How CFD modelling improved ACC wind protection at Coryton Power Station

Gary Dicker, our UK, European and Middle East wet and dry cooling specialist, reflects on our work at Coryton Power Station, including what we learned from the original wind protection screen installation, why the screens were replaced almost two decades later, and how a tailored approach using computational fluid dynamics (CFD) modelling can maintain long-term performance.

To read the full article, see the online March 2026 edition of Modern Power Systems.

Located 30 miles east of London, on the River Thames, Intergen’s Coryton Power Station is a 800MW combined cycle gas turbine plant, using both gas and steam turbines to generate electricity. It has provided power to around 800,000 homes since 2002. 

The plant uses a bank of A-framed air-cooled condenser (ACC) systems. An ACC relies on fans drawing air across finned tubes to condense exhaust steam back into water.

This change, from gas to liquid, helps create a vacuum within the system, which is key to maintaining cooling efficiency.

ACCs therefore play a vital role in power generation, particularly where dry cooling offers an alternative to water-based systems. But, while the systems reduce reliance on water, the trade-off is that their performance can be heavily affected by wind.

After nearly two decades in service, Galebreaker’s original wind protection screens, which had protected its ACCs since 2005, had reached the end of their lifespan, creating an opportunity to reassess the site using updated CFD modelling, rather than simply replacing them like for like.

Coryton Power Station is located on the River Thames, 30 miles east of London. Its exposed setting leaves the ACC vulnerable to wind moving across open land.ation is located on the River Thames, 30 miles east of London. Its exposed setting leaves the ACC vulnerable to wind moving across open land.

Why wind impacts air-cooled condensers

When wind disrupts airflow around an ACC, it can create resistance, or ‘back pressure’, on the fans. As static pressure rises, fans can struggle to move air effectively. In some cases, they continue rotating but move less useful airflow, a process known as ‘pumping’.

Other effects can include wind shear, hot air recirculation and increased dynamic fan blade loading. For plant operators, this can reduce cooling performance, lower turbine efficiency, increase maintenance costs and make it harder to maintain consistent power output.

“Everything is subject to wind – you can’t get away from it,” says Gary, a mechanical engineer with more than 20 years’ experience optimising industrial and power plant cooling performance – and who was central to the Coryton upgrade project.

“The purpose of wind protection is not to push a plant’s output beyond its original design specification. It’s to help recover lost performance that happens when wind starts affecting airflow.”

In more severe cases, the commercial stakes are higher. Wind-related ACC cause plant de-rating, lost revenue or financial penalties.

“When wind disrupts ACC performance, it can directly affect a plant’s ability to meet its agreed output to the grid,” explains Gary.

“Operators can be fined for not delivering the energy they committed to. For others, it can mean reduced output or missed revenue opportunities during periods of high demand.”

This is particularly important for base-load plants, which need consistent performance to maximise output, and for plants delivering power at peak times, where demand is high and a premium is offered – making the financial impact much greater.

Building on the original Coryton installation

Over time, Coryton began facing some of these performance issues from high winds, including back pressure and mechanical stress on the system’s fans. 

Galebreaker’s original Coryton wind screen installation is covered in an earlier Coryton Power Station case study, while the original technical performance report from the first installation is also available online: Coryton technical case study.

The earlier report showed how wind protection improved ACC performance during windy conditions.

At the time, average site wind speeds were recorded between 2.8 m/s and 4.3 m/s, with the windshields improving ACC vacuum by 4.8mbar at wind speeds of 3.6 m/s. The report also noted greater improvements at higher wind speeds.

For the Coryton replacement project, the challenge was different. The existing screens had delivered a long service life, but replacement provided a chance to reassess the ACC using modern modelling tools and a more refined understanding of how wind behaves around the plant.

Why CFD modelling changed the approach

According to Gary, the most important stage in any wind protection project is understanding the site before discussing the hardware.

“Plants vary by construction, location and output, so there is no universal solution,” he says.

“When we’re called in to address wind-related issues, we need to understand how wind behaves around that specific plant.”

Galebreaker uses CFD modelling to assess how crosswinds are affecting a cooling system.

The model tracks millions of air particles as they move across the plant, hitting structures and interacting with cooling equipment. The outputs are quantitative as well as visual, showing areas where airflow is good or compromised with heat maps and velocity plots over each fan.

“Each fan behaves according to its own fan curve,” says Gary. “That means we can see which bank of fans are being starved of air, where hot air is concentrated and recirculating, and how that changes once screens are added.”

For operators, this shows where recoverable performance losses are possible and can help design a site-specific screen configuration.

Depending on the plant layout and modelling outputs, this may include perimeter screens, cruciform screens or a combination of screen types.

At Coryton, this CFD modelling allowed Galebreaker to simulate how wind moved around the ACC and test new screen configurations before installation.

“We fed in a year’s worth of wind and weather data so we could predict plant output with and without wind screens across every common operating condition,” says Gary.  

The modelling showed the plant was experiencing disruption from south-westerly winds, moving across open land adjacent to the River Thames, towards the ACC.

It also revealed opportunities to improve on the previous single barrier design.

“The original installation used a large open mesh full-height screen to block the wind,” Gary explains. “But the modelling showed this could starve the system of airflow.

“From this, we were able to refine the design and use lower-solidity high-level perimeter screens to reduce wind velocity directly beneath the fans.”

What was installed at Coryton

Following the modelling work, 26 new high-level perimeter screens were designed for Coryton’s ACC. The screens were 50% solid, engineered and manufactured in around three months, then installed over a three-week period.

The replacement screens were designed to reduce disruptive wind velocity while still allowing the ACC to draw the air it needs. Too little shielding may leave fans exposed to wind shear, while too much blockage can restrict airflow and reduce the benefit.

Galebreaker’s wind protection screens are designed to reduce disruptive wind velocity while maintaining airflow to the ACC fans.

Watch our Coryton Station installation video: Improving steam turbine output using Galebreaker Screens

A total of 26 high-level perimeter screens were manufactured and installed over a three-week period.

Results at Coryton

Reported performance data from Coryton showed a shift in turbine back pressure following installation of the replacement screens.

Lower back pressure improves the operating conditions for the steam turbine, supporting more efficient output. The results also sat alongside other station improvements that contributed to overall performance.

Reported data from Coryton showed a shift in turbine back pressure following installation of the replacement wind protection screens, supporting improved ACC cooling performance.

The chart compares seven-day operating periods at full load under similar weather conditions in January 2021 and January 2022.

• Plots: January 2021 performance (blue dots), before the Galebreaker replacement screens. January 2022 performance (orange dots), after installation, under similar weather and full-load conditions.
• Vertical axis: Steam turbine MW output, starting from 200MW.
• Horizontal axis: Steam turbine exhaust back pressure; lower back pressure means less restriction and better efficiency.
• Key takeaway: After installation, the plant achieved higher MW output at lower back pressure, reflecting improved ACC cooling performance.

How Galebreaker wind screens support ACC performance

Galebreaker’s wind protection screens are designed for power generation and industrial cooling environments where high winds can affect thermal performance, fan stability and output.

Key features include:

• CFD-informed screen designs tailored to site-specific airflow and wind conditions.
• Perimeter and cruciform screen configurations to improve ACC airflow and reduce wind-related performance losses.
• Lightweight fabric screens that attach to existing structures with minimal modification and reduced structural loading.
• Durable UV-stabilised, rot-proof and flame-retardant materials engineered for demanding industrial environments.
• Designs capable of withstanding wind loads up to 120mph, depending on project requirements.

Learn more about wind protection and performance solutions

Need support with ACC wind protection?

To learn more about Galebreaker’s support for power stations, visit our power stations sector page or explore wind protection and performance solutions.

Discuss your site’s requirements

Contact the Galebreaker Industrial team