The US offshore wind (OSW) sector is poised to play an important role in achieving energy transition and improving power system resilience. The country aims to achieve 30 GW of OSW by 2030 and 110 GW by 2050, with the Atlantic coast expected to be the primary contributor to these goals. The region hosts the country’s first 42 MW OSW installed capacity, while two commercial-scale projects aggregating 932 MW are under construction. Two additional projects (totalling 1.8 GW) have received federal approval to begin construction, and reviews of at least 16 OSW project plans, aggregating 27 GW, are expected to be completed by 2025. Further, state-level policies are driving the project pipeline of over 40 GW on the Atlantic coast. Substantial investment is required in offshore wind transmission (OWT) systems to connect wind farms, several of which are expected to be located 10 miles or more from the shore. This will allow the delivery of power further inland, connecting to high voltage facilities capable of integrating large volumes of OSW energy.
Proactive and coordinated interregional transmission planning is urgently required to facilitate OSW development. This would minimise the environmental impacts associated with cable route development and onshore upgrades, accelerate the timelines associated with permitting decisions and construction, and lower costs by providing increased capacity and stability to the grid. To deliver these, the US Department of Energy’s (DOE) Grid Deployment Office and Wind Energy Technologies Office (WETO), and the US Department of the Interior’s Bureau of Ocean Energy Management (BOEM) jointly released “An Action Plan for Offshore Wind Transmission Development in the U.S. Atlantic Region”. It comprises a set of bold actions to catalyse OSW energy and strengthen the domestic supply chain. This includes immediate actions necessary to connect the first generation of Atlantic OSW projects to the grid, and longer-term efforts to build the requisite transmission system.
The DOE also launched the Tribal Nation Technical Assistance Programme for OWT, partly funded by the Inflation Reduction Act, offering education and training resources to support engagement in OSW planning. Collectively, these actions will advance equitable and sustainable OSW development, domestic manufacturing and grid integration.
The Action Plan was developed through a series of Atlantic coast scoping conversations conducted by the DOE and BOEM. Additionally, the DOE’s Atlantic Offshore Wind Transmission Literature Review and Gaps Analysis, the ongoing Atlantic Offshore Wind Transmission Study (AOSWTS), which will be released by WETO by the end of 2023, and a series of convening workshops hosted from April 2022 to March 2023, have contributed to its formulation.
The preliminary results of the AOSWTS indicate that while radial generator lead lines and radial shared lines will be necessary for OSW deployment along the Atlantic, the DOE and BOEM recommend further reliability studies to be conducted on four interregional multi-terminal high voltage direct current (MT-HVDC) interlinks. Further, these meshed interlinks have been designed to take advantage of opportunities to maximise generation cost savings while minimising overall cable distances. Given the complexity of this transmission build-out from a technological standpoint and the need for extensive planning and coordination, several recommendations in the Action Plan are driven by the need for such lines and the expected timelines to develop them.
The recommendations for OWT build-out in the Action Plan are grouped into four time frames – immediate actions (before 2025); near-term actions (2025-30); mid-term actions (2030-40); and sustained actions. Further, these are organised into five categories – partnerships and collaborations; planning and operations; technologies and standardisation; economics and support initiatives; and siting and permitting. A criticality rating has been assigned to differentiate recommendations based on their potential to enable coordinated OWT development, with three stars for critical path actions, two for recommended action and one for best practice.
- Immediate actions: By 2025, the most critical actions involve establishing collaborative bodies across the Atlantic coast region; clarifying some building blocks of transmission planning, such as identifying points of interconnection and the North American Electric Reliability Corporation Reliability Standards for OWT; and addressing costs through voluntary cost assignments. Further, standardisation and research and development in the technology and environmental space, support for a growing supply chain and workforce, and siting and permitting improvements are some other critical works that need to be completed before 2025.
- Near-term actions: The near-term actions involve simultaneous convening and coordination – states collaborating to plan for an offshore network; the industry collaborating to standardise HVDC technology requirements; and federal agencies, tribal nations and stakeholders collaborating to identify and prioritise transmission routes on the outer continental shelf. Other key recommendations focus on providing regulatory guidance and data to decision-making entities, securing right-of-way from BOEM for preferred routes, and ensuring collaboration among states on clean energy standards and OSW goals. This will help develop transmission design solutions that maximise benefits for the entire region, including the marine environment and ocean co-users. Additionally, queue reforms for streamlining interconnection procedures and greater collaboration between developers and local communities are recommended as ongoing activities and practices.
- Mid-term actions: During the years up to 2040, there will be construction of interregional OWT along with the development of ambitious multi-state projects, setting a precedent for reaching the country’s long-term goals. Further, a national HVDC testing and certification centre will must be established to ensure compatibility with the new MT-HVDC networks being built. Further, updates to transmission planning need to be codified through regulated interregional joint planning, transfer capacity minimums, and market monitoring. Planning for the retirement and repurposing of OWT assets should also commence to ensure enduring value for the system in the coming decades.
- Sustained actions: The sustained actions involve improved environmental review and permitting frameworks, strong state leadership, empowerment of permitting agencies, and considerate cost allocation practices, as well as the utilisation of the national interest electric transmission corridors. Additional supporting actions focus on maximising the use of existing infrastructure and resources, including communication and information sharing, the use of grid-enhancing technologies to maximise the existing onshore grid capacity, and considering the utilisation of federal lands. Furthermore, there will be a focus on benefit valuation practices, ratepayer equity, and consumer advocacy to ensure that the substantial value of OSW and a holistically planned OWT grid is delivered back to local communities.
The DOE and BOEM have published the Action Plan as an interim publication to provide stakeholders with initial recommendations as well as solicit additional input on OWT development challenges and the identified potential solutions. The plan is expected to be revised and republished in 2024 after the completion of the AOSWTS. The US is pursuing an ambitious OSW programme, which requires proper planning, buy-in from all stakeholders, and the building of a robust supply chain, port infrastructure and a resilient transmission grid.