Siemens has launched a new AC grid access solution designed for connecting near-shore wind power plants to the grid. It stands in the place of conventional AC transformer platforms, consists of an offshore transformer module (OTM) attached directly to a wind turbine, and acts as a distributed transmission asset. Nominally rated in incremental 250 MW blocks it can be linked together to provide the required transmission capacity even for very large wind parks. It is said to be one third the size and weight of a conventional platform and could reduce substation costs by 40%.
The new device can be installed on a wind turbine foundation separately. As an alternative, it can be installed at the transition piece between foundation and turbine shaft like a balcony. It is said to be suitable for all wind power turbine models.
Its maker says that this space and weight reduction as made possible by focusing on the core electrical equipment and removing a number of optional ancillary systems, which also results in a reduced maintenance regime – no fans and diesel generators are necessary.
The use of liquid esters instead of mineral oil has made this solution more environmentally friendly. Esters have low flammability and are biodegradable, which is important for operations at sea. The development represents an important lever for Siemens in reaching its goal of reducing the costs of wind power generated offshore to below 10 euro cents/kWh by 2020. Construction, transport, installation, operation and maintenance of the platform account for a high portion of the total grid access costs. These costs could be reduced by up to 40% with this solution, and it is small and light enough to be mounted together with a turbine on the same foundation. This eliminates the need for a special heavy lift vessel. Furthermore, installation time should be shortened by around 20%.