Air conditioning on wind farms

Explainer blog

As part of the effort to reduce CO₂ emissions by 2030, the energy generated by offshore wind farms in Europe has increased by more than 700% over the past ten years. Like all other industrial processes, the operation of generating electrical energy and transporting it to shore needs cooling and air conditioning. How HVAC is implemented by wind farms at sea and the challenges this brings is the subject of this blog.

^{Annual installed capacity wind energy – source: WindEurope}

Wind energy supply chain

Offshore wind energy is generated by wind farms constructed in bodies of water like the North Sea to harvest wind energy and generate electricity. They are comprised of massive wind turbines built on fixed foundations in relatively shallow water. The rotating blades transfer kinetic wind energy into an alternating current of electrical energy.

The combined electricity generated by the turbines in the wind farm is directed to an offshore substation where the electricity is converted and transported to shore via high voltage cables. Once inland the electricity is transformed again at onshore substations.

HVAC on Offshore High Voltage Stations

HVAC installations are placed on offshore high voltage stations (OHVS) that are the heart of an offshore grid connection. These stations can be divided into AC and DC platforms depending on the relative current. Every wind field or park has its own AC platform, which is connected to a DC platform when the wind fields are exceptionally large or combined. To keep transport losses low, high voltage is mainly used for transporting large amounts of electrical energy. Offshore converter platforms therefore transform the electricity from wind turbines to high voltage and direct current.

Heat is generated during this conversion process, making cooling and ventilation a necessity. HVAC systems placed on these conversion platforms consist of the usual suspects such as air handling units, fan coil units and chillers. Chillers on AC platforms can be fitted with air-cooled condensers or – in case of a higher cooling demand – with sea- and fresh water systems.

Challenges

Thousands of people, machines and processes rely on electrical energy and that number is ever increasing. Downtime for an electricity plant has to be avoided and everything is built to ensure a constant stream of electricity. Like all other systems on the converter platform, the specs for the HVAC system are very high.

Most OHVS’s are normally unmanned, with some placed more than 100 kilometres offshore. This makes regular physical checking of the system unfeasible. Maintenance crews do visit the platform for service activities such as changing filters but this is all kept to a minimum. The HVAC system needs to operate at a high-performance level and is therefore made of durable materials like stainless steel or even titanium heat exchangers. 

Final thoughts

As part of the European Green Deal, the EU proposed in September 2020 to raise the 2030 greenhouse gas emission reduction target from 40% to at least 55% compared to 1990. In pursuit of a climate-neutral economy more and more countries are relying on electricity generated by wind parks, which is used for various purposes such as the production of green hydrogen. Because of its relatively shallow water, most European offshore wind farms are located in the North Sea.

^{Location of offshore wind farms in Europe – source: WindEurope}

Heinen & Hopman has already contributed to many offshore wind park projects, which generate over 11.000 MW of electric power. Contact one of our engineers to discover more about HVAC systems on offshore projects and offshore high voltage stations in particular or visit our renewables webpage.

And for everything HVAC, stay tuned to heinenhopman.com.