Abstract
Prepared as part of the Atlantic Canada Offshore Wind Grid Integration and Transmission Study led by Net Zero Atlantic, this Preliminary Transmission Expansion Needs Analysis to Integrate Offshore Wind in Atlantic Canada report provides a high‑level, preliminary assessment of transmission expansion needs to support the reliable integration of large‑scale offshore wind in Atlantic Canada by 2035 and 2050. The assessment also considers, at a high level, the transmission implications related to the potential development of energy‑intensive industries, such as hydrogen and its derivatives, as well as the potential for power exports beyond Atlantic Canada.
Based on current grid conditions and the assumptions applied in this preliminary analysis, the study indicates that Atlantic Canada could accommodate approximately 5–7.5 GW of offshore wind capacity by 2035 and 10–16.5 GW by 2050, subject to market conditions, policy choices, and the timing and scale of associated transmission grid investments. Higher offshore wind deployment levels—up to 7.5 GW by 2035 and 16.5 GW by 2050—were examined to evaluate transmission system performance under high development scenarios. Key findings and preliminary observations for each planning horizon are summarized below.
Significant Offshore Wind Potential Enabled by Strategic Grid Investment: By 2035, Atlantic Canada could integrate several large offshore wind projects, with total capacity on the order of 5-7.5 GW, provided that targeted transmission reinforcements are implemented. These investments are required to maintain system reliability and compliance with applicable North American Electric Reliability Corporation (NERC) and Northeast Power Coordinating Council (NPCC) criteria and to alleviate projected transmission bottlenecks that would otherwise constrain offshore wind integration. The assessment identifies priority transmission investments that increase the thermal capacity of the system and enable near-term offshore wind integration. Dynamic analyses indicate that additional stability-focused investments may be required to fully satisfy reliability criteria and would be identified through subsequent detailed studies.
Looking ahead to 2050, offshore wind deployment at higher levels (10-16.5 GW), combined with the emergence of large-scale hydrogen production and export markets, would require substantial expansion of regional transmission infrastructure. All Atlantic provinces would need additional transmission capacity and enhanced system flexibility to support reliable operation under these conditions. Strategic, coordinated grid investments are therefore a prerequisite for enabling higher offshore wind integration by 2050.
2035 Outlook — Near-Term Offshore Wind Integration: The 2035 preliminary assessment identifies priority transmission upgrades that would enable the reliable integration of 5-6 GW of offshore wind capacity while preserving system stability. These upgrades are focused on strengthening interprovincial ties and reinforcing key provincial transmission networks to improve power sharing and export capability across the region.
New Brunswick is identified as a critical interprovincial hub. Its grid—if appropriately reinforced—could transmit Nova Scotia’s surplus offshore wind power westward and support Prince Edward Island’s needs. Nova Scotia could integrate several gigawatts of offshore wind within its system by 2035, with additional capacity enabled through enhanced export capability and regional coordination. For Newfoundland and Labrador, a few large offshore projects (hundreds of MW) could connect locally by 2035, especially to supply on-island industry (e.g. green hydrogen in the Avalon Peninsula), but any significant exports off island would require new transmission corridors (for example, a second HVDC link between the island of Newfoundland and Nova Scotia).
Infrastructure investments complemented by operational measures and emerging technologies to maintain reliability as inverter-based generation increases in the systems across all provinces are required. With these combined actions, this preliminary study finds that Atlantic Canada could support its near-term offshore wind vision while maintaining compliance with reliability standards.
2050 Outlook – A Clean Energy Hub Requires Transformational Expansion: By mid-century, the offshore wind integration scenarios envision Atlantic Canada as a major clean energy hub, integrating 10 16+ GW of offshore wind and supplying domestic loads, robust export markets, and large-scale production of hydrogen and its derivatives. This would represent a threefold increase in offshore wind over 2035 and the emergence of a new multi-GW hydrogen industry or other large-scale industry. Achieving this outcome would require strategic and coordinated transmission expansion across the region to address system capacity and stability needs.
The 2050 analysis demonstrates that substantial offshore wind buildout could be enabled through strategic grid expansion. Targeted transmission investments are necessary to address thermal and stability constraints and support reliable integration across the region. To achieve this 2050 vision, every province’s transmission network must be strengthened ahead of the offshore wind deployments. While the infrastructure requirements for 2050 are significantly greater than those identified for 2035, they also represent an opportunity: early, strategic planning and investment could enable a fundamental transformation of the Atlantic Canadian power grid and unlock substantial offshore wind development.
Strategic Implications: With these actions, Atlantic Canada could become a leader in clean energy by harnessing its world-class offshore wind resource to decarbonize its own electricity supply and drive new industries and exports. The study recommendations align with utility roadmaps and net-zero policies1, but they also extend beyond business-as-usual. Achieving this vision would require unprecedented regional collaboration, including coordinated transmission planning, shared investment in interprovincial infrastructure, and alignment of operational practices across jurisdictions. This preliminary needs assessment also underscores the need for policy support to enable the timely construction of critical infrastructure and the integration of innovative technologies.
Recommended Next Steps: Once offshore wind locations, capacities, offtake markets, and development timelines are more clearly defined, detailed transmission planning studies2 would be required by each utility and system operator to further evaluate provincial‑level system impacts. The studies should assess injection levels, expansions and upgrade alternatives, loss of generation, and a more extensive set of contingencies. In parallel, stakeholder discussions with neighbouring system operators and planners regarding export integration should be initiated or continued, detailed engineering studies for proposed upgrades should be undertaken, and pilot projects (e.g. developing grid-forming inverter wind farms or large battery systems by 2030) should be considered to enhance overall system resilience.
This needs assessment provides a framework for preparing Atlantic Canada’s grid for initial offshore wind development and identifies pathways for the region to scale toward becoming a clean energy hub by 2050—delivering reliable, emissions-free power for domestic use, hydrogen production, and export markets. Advancing this vision would require coordinated action across the following key areas:
- Stakeholder Collaboration: Engage with neighboring jurisdictions, including ISO-NE and Hydro Québec, to explore coordinated export pathways and associated technical requirements. If Nova Scotia or New Brunswick anticipates exporting surplus offshore wind generation, initiating agreements and technical studies in the next few years will be important to support potential infrastructure development by 2035. Continued engagement with the Canadian Federal Government is also recommended to assess funding opportunities that align with broader economic development goals and decarbonization objectives.
- Policy and Regulatory Support: Collaborate with regulatory authorities to develop cost-recovery and cost-sharing frameworks that reflect the regional value of transmission investments delivering multi-provincial benefits. Interprovincial intertie infrastructure plays a key role in enhancing regional reliability, enabling clean energy integration, and supporting economic development. As such, coordinated regulatory approaches will be important to ensure alignment with broader regional planning objectives.