Block Island and the National Offshore Wind Strategy

block island.jpg


In “Offshore Wind Project to Go Live as Industry Eyes Trump,” Bobby Magill reports in Climate Central:

In a few days, the water-bound wind turbines off of Rhode Island’s Block Island are expected to generate electricity commercially for the first time, and New Englanders are set to become the first in U.S. history to use electric power generated from an offshore wind turbine.

The Block Island Wind Project is the first commercial offshore wind farm ever built in the U.S., and the start of its operation marks the the beginning of a brand new clean energy industry in the United States.

Last year, Magill had reported that offshore wind was seen as a “missed opportunity” by scientists:

… the U.S. may be farther from large-scale offshore wind development than it was a decade ago partly because the federal government has not focused urgently enough on building renewables, a group of University of Delaware scientists says.

The government, through its offshore wind leasing program, is promoting offshore turbines for job growth and economic development rather than harnessing their most effective long-term potential — to tackle climate change, the scientists at the University of Delaware’s Center for Carbon-Free Power Integration wrote in a paper published … in the Proceedings of the National Academy of Sciences.

In September 2016 at the Wind Technology Testing Center in Boston, the Secretaries of Energy and the Interior released the National Offshore Wind Strategy, which was a  joint effort and the culmination of 18 months of collaboration between the two departments. This information is the most recent attempt at calculating the national wind energy potential.

The National Renewable Energy Laboratory developed four supporting technical reportsThis quantitative assessment incorporated new data to keep pace with advancing offshore wind technologies and applied technical, environmental, and competing-use exclusions to arrive the technical resource potential. The assessment considered the total amount of offshore wind energy to analyze the wind speed at the height where wind turbines operate—approximately 100 meters from the surface. Researchers first calculated how much kinetic energy was present in moving air currents, better known as wind, across the coastlines and Great Lakes. This estimate is the total offshore wind resource potential as seen below.


The U.S. Department of Energy’s Office of Renewable Energy and Energy Efficiency explains the multi-level process of determining how the the offshore wind energy potential is computed.

The next step is to calculate the gross resource potential by evaluating how much of the kinetic energy in the total offshore wind resource potential can be harvested using wind turbines of a specific size, arranged in a wind farm with a specified amount of space between turbines. For this resource assessment, we used a turbine hub height of 100 meters, which reflects projected technology development trends for U.S. offshore turbines in the next five years. We also assumed a capacity power density—a measure of how much electricity generating capacity the wind turbines have in a given area—of 3 megawatts (MW) per square kilometer, based on turbine spacing that U.S. offshore wind developers have proposed. We also assumed that all of the turbines would be within 200 nautical miles of shore, which coincides with the economic boundaries of the United States.

Analysts then combine these assumptions with estimates of how much power each wind turbine can capture. For example, the same turbine in a consistently windy area will capture more energy than a turbine in a less windy spot. Factoring this in yields what we call a “gross resource potential” of 10,800 gigawatts (GW) of capacity, or more than 44,000 terawatt-hours (TWh) of electricity generation per year.

44,000 TWh is a lot of energy! But realistically, we’re not going to put offshore wind turbines in every square kilometer of our oceans and Great Lakes. So, to refine the gross resource potential further to determine the technical resource potential, we first excluded areas that would not likely be developed because of current technology limits. For instance, we omitted all regions where the ocean is deeper than 1,000 meters because the systems for attaching floating offshore wind turbines to the seafloor are prohibitively expensive at those extreme depths. For the Great Lakes, we restricted the depth to 60 meters because offshore wind platforms in the freshwater Great Lakes will have the extra challenge of ice accumulation, and current floating technologies are not designed to withstand ice loading. Since projects are less likely to be economically viable where slow winds prevail, we excluded these areas as well. We also removed areas barred from energy development such as shipping lanes, wildlife refuges, and marine protected areas.

With these exclusions, U.S. offshore wind has a technical resource potential of more than 2,000 GW of capacity, or 7,200 TWh of generation per year. For context, this is nearly double the nation’s current electricity use. For comparison, approximately 90,000 homes can be powered by 1 TWh per year. This means that even if only 1% of the technical potential is recovered, nearly 6.5 million homes could be powered by offshore wind energy. According to the Wind Vision released by the Energy Department last year, developing just 86 GW, or about 4% of the U.S. offshore wind technical resource potential by 2050 would support 160,000 jobs, reduce power sector water consumption by 5%, and reduce America’s greenhouse gas emissions by 1.8%.



The cities and states can encourage renewable energy development, but the fate of federal support is uncertain as Climate Central reports.

The offshore wind industry is optimistic about the progress it has made in state legislatures, but because the industry is so dependent on the federal government for expansion, its future is uncertain. That uncertainty comes after a wave of progress made during the Obama administration.

“It’s really tough to know where things stand,” said John Rogers, a climate and energy analyst at the Union of Concerned Scientists. “It’s a wait-and-see time. We’re looking at what kind of team he’ll assemble. If (Trump is) serious about jobs, he can’t ignore offshore wind.”

Offshore wind is one of America’s largest untapped energy sources. As part of its strategy to reduce greenhouse gas emissions to prevent global warming from exceeding 2°C (3.6°F), the Obama administration unveiled a plan in September to build wind farms off of nearly every U.S. coastline by 2050 — enough turbines to generate zero-carbon electricity for more than 23 million homes.

None of that electricity is being generated today. Until now, the U.S. wind energy industry has watched European countries build offshore wind turbines by the thousands as efforts to build wind farms off the coast of the U.S. stalled.

Posted in

Nadia Ahmad

Leave a Reply