Offshore wind industry calls for ‘bold action’ on offshore HVDC grids in US

DNV and its partners in a joint industry project (JIP) that is working to identify barriers to the use of HVDC transmission in the U.S. grid have published a letter containing guidelines for the U.S. states for the build-out of an offshore HVDC transmission network that would best support the country’s offshore wind targets.

The letter offers a set of recommendations and a timeline to build a fully functional offshore HVDC transmission network. The offshore HVDC grid is critical to achieving the Biden administration’s goal of bringing 30 GW of offshore wind capacity online by 2030, according to DNV and the JIP partners, which called for bold action from U.S. states on its build-out.

DNV launched the JIP with ten offshore wind and transmission developers in January. Members of the JIP are Atlantic Shores Offshore Wind, DNV, EDF Renewables, Equinor, Invenergy, National Grid Ventures, Ocean Winds, PPL TransLink WindGrid, RWE, Shell, and TotalEnergies.

The recommendations issued now are the result of the JIP’s first phase, which inventoried and prioritized key technical issues that hinder the timely and efficient use of HVDC transmission.

The guidelines recommend that agencies, governor’s offices, developers, HVDC equipment manufacturers, and service providers work together toward building an offshore transmission system that will unlock the full potential of offshore wind projects, meeting deadlines and budgetary constraints effectively.

“Most imperative is an urgent need for states to focus on procuring 320 kV HVDC symmetric monopoles without AC or DC interlinks. This strategy not only safeguards ongoing project success but also secures continued public backing for offshore wind development. Leveraging mature technology and a larger fleet of vessels for offshore converter station transportation and installation, this approach minimizes risks, providing immediate benefits to existing and upcoming offshore wind projects while bolstering public trust in the industry,” DNV states.

The JIP recommends a gradual build-up of infrastructure that considers the global HVDC equipment market and recent tenders and partnerships in Europe that are driving the market, with the phased approach intended to overcome current barriers and create a clear pathway to an offshore transmission network.

The JIP partners laid out short-, mid-, and long-term milestones for building an HVDC transmission network, starting with symmetric monopoles at 320 kV, leading to a fully functional, 525 kV HVDC network with DC interlinks.

“It is crucial to the success of the U.S. offshore wind industry that state agencies and governor’s offices pay greater attention to market constraints and the evolution of offshore transmission technology,” said Richard S. Barnes, region president for Energy Systems North America at DNV.

“The recommendations outlined by this consortium [provide] a clear pathway to a reliable, flexible, and cost-effective HVDC transmission grid which will enable states to achieve their offshore wind energy goals.”