Overcoming Design Issues in Port Redevelopment to Support Offshore Wind
By Principal Mark Mahoney at Anchor QEA, Senior Consultant Stephen Doran at Offshore Construction Associates, and Lead Consultant Mark Edwards at Offshore Construction Associates
Coastal communities are advancing port infrastructure ventures as they seek to support the growing offshore wind energy industry. As a newer industry, however, offshore wind energy calls for specialized equipment, services, and labor that ports will have to adapt to in order to be operational. Compared to warehousing or commercial shipping, the offshore wind energy industry requires different services and support from ports. Thus, port redevelopment requires a major shift in the design approach to accommodate unique handling, storage, and transport.
For example, equipment and proximity needs require a great deal of space, both on the landside and waterside. A good installation and staging port must include heavy-lift capacity, adequate laydown for handling and storage of large components, and unimpeded access for larger, specialized vessels that transport large components. Ports must also have proper deep-water draft and open access for offshore construction operations.
As widespread interest in offshore wind energy expands, understanding the scale and scope of port redevelopment to support this industry is essential.
Solving Design Issues in the Port Redevelopment Process
Proper Equipment and Access to Manufacturing: A single offshore wind farm project will usually include 80 to 150 steel foundations, each weighing upwards of 1,000 tons, which must be stored and moved in two parts, in addition to the associated number of turbines and hundreds of miles of offshore power cable. In Europe, it is not uncommon to see hundreds of turbine blades that are over 250 feet long being stored at offshore wind farm port facilities ready to be loaded out for a single project.
These facilities often comprise construction and port facilities located together to avoid road transportation of the huge structures. In facilities such as the Siemens Gamesa Renewable Energy site in Hull, United Kingdom, the turbine blades are manufactured at a facility adjacent to the quayside, where the full turbines are loaded onto the installation vessels. Turbine hubs and nacelles (which contain the turbine and generator equipment) are shipped in from the other quayside manufacturing sites in Europe such as Cuxhaven in Germany. Turbine towers are often assembled at the Hull site from smaller pieces shipped in from similar locations such as Campbelltown in Scotland.
These wind turbine blades are being stored at a European port prior to installation (photo provided by Offshore Construction Associates).
The vessels installing the turbines and foundations at the offshore wind farms are also often jack-up vessels with the appropriate lifting capacity to install the components. This means quayside cranes are not necessary for loading the installation vessels, although they are necessary for unloading the components from transportation vessels from their fabrication sites. It also means the seabed next to the quayside must also be able to support these vessels jacking up repeatedly at the same location.
Spatial Requirements: Ports that support offshore wind energy must be specifically designed to accommodate partial assembly and shipping of large components. The port redevelopment process therefore often includes decommissioning, demolition, and disposal of obsolete structures to meet the spatial requirements to effectively support construction, operations, and maintenance of offshore wind energy. For example, industrial structures that contain hazardous materials must often be torn down to create large, open lay-down areas that can accommodate staging of wind turbine components.
Decommissioning, demolition, and disposal can present logistical and regulatory obstacles, which can also be very costly; however, with proper waste material management, this cost can be reduced by preparing demolished materials for beneficial reuse, rather than sending them to a demolition facility or landfill. Beneficial reuse is essentially reusing waste materials in a productive way, thereby providing environmental and economic benefits.
Managing contaminated sediment and dredged materials may be necessary due to the special dimensional restrictions for navigation pathways to the wind farms.
Suitable Deep Water Depths: Ideal ports for redevelopment have existing deep-water coastal facilities with access to open nearshore land, as they can easily be converted to support offshore wind energy. Ports that lack suitable deep water will need extensive dredging, requiring permits from federal regulatory agencies (e.g., the U.S. Army Corps of Engineers) and states; these permits are necessary for any work, including construction and dredging, in the nation’s navigable waters. Non-deep water ports being identified for deep water applications will need to be issued a license by the Maritime Administration on behalf of the Secretary of Transportation. The certification process is a joint effort performed by state and federal authorities, and the ports will need to meet a number of criteria before a license can be issued.
Contamination – a Legacy of Urban Areas: Many offshore wind energy farms are constructed near densely populated areas, for efficient electricity transmission. But many ports near urban and industrialized areas have a legacy of contaminated sediment from various nearshore historical property uses. Thus, contaminated sediments will be found at a majority of port facilities proposed for redevelopment.
Dredging required to accommodate offshore wind vessels also requires management of the dredged contaminated sediment. However, with proper management of these materials, beneficial use can provide a multifaceted solution to the challenges of managing waste materials commonly removed during port redevelopment to support offshore wind energy.
Construction, installation, and maintenance of offshore wind energy projects requires dedicated ports and vessels near densely populated areas.
Ports for the Future: It is important to take advancements in offshore wind technology into strong consideration while planning and analyzing port re-design requirements. Further developments of offshore wind megaprojects around the world are forcing manufacturers to scale up power output, lower costs, and increase efficiency—all of which leads to an increase in wind turbine size and ancillary assets such as offshore substations and HVDC (high-voltage direct current) converter stations.
Floating wind is also an advancement that cannot be ignored while assessing port requirements, primarily in areas where water depths are too deep for fixed-bottom solutions. The floating structures will require a variance in port designs when compared to ports being built for fixed-bottom turbines. Dry docks and berthing for the floating structures are examples of differences between a port designed for floating wind. It becomes even more of a challenge if the port is being used for both floating and fixed-bottom offshore wind developments. Ultimately, ports need to be designed in a way that allows flexibility to accommodate advancements in offshore wind technology.
Port Redevelopment Creates Green Opportunities
Port redevelopment also poses another opportunity to productively use multiple natural resources, in addition to beneficial use. Port facilities, particularly older facilities, can produce air, noise, and stormwater pollution. Redeveloping and rehabilitating older port facilities to support offshore wind provides an opportunity to modernize outmoded infrastructure with upgraded green infrastructure. Including solar power, low lighting, and smart stormwater as part of redevelopment helps ports comply with today’s environmental requirements. Most importantly, while port redevelopment requires a major shift in design approach, advancing port infrastructure ventures to support offshore wind energy provides multiple environmental, economic, and social benefits to the surrounding community.