Sophie Broekers has discovered how offshore wind farms can deliver their electricity to land more cost-effectively through their hugely expensive cables. During her master’s project, she simulated a floating solar farm nestled among the wind turbines in the North Sea, yielding promising results. “In this project, the theory from my physics studies gained real significance.”

What fascinates you about offshore energy, energy from the sea?

“The best part about offshore energy is that the wind turbines at sea are much larger and taller, and thus generate a lot more power. For instance, off the coast of Noord-Holland lies the wind farm Hollandse Kust Noord, featuring 69 turbines spread across 90 square kilometres. It’s enormous.”

“Of course, constructing and maintaining such a farm is incredibly expensive. Currently, the costs for building and upkeep amount to around eighty euros per megawatt, with a third of that expense tied up in connecting to the power grid—essentially, the cables. To maximise energy capture even in strong winds, the cable linking the farm to the land has a capacity of 700 megawatts. However, this capacity is typically only utilised to about half its potential.”

And you’ve been working on a solution to this costly issue?

“I investigated whether we could use that large cable more efficiently by installing a solar farm between the offshore wind turbines. I conducted my master’s project at Whiffle, a company that employs Large Eddy Simulation for precise weather forecasting. They excel at predicting how far apart wind turbines should be positioned to avoid interfering with each other’s wind.”

“I aimed to determine if solar energy generated by solar panels situated among the wind turbines could complement the electricity produced by the turbines. Through simulations of solar radiation and cloud cover, I sought to find out if these solar panels would primarily generate power when the cable had excess capacity, meaning during low wind conditions. If the solar panels are mainly active when there’s also a lot of wind, a significant amount of energy would go to waste because it wouldn’t fit through the cable.”

Did you arrive at an encouraging conclusion?

“Absolutely! I discovered that wind and solar energy can complement each other so effectively at sea that establishing a solar field among the wind turbines could work very well. The wind farm generates 759 megawatts, and the simulation indicates that a solar farm could add another 700 megawatts. This nearly doubles the output, while only five percent more energy is wasted due to cable limitations. The capacity of the power cable would be utilised eleven percent more efficiently.”

Should we immediately start building offshore solar farms between the wind turbines?

“It’s certainly a challenge to install floating solar farms in the North Sea due to the large waves. Additionally, both wind and solar energy produce relatively little power during peak demand hours: early morning and early evening. A battery could help solve this issue. It could store excess energy to stabilise and even increase the amount of electricity flowing through the cable during high-demand periods.”

So, with a battery, the offshore park combining solar and wind energy would be complete?

“A battery would significantly enhance the park. However, my analysis revealed that we would need a 450-megawatt battery to guarantee a minimum of 1 megawatt in the cable, and such a battery doesn’t currently exist. The largest available battery is 400 megawatts, and it’s so expensive that deploying it would be unprofitable.”

What do you think is the most crucial factor for a successful energy transition right now?

“Investing in battery technology. We can harness all our energy from solar and wind, but until we can store it, we’ll never achieve 100 percent green energy. There has been too much focus on energy generation and not enough on storage. We are now facing grid congestion: an overloaded power grid that sometimes struggles to meet demand.”

“We need to combine many more technologies for a successful energy transition. The goal is to create energy hubs that align supply and demand in specific areas. CrossWind, which developed and built the Hollandse Kust Noord wind farm, is exploring whether a hydrogen plant within the park could convert excess capacity during sunny and windy periods into green hydrogen.”

What did you enjoy most about your project?

“I’m eager to contribute to green energy. During my physics studies, I spent a lot of time dealing with loads of data, calculations, mathematics and theories. This project made it practical and gave it real meaning. I worked with actual data, saw how much money is involved, and realised that the combination of wind turbines and solar panels at sea really holds great promise for the future.”

Have you faced any setbacks along the way?

“I ran simulations that required immense computing power, simulating an entire year in just a week and a half. There are numerous parameters involved in solar radiation. After three months of collaboration with someone who helped me a lot, I discovered that the simulations weren’t accurate enough due to a bug in the simulation software. Consequently, I had to discard three months of work and start over. Fortunately, much of the code I had written and the analysis methods were still usable. We fed new data into the programme, and ultimately, I managed to catch up on the lost time.”

Why did you choose to study physics?

“I wanted to understand what happens around me and how the world works. I’m very exact. After completing my bachelor’s degree in Eindhoven, I moved to Delft to pursue a master’s in Applied Physics, as there is a strong focus on green energy here.”

Did your studies help you during your project?

“Absolutely, the theory and knowledge I gained were very useful, but I also had to do many new things during the project. I had to analyse a lot of data and conduct an economic analysis as well. I picked that up quickly. I’ve particularly noticed that my studies have equipped me with strong analytical thinking skills.”

What are your future plans?

“I’ve just started at the consultancy firm Pondera. We provide technical advice on sustainable energy projects and investigate the impacts of offshore energy parks—not only in the Netherlands but also especially in Asia. We have offices in South Korea and Indonesia for example, where there is still a lot of potential to explore. I felt it was important for my work to remain highly technical.”