years approx., mostly off the shore the capital investment skyrockets. Subsequently, the offshore plants must operate without any issues during their lifetime and with significant inputs in the form of opex for close to 25 years the economics doesn’t look very promising at the moment. Scientists and Engineers globally are working with vigour to cut down these costs.

However, right now as you read this, there is a lot of debate, research, discussion and erection of these type of technologies are going on. Hopefully, our Scientists & Engineers come up with better solutions to tackle these type of issues with renewables and make our globe a more sustainable and reliable one!

References

1. Corporativa, Iberdrola. “Offshore Wind Farms: the Sea Giants.” Iberdrola, www.iberdrola.com/environment/how-does-offshore-wind-energy-work. 

2. Nikitas, Georgios, et al. “Wind Energy.” Future Energy (Third Edition), Elsevier, 24 Jan. 2020, www.sciencedirect.com/science/article/pii/B9780081028865000165. 

3. “The Advantages of Having an Offshore Wind Farm.” 4subsea, www.4subsea.com/offshore-wind-farm-article/. 

4. “Addressing the Challenges of Offshore Wind.” TWI, www.twi-global.com/media-and-events/insights/addressing-the-challenges-of-offshore-wind#:~:text=The%20design%2C%20manufacture%20and%20operation,erosion%2C%20lightning%20strikes%20and%20biofouling. 

5. https://digitalcommons.library.umaine.edu/cgi/viewcontent.cgi?article=1060&context=honors

6. Toke, D., et al. “Assessing Environmental Impacts of Offshore Wind Farms: Lessons Learned and Recommendations for the Future.” Aquatic Biosystems, BioMed Central, 1 Jan. 1970, aquaticbiosystems.biomedcentral.com/articles/10.1186/2046-9063-10-8.