February 9, 2010
Maryland study finds huge potential for offshore wind
Offshore wind power holds the potential to meet Maryland's entire need for electricity.
Researchers at the University of Delaware's Center for Carbon-free Power Integration (CCPI) were contracted by the Abell Foundation to conduct a preliminary study of Maryland's offshore wind power potential. Only Maryland's oceanic waters were considered, not the potential for wind power in the Chesapeake Bay.
The results of this study indicate that Maryland's offshore wind resource is large enough to supply the state with 67 percent of its electric needs, even if using only existing offshore wind power technology. Offshore wind could provide 179 percent of its electric needs as the industry matures and deeper water technologies become commercialized. The resource is large enough to not only satisfy all of Maryland's demand for electricity, but part or all of the demand in neighboring inland states as well.
Maryland's legislature has passed a Renewable Energy Portfolio Standard (RPS) requiring Maryland utilities and competitive retail suppliers to obtain an increasing percentage of their electric power from renewable energy sources. By 2022, 22.5 percent of retail sales must be sourced from renewables, 18 percent of which can be from wind energy. The amount of capacity needed to fulfill the portion of Maryland's RPS which can be satisfied by offshore wind energy is 3,900 MW, or about three quarters of the available near?shore resource.
The study says that building out Maryland's offshore wind potential could benefit the state's economy for offshore construction, maintenance, supply chain, and/or turbine manufacturing. 1 Technical Summary
The study area was defined as Maryland's northern and southern land borders, extended due east in the ocean. Using bathymetric (water depth) data obtained from the NOAA) the study area was divided into four segments based on the turbine foundation technology most suitable within a particular depth range. The four depth segments were labeled by turbine foundation technology as follows: Monopile (0?35 m), Jacket (35?50 m), Advanced Jacket (50?100 m), and Floating (100?1,000 m). The study area did not go beyond 1,000 m to keep the results tied to existing offshore wind technologies; no existing turbines have been demonstrated beyond that depth.
Understanding the resource associated with each depth region, rather than just producing an estimate for the study area as a whole, provides insight into the timing and feasibility of building out the resource. For example, monopile technology has over fifteen years of operation experience in Europe and can be implemented today in the U.S. Jacket structures have been deployed on a limited basis and have only a couple of years of operational experience. Floating turbines are just now beginning prototyping and have years of testing and further development before they are available in the market.
For the purposes of the study, the available area for development was defined as that left after excluding conflicting ocean uses. This study identifies nautical exclusions by using NOAA nautical navigation charts and GIS software to accurately trace and map conflict areas such as artificial reefs and dump sites.
Shipping accounts for the largest potential conflict area and exclusion zone within the study area. There are no official shipping lanes, as identified by IMO, in Maryland's oceanic waters. As a result, the study does not categorically exclude any area on the basis of commercial shipping. However, because there nonetheless exists significant ship traffic in these waters as ships move in and out of the Delaware Bay and up and down the Atlantic seaboard, it identifies potential areas of conflict with commercial ship traffic.
The most prominent ecological conflict that offshore wind turbines pose is with respect to seabirds. To identify a reasonable conflict area for avian exclusion, the study relied on the advice of renowned ornithologist Paul Kerlinger, who advised exclusion of the area within one nautical mile (nm) of the shore. This area was recommended because it is within the Atlantic flyway for migratory bird species and fits with the behavior of migratory birds, which tend to hug the shoreline. Other potential ecological conflicts, such as the disruption of benthic organisms or marine mammals, were not included in the scope of this study.
The study incorporates an eight nautical mile visual exclusion zone for the entire coastline.
Through this process, it was determined that the area available for offshore wind development in Maryland up to 1,000 meters depth is 9,526 sq. km.
Though there are no IMO identified shipping lanes the study utilized the International Comprehensive Ocean?Atmosphere Data Set (ICOADS) to identify and map, potential conflict areas between heavy ship traffic and wind turbine placement. The total potential conflict area was estimated at 3,300 sq. km, still leaving 6,226 sq.km available for wind turbines.
Offshore Wind Power Potential and Energy Production
The wind power potential of the available area was calculated by combining (a) an analysis of the most accurate wind speed data available for the study area, (b) an offshore wind turbine power output model that estimates power generation from wind speed data, and (c) the spacing of turbines and therefore the number of turbines that could be installed per sq. km.
The study found that nearly 3,000 turbines could be installed within the 0?35 m depth zone, which on average could supply 67 percent of the Maryland electric load. Considering from 0 to 50 m depth, the study indicats that offshore wind has the potential to fulfill 133 percent of Maryland's load. If fully developed out to 1000 m depth, offshore wind power has the potential to generate over 179,000 Gigwatt? hours (GWh) per year.