Wind farms built downstream of other wind farms may have hampered their power generation due to slowed wind speeds, according to German researchers at Helmholtz Zentrum Hereon.
Since the first systems were commissioned in 2008, the expansion of wind energy in the German coastal areas has accelerated considerably in recent years.
Today, wind turbines with a capacity of about 8,000 megawatts run in German waters, which is equivalent to about eight nuclear power plants. Due to the limited space, wind farms are sometimes built very close to each other.
The researchers believe that downstream wind farms in such an arrangement are significantly slowed down and have detected “amazing” large-scale low wind patterns in such areas.
On average, these patterns can extend up to 35-40 km from the wind farm and up to 100 km in certain wind conditions.
This can reduce the energy yield of a neighboring wind farm by 20 to 25 percent. If wind farms are planned close together, these wake effects must be taken into account in the future, the team warned.
They used a computer model typically used by weather services to solve regional weather situations in great detail – in this case for the entire North Sea – and combined this with specific data about wind farms such as their surface area and the number and size of the turbines.
They used the wind farm planning for the North Sea from 2015 as a basis, which includes some facilities that have not yet been built.
The results anticipate a large-scale pattern of reduced wind speeds, showing the largest expansions during stable weather conditions, usually the case in March and April.
However, at other times of the year, such as November and December, the atmosphere is so mixed that the wake effects of the wind farm are relatively small.
“Conventional flow models for analyzing wind farms have very high spatial resolution, but only look at a wind field over a short period of time,” said researcher Dr. Naveed Aktar.
“In addition, these cannot be used to determine how a wind farm changes the airflow over a large area.
” Whereas in their current work the group has mainly focused on the extent to which the wind farms influence each other, they now want to investigate the influence of reduced wind speeds on marine life, including the salinity and oxygen content of the water, the temperature and the amount of nutrients in certain water depths.
Last month, the Biden administration approved its first large-scale offshore wind farm for the US. It hopes the project will launch a new domestic energy industry that will help eliminate emissions from the country’s electricity sector.