Some US electric grid operators, such as the Electric Reliability Council of Texas Inc., have pursued the notion that if they build transmission, generators will come.
But in the budding U.S. offshore wind industry, the opposite is now true: States are accepting proposals from developers that bundle generation and transmission together, creating a patchwork of proposals to deliver wind-generated power from offshore to a limited number of onshore interconnections. As the East Coast braces for up to 30 GW of offshore wind development by 2035, there has been limited coordination among the federal government, states and grid operators on the thorny transmission issue.
The Business Network for Offshore Wind on Oct. 26 released a white paper that called the lack of coordinated transmission policy "an existential constraint upon the ability of the OSW industry to reach its full potential in the U.S. market."
The trade group released the study the day before a scheduled Federal Energy Regulatory Commission technical conference to explore whether existing policies can accommodate future offshore wind growth.
The white paper recommends that policymakers, regulators and grid operators engage in long-term, inter-regional planning that quantifies all benefits and public policies set out by states, such as renewable energy standards.
"While there is debate about the optimal configuration of offshore transmission and the onshore grid upgrades necessary to integrate it, a planned transmission strategy is almost always ultimately more efficient than an unplanned, project-by-project approach," the study said.
More than 52 GW of proposed offshore wind interconnections are in the queues for the PJM Interconnection, New York ISO and ISO New England, according to the study.
A centralized transmission planning process in which grid operators evaluate all interconnection proposals at once — instead of sequential evaluation of individual proposals — is likely to yield a better transmission investment for both offshore transmission and the onshore grid upgrades necessary to integrate the new power sources, according to the study.
Two approaches
In the generator tie-in model, each wind farm connects its own transmission cables to an onshore interconnection point.
"The principal advantage of tie-line transmission configurations is the simplicity and speed at which offshore wind developers can move their project forward, without having to wait for other projects or larger transmission plans," the study said.
In a shared network transmission model, several generators connect to land through one or more shared offshore substations and export cables.
In the U.K., the white paper noted, an effort is underway to develop a more coordinated approach to offshore transmission planning. The Office of Gas and Electricity Markets said that constructing individual point-to-point connections for each offshore wind farm "may not provide the most efficient approach to could become a major barrier to delivery," preventing the U.K. from reaching its goal of 40 GW of offshore wind by 2030. A study showed a planned network could save up to ￡6 billion by 2050.
Current proposals
Anbaric Development Partners LLC has proposed to develop an open-access transmission network that could connect multiple offshore wind generators to a network of independently built cables. But the PJM Interconnection said the merchant transmission developer must have an offshore wind generator as a partner to build transmission lines. FERC denied Anbaric's complaint against PJM over the issue, and the company has appealed in court.
For the proposed 800-MW Vineyard Offshore Wind Project, developers Avangrid Inc. subsidiary Avangrid Renewables LLC and Copenhagen Infrastructure Partners K/S proposed to build two 220-kV export cables, buried up to eight feet below the seafloor, that would make landfall in either Barnstable, Mass., or Yarmouth, Mass., through the Muskeget Channel. The maximum length for the two cables combined would be 98 miles. The project could be the first utility-scale offshore wind farm in federal waters if approved by the U.S. Bureau of Ocean Energy Management in December. Avangrid is a subsidiary of Iberdrola SA.
BOEM's supplemental environmental impact study of that project, as well as the buildout of up to 22 GW of offshore wind on the Eastern Seaboard, said that, "BOEM assumes that each project would have its own submarine transmission line and that regional transmission right-of-way projects are not currently foreseeable." It did not address potential solutions to the lack of transmission interconnection points.
"Infrastructure does not currently exist to handle interconnection points and transmission for 22 GW of Atlantic offshore wind energy," the report said.
