Many states are ramping up offshore wind goals and a state-by-state approach to transmission will mean higher costs for ratepayers, clean power advocates told Reuters Events.

“If each state goes it alone within a territory, it's going to be very expensive and a much slower process," said Kat Burnham, an analyst with Advanced Energy United that specialises on Connecticut, Massachusetts, and Rhode Island.

In New England, offshore wind developers are concerned about a lack of land connection points and slow grid approvals.

"We are in a bit of a bottleneck right now in terms of how long it takes for evaluation studies to be completed. This can impact project timelines, which has caused cost concerns," Burham said.

Like onshore wind and solar, offshore wind developers face delays in interconnection approvals as grid operators struggle to process a high number of applications and optimise the grid design for a clean power future.

Developers hope reforms agreed by the Federal Energy Regulatory Commission (FERC) will streamline interconnection approvals and reduce costs. The reforms call on grid operators to follow a first-ready-first-served cluster study process which should speed up processing and spread the cost between several projects. The Southwest Power Pool has shown that cluster studies can accelerate approvals and PJM plans to roll out the same process from 2026. Before then, PJM will look to reduce a backlog of applications that has created some of the highest interconnection costs in the U.S.

Last week, the federal government unveiled an action plan that calls for more collaboration among Atlantic Coast states to identify landing points for offshore wind and transmission paths on the outer continental shelf with the goal of building an offshore network of HVDC interlinks by 2050. Europe is already heading towards an offshore wind grid, starting with offshore interconnectors between countries.

Regional grid operators support the move, saying they are looking for "opportunities for increased interconnectivity, including for offshore wind, between our regions.”

A more bottom-up approach to transmission planning would allocate costs more efficiently since the new infrastructure will be shared by projects and regions, Burnham said.

A multi-value project (MVP) process for transmission investments may be more beneficial than a cluster process when assessing the wider region, Ammann said.

The MVP process assesses the transmission needs for a wide region going forward and divides the costs between all stakeholders that benefit. The process is already in use by regional grid operator MISO in Central US.

"By enabling a multi value procurement process across states, you're able to [find] streamlined processes, savings on costs and ultimately saving money for rate payers,” Burnham said.

Burnham is optimistic that efforts to increase coordination among state agencies, regional transmission organizations, and other stakeholders will ultimately lead to more interregional transmission planning.

"My hope is that by streamlining some efforts and offering transparency to information, we will be able to cut down on some of those project development timelines and save costs,” she said.