Middelgrunden

Middelgrunden Wind Farm Profile

Location and Geography

The Middelgrunden wind farm is situated on the Middelgrunden shoal, located in the Øresund, approximately 3.5 kilometers outside the harbor of Copenhagen, Denmark. This location was chosen due to the consistent and moderate wind conditions over the water, which are ideal for wind energy production.

Project History and Development

The idea for the Middelgrunden wind farm was first conceived in 1993 by a group of visionary individuals in Copenhagen. The project was initiated in 1996 by the Copenhagen Environment and Energy Office (CEEO) and the Middelgrunden Wind Turbine Cooperative, a group of local people. After overcoming initial opposition from the Danish Society for Nature Conservation, the project moved forward with the support of local communities and stakeholders.

Ownership and Operation

The Middelgrunden wind farm is jointly owned by two entities:

• Middelgrunden Wind Turbine Cooperative: This cooperative, comprising 10,000 local investors, owns 50% of the project.
• Copenhagen Energy (now part of HOFOR): The municipal utility company owns the remaining 50%. Despite separate ownership of the turbines (10 southern turbines by the cooperative and 10 northern turbines by Copenhagen Energy), both parties collaborate on operations and maintenance.

Technical Specifications

• Number of Turbines: The wind farm consists of 20 wind turbines.
• Turbine Capacity: Each turbine has a nameplate capacity of 2 MW, provided by Siemens Gamesa Renewable Energy (originally Bonus turbines).
• Total Capacity: The wind farm has a total installed capacity of 40 MW.
• Hub Height and Rotor Diameter: The turbines have a hub height of 64 meters and a rotor diameter of 76 meters, resulting in a total height of 102 meters.
• Foundations: The turbines are installed on concrete gravity base foundations, chosen for their cost-effectiveness and suitability for the shallow water depths (2-6 meters).

Performance and Production

• Annual Production: The wind farm generates approximately 90,000 MWh (or 100 GWh) of electricity per year, which is enough to power around 30,000 households. It delivers about 4% of the power for Copenhagen.
• Efficiency: The wind farm operates at a high efficiency, with the turbines generating power over 97% of the time due to the consistent wind conditions.

Construction and Timeline

• Construction Start: The project construction began in 2000.
• Commercial Operation: The wind farm entered into commercial operation in March 2001, making it the world's largest offshore wind farm at the time of its completion.

Innovative Features and Maintenance

• Corrosion Protection: The turbines are equipped with advanced corrosion protection systems, including improved painting, internal climate control, and de-humidifying devices to maintain a dry interior environment.
• Lubrication and Maintenance: The turbines feature automatic greasing systems and specialized gearbox oil filters. They are also equipped with nacelle-mounted hydraulic cranes to facilitate maintenance and service operations.
• Monitoring System: Each turbine has its own email address and is connected to a network-based monitoring system, allowing for real-time communication and data exchange between the turbines and the maintenance team.

Environmental and Community Impact

The project is an example of community wind energy, with strong local support and involvement from the outset. The cooperative and Copenhagen Energy worked closely with local communities and interest groups to ensure acceptance and minimal resistance during and after the construction phase.

Economic and Social Benefits

The Middelgrunden wind farm represents a significant investment in renewable energy, with an initial investment of approximately 48 million EUR. The project has contributed to the local economy and has been a model for community-driven renewable energy initiatives.