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7
The Practical Marine and
Hydrokinetic Resource Base
The Department of Energy (DOE) tasked the NRC to compare the
“potential extractable energy” from each of the marine and hydrokinetic
(MHK) resource assessments (see Chapter 1 for a discussion of termi-
nology and the statement of task). The task statement further directed
the study committee to review the methodologies and assumptions for
assessing the resources that might be practically available for energy
conversion and the potential limitations on these resources. Lacking a
standard set of definitions, the committee created a conceptual framework
of theoretical, technical, and practical resources for MHK in Chapter 1 (see
also the interim report, Appendix B). During discussions with each of the
resource assessment groups, the committee concluded that the groups
were assessing the theoretical resource, and some were attempting to
assess the technical resource. None of the assessment groups were tasked
directly with evaluating what the committee considers to be the practical
resource—the portion of the resource that is available for development
after taking into account technical capabilities; social, economic, regula-
tory, and environmental considerations; and alterations to the physical
environment. This is an issue of concern to the committee because these
filters will be critical for determining the MHK resource that could practi-
cally be expected to provide energy for generating electricity, as well as
for determining where future investments in MHK energy might be best
located. For many reasons, the site-specific and total practical MHK
resource is likely to be significantly less than estimates of theoretically
or technically available energy provided by the assessment groups.
76
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THE PRACTICAL MARINE AND HYDROKINETIC RESOURCE BASE 77
MOTIVATION FOR ASSESSMENT OF THE
PRACTICAL RESOURCE BASE
The objective of this chapter is to discuss the filters involved in deter-
mining the practical resource; how those filters impact the size and spatial
distribution of the practical resource; and how DOE might improve MHK
resource assessment and development. The committee observes that, as
with some other energy resources (see Box 1-3), the difference between
the theoretical or technical resource estimates and the practical resource
is large, making the practical resource small in a relative sense. While the
theoretical (or technical) MHK resource can appear substantial (many
tens of gigawatts or more), the practical resource tends to be small in
most locations or diffuse in nature. When considering small-scale energy
developments (typically less than 10 MW), MHK development may be
feasible and valuable in some locations, but utility-scale MHK develop-
ments (more than tens or hundreds of megawatts) will involve signifi-
cant infrastructure, can have substantial environmental impacts, and can
potentially conflict with other uses for the same area.
As an example, extracting 1 GW from waves approaching the Wash-
ington and Oregon coastlines would probably require the deployment of
a line of MHK devices extending at least 100 km parallel to and just off
the coast, which could have major impacts all along the coast. Similarly,
extracting more than a small fraction of the theoretical 9 GW resource
from Cook Inlet’s large tidal range and associated currents would prob-
ably require construction of a continuous fence of turbines that would
effectively act as a barrage, which could potentially be unacceptable for
societal and environmental reasons.
Determining the practical MHK resource will require a comprehensive
evaluation of how the resource interacts with social, environmental, regu-
latory, and economic filters. Some of the assessment groups have already
been moving to further evaluate the spatial variation, which has led to
selection of far fewer areas that could have potential for in-depth siting
studies and/or potential device installation. Part of the siting analysis
will include much more detailed modeling of backflow, circulation, and
other characteristics that are then calibrated and evaluated with field data.
The detailed siting studies are important, because the scale of impacts for
MHK development will probably be most significant at a site-specific or
local level. As plans progress for any MHK project, developers will need
to contend with two types of constraints: the impacts that it could have on
the physical and biological environment and the constraints of working in
an ocean or a river that has multiple uses and thus multiple management
objectives (e.g., social issues, spatial conflicts). These permitting-related
issues are in addition to the significant economic investments faced by
development of commercial-scale marine renewable energy.
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78 DOE’S MARINE AND HYDROKINETIC RESOURCE ASSESSMENTS
PRACTICAL CONSIDERATIONS FOR MHK DEVELOPMENT
The ocean, coast, and rivers support a number of established human
uses, as well as an expanding array of new uses. These include well-
established uses of the ocean, such as ports and harbors; commercial and
recreational fishing; traditional hunting, fishing, and gathering; com-
merce and transportation; oil and gas exploration and development; sand
and gravel mining; environmental and conservation activities; scientific
research and exploration; security, emergency response, and military readi-
ness; and tourism and recreational activities. The ocean also provides
cooling water for thermoelectric power plants that use coal, natural gas,
or nuclear fuel. In many cases, while the activity itself is well-established,
the intensity of use has been escalating. In addition, there are several new
or growing human use categories, such as aquaculture; maritime heritage
and archeology; and, of course, offshore renewable energy.
Each of the uses listed above comes with its own set of environ
mental, regulatory, social, and economic filters that have potential to
reduce MHK’s potential applicability at any given location. For MHK,
the committee identified a number of categories into which these filters
might fall (shown in the right-hand column of Figure 1-1). Examples of
each category are presented in Table 7-1, although it should be recognized
that some of the filters fall under more than one category. Because of the
large impact these filters have on the percentage of the resource that could
be practically available, they are explored in more detail in the following
sections.
Environmental Filters
MHK devices are likely to have a number of effects on the physical,
biological, and ecological environment of rivers and the ocean. These
environmental effects are in addition to the back effects addressed in
earlier chapters that are created by the MHK device or array and reduce
the available energy. Placing and operating the devices can have physi-
cal impacts on the subsurface, the water column, and the water surface
(e.g., alteration of the bottom substrate, scour and/or sediment buildup,
changes in wave or stream energy, turbulence, space taken up by devices
operating at the sea surface). When looking beyond the impact of one or a
few devices, large arrays of MHK devices could have significant effects on
the physical environment. It would be important to compare the impact
of an MHK array with the impact of other electricity generators having
the same average power output.
The dynamic nature of the devices (for example, moving blades on
turbines) has potential to lethally and/or behaviorally impact marine
mammals, fish, and diving birds. The relatively slow speeds at which
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THE PRACTICAL MARINE AND HYDROKINETIC RESOURCE BASE 79
TABLE 7-1 Examples of Filters That Could Impact the Development
of the Practical MHK Resource
Category Example
Environmental Impacts on marine species and ecosystems (e.g., nursery,
juvenile and spawning habitat, keystone species)
Bottom disturbance
Altered regional water movement
Regulatory Endangered Species Act
Coastal Zone Management Act
Marine Mammal Protection Act
Clean Water Act
Federal agency jurisdictions—for example, National Oceanic
and Atmospheric Administration (NOAA), U.S. Army
Corps of Engineers (USACE), Federal Energy Regulatory
Commission (FERC), State Department, U.S. Fish and
Wildlife Service (FWS), Environmental Protection Agency
(EPA), Bureau of Ocean Energy Management (BOEM),
U.S. Coast Guard
Social and economic Spatial conflicts (e.g., navigation, military operations, marine
sanctuaries, wildlife refuges, viewsheds, fisheries, tourism)
Interconnection to the power grid (e.g., transmission
requirements, integrating variable electricity output, shore
landings)
Capital and life-cycle costs (e.g., engineering, installation,
equipment, operation and maintenance, debris
management, and device recovery and removal)
the devices operate could minimize the effects of direct animal strikes
(Boehlert and Gill, 2010), but there are many other ways devices could
affect animals, such as altering migration pathways (e.g., upstream of
the device) or creating settlement surfaces for non-native species (as hap-
pens with oil rigs, for example). Some regions set aside for conservation
purposes might be off-limits entirely for MHK siting, while others might
have limited development in order to minimize impacts on sensitive
ecosystems. There are many other potential impacts related to acoustic,
chemical, temperature, and electromagnetic changes or emissions due
to MHK devices. However, it is also important to note that environ-
mental impacts related to MHK are likely to be mostly localized (within
k
ilometers of the devices), rather than spread over large areas, which will
make the impacts easier to assess spatially. This will also limit catastrophic
impacts due to failure of a device or array (unlike, for example, an oil or
gas well blowout).
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80 DOE’S MARINE AND HYDROKINETIC RESOURCE ASSESSMENTS
Regulatory Filters
There are a number of state and federal agencies with overlapping
jurisdiction for MHK power. Although FERC (an independent agency
within DOE) was granted jurisdiction over hydroelectric development
through the Federal Power Act, leases on the U.S. outer continental shelf
require approval by BOEM (Department of the Interior) according to the
Outer Continental Shelf Lands Act and the Energy Policy Act of 2005
(Righi, 2011). This is further complicated in the case of ocean hermal t
energy conversion (OTEC), because NOAA (Department of Commerce)
was given responsibility for licensing commercial OTEC facilities under
the Ocean Thermal Energy Conversion Act of 1980. Because no applica-
tions were received, in 1996 the regulations for licensing commercial
OTEC plants were rescinded. OTEC demonstration projects are not
required to receive a license but must instead be designated as a demon-
stration project by DOE.
FWS (Department of the Interior) and NOAA are charged with coor-
dinating activities to protect marine mammals from potentially harmful
development under both the Marine Mammal Protection Act of 1972
(16 U.S.C. § 31) and the Endangered Species Act (16 U.S.C. § 1531-1544).
NOAA also has jurisdiction under the Magnuson-Stevens Fisheries Act to
protect essential fish habitats (16 U.S.C. § 1855(b)(2)). Projects in navigable
waters typically fall under the jurisdiction of USACE under the Rivers
and Harbors Act but may also require involvement from the U.S. Coast
Guard (Righi, 2011). USACE permitting may also be required for any
projects involving dredging rivers or coastal areas under the Clean Water
Act (PNNL, 2010). The Coastal Zone Management Act involves coordi-
nation among local, state, and federal agencies to ensure that plans are
in accordance with a state’s own coastal management program (PNNL,
2010). In addition to dealing with federal authorities, offshore renewable
development in state waters will fall under state rules, with parts of the
system (e.g., the transmission cable on land) also subject to county and
municipal zoning.
A good example of the complexity of these jurisdictional issues is
from California, where, owing to the state’s own laws and regulations—
for example, California Organic Act, California Harbors and Naviga-
tion Code, and California Coastal Act)—the alifornia atural Resources
C N
Agency, the California Environmental Protection Agency, and the Cali-
fornia Public Utilities Commission were all involved in a memorandum
of understanding with FERC regarding the development of MHK off the
coast of California (CalEPA et al., 2010).1
1 The memorandum of understanding “seeks to develop a procedure for coordinated
and efficient review of proposed [marine and] hydrokinetic projects that is responsive to
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THE PRACTICAL MARINE AND HYDROKINETIC RESOURCE BASE 81
For electricity generation, most transmission-level interconnections
are governed by federal rules through FERC. However, siting of transmis-
sion and distribution lines is controlled by state and local governments.
This raises a number of jurisdictional problems for new generators. Even
when a specific MHK site is determined, appropriate resource assess-
ment will be governed by complex power regulations related specifically
to how any needed transmission is developed and how the generator is
connected to the grid.
Social and Economic Filters
Spatial Conflicts
Oceans and rivers are crucial resources for local communities, states
and regions, and the country as a whole. Navigable waters are a resource
for a number of sectors, and coordinating their use is an immense logis-
tical challenge that will definitely impact MHK energy development.
In the case of tidal power, some of the locations with the highest tidal
energy density are also estuaries having ports with heavy commercial
shipping traffic. It is likely that there will be limitations to the number
and size of turbines and the depth at which they can be deployed so as
not to interfere with established shipping lanes. In regions of the United
States with an active U.S. Navy presence, there may be constraints on
MHK siting owing to military operational, training, or security concerns.
Tourism and recreational traffic pose another spatial conflict—impeding
a popular bay with an array of turbines may affect not only recreational
fishing but also tourism. This is also true of commercial fisheries, which
could be unfavorably impacted if an MHK deployment restricts access to
desirable fishing grounds. Finally, existing structures may have to be con-
sidered. A site may become more or less advantageous because of existing
infrastructure—for example, while in-stream turbines may require limited
deployment near a bridge due to their potential impact on river scour, it
may be advantageous to deploy them in the discharge canals of power
plants. Such site-specific logistical constraints due to multiple uses of
rivers and the ocean are not adequately captured in a general technical
resource assessment.
The potential for multiple uses may reduce conflicts and create oppor-
tunities for meeting shared objectives. For example, offshore aquaculture
and MHK structures could be sited together, allowing them to jointly meet
environmental, economic, and cultural concerns, while providing a timely and predictable
means for developers of such projects to seek necessary state and federal approvals.” It
further delineates the eight state and local agencies with which the California parties will
coordinate in order to meet this objective.
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82 DOE’S MARINE AND HYDROKINETIC RESOURCE ASSESSMENTS
fish and energy production management objectives while creating few
spatial conflicts with other uses. It may also be economically beneficial to
these companies as they might all benefit from access to similar resources
for staging and maintenance of their structures.
Interconnection to the Electrical Grid
Even after a minimally conflicted site is found, there is still the issue
of how to extract the electricity and distribute it to customers. Electricity
is often generated at power plants or generators that may not be located
near the demand for it, which necessitates long-distance transmission. To
arrive at a true estimate of the costs of integrating an MHK installation
into the electrical grid of a local utility or regional transmission operator,
a number of factors would need to be considered, including the size of the
generator (e.g., the size of a tidal turbine array), the strength or weakness
of the overall electric system, reliability requirements for the generator
and the electricity system, proximity of the generator to the potential
interconnection, and configuration of the existing system. The local utility
or regional transmission operator will conduct interconnection studies as
required to determine the costs to interconnect with its existing electrical
grid. These costs will include costs for interconnection and the costs for
any required upgrades to the existing electrical grid to handle the addi-
tional generation from the MHK project. The process and costs for inter-
connection will vary depending on whether the device connects directly
to either the transmission or distribution system (Figure 7-1).
The electric power system is planned, constructed, and operated to
provide safe, highly reliable, and stable service to all customers, even
during severe disturbances. The reliability rules for a system consist of
requirements for resource adequacy, including generation reserve mar-
gins; transmission capability, including stability analysis; and emergency
operations (NYSRC, 2011). Bringing MHK energy onto the grid, then, is
complicated by many factors. Harsh environmental conditions, unstable
load flows, variable energy output, lack of electrical demand near the
generation, the length of cable from a device or array to a shore erminus,
t
potential environmental impacts from the cable, permitting issues, and
the need for specialized equipment for reactive power control are all
challenging. However, the penetration of gigawatt-scale wind energy into
the U.S. and European grid demonstrates that intermittent resources can
be brought online and can provide a model for integrating MHK energy
with traditional resources. It is unlikely that MHK resource variability
would be a destabilizing element for a given electricity system or that
it would require electricity storage technologies.
An offshore transmission system is needed to allow offshore genera-
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7-1
-
FIGURE 7-1 Basic structure of the electric system showing an MHK resource as the electricity generator connecting to the transmis-
sion system. For small-scale applications (<10 MW), the MHK generator will probably connect directly to the distribution system.
SOURCE: Adapted from U.S.-Canada Power System Outage Task Force, 2004.
83
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84 DOE’S MARINE AND HYDROKINETIC RESOURCE ASSESSMENTS
tors, whether wind or MHK, to transport the electricity generated to shore
and then to customers or utilities. The distance required to interconnect into
the electricity system is critical, as it directly impacts the economic viability
of a project. Additionally, the electricity from these generators then must
be integrated into the power system, where the temporal variability of the
resources might become important. The situation could be more compli-
cated if there are large numbers of offshore generators, because connecting
a large number of devices together with no load demand along the path
of the network cable could produce an unstable system. Another issue is
device and equipment reliability, discussed in the following section.
An important consideration for evaluating the practical MHK resource
base is how the location of a potential MHK resource compares with the
location of load centers that might utilize the resource. The overall attrac-
tiveness to coastal resources that has been identified in discussions and
planning for offshore wind on the U.S. East Coast is that the resource is
inherently close to major load centers. Close proximity to load centers can
increase the value of a resource by reducing the costs and siting issues
associated with the transmission requirements. In the case of offshore
wind generation, the higher costs of offshore vs. onshore wind generation
are to some extent offset by a higher local price environment that exists
on the East Coast and the reduced cost and siting issues associated with
locating transmission. Although a significant portion of wave, tidal, and
in-stream resources are located in rural Alaska, each of those three assess-
ment groups did mention other areas where the resources are located
close to population centers. As noted in the OTEC resource estimate,
most of the resources for U.S. territorial waters are in locations with low
population densities (Micronesia and Samoa). In general, OTEC faces the
challenge of utilizing power produced at sea far from demand centers.
Capital and Life-Cycle Costs
As with other energy devices or plants, there are costs associated with
the device itself and its design, installation, operation and maintenance,
and removal or replacement. The largest of these costs, and potentially
the greatest barrier to MHK deployments, is the capital cost. An earlier
NRC committee concluded that it will take at least 10 to 25 years before
the economic viability of MHK technologies for significant electricity pro-
duction will be known (NRC, 2010). A 2008 report evaluating the potential
for renewable electricity sources to meet California’s renewable electricity
standard found that the cost of electricity from waves and currents was
higher than that from most other renewable sources and had a substan-
tially greater range of uncertainty (Black and Veatch, 2008).
Once installed, MHK devices will be subject to mechanical wear and
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THE PRACTICAL MARINE AND HYDROKINETIC RESOURCE BASE 85
corrosion that is more severe than that experienced by land-based equip-
ment. Corrosion-related problems remain as key challenges for all MHK
devices. In addition to the general galvanic corrosion in marine environ-
ments, issues related to stress corrosion in both static and dynamic load-
ing environments, corrosion fatigue, biocorrosion, and marine fouling will
have to be addressed. Advanced structural materials with appropriate
coatings and paints will have to be identified in order to construct the
robust, corrosion-resistant components for MHK energy generation (Bahaj
and Myers, 2003; Hudson et al, 1980; Liu et al, 1999; Mueller and Baker,
2005). Some technology to address these challenges might be adapted
from mature industries like the defense and oil and gas sectors.
Design for survivability becomes another important consideration
for device siting, particularly in shallow water. Devices can be destroyed,
damaged, or moved from their moorings under the actions of rough
seas and breaking waves associated with 50- and 100-year storms that
can occur well within the 20- to 30-year life expectancy of the devices.
For example, stronger-than-expected currents in New York’s East River
caused Verdant Power’s turbine blades to fail only one day after installa-
tion in 2006 and led to redesigned blades. Using more rugged design cri-
teria for future MHK devices may drive up the product cost due to exotic
materials or increased engineering costs and could also delay deployment
until more robust designs are available in the market, all of which may
play a role in the cost of electricity generated from an MHK device in the
near term. In addition, power electronics on MHK devices will be a chal-
lenge to implement and operate reliably.
In addition to the hostile nature of the marine environment, there are
other challenges that affect the survivability and maintenance of MHK
systems. In shallow tidal and riverine areas, there is a great concern that
debris will affect both the efficiency and durability of any installed devices.
In Alaska, which is cited as a potentially large resource for development by
the in-stream assessment group, river freezing in the winter months and
scour incurred during spring ice break-up will make year-round deploy-
ment a challenge and may require seasonal device removal. These chal-
lenges affect not only installation and maintenance costs and electricity
output, but also MHK scalability from small to utility applications.
MULTIPLE-USE PLANNING FOR MARINE
AND RIVERINE ENVIRONMENTS
The basis of many of the critical social, economic, regulatory, and
environmental filters identified in previous sections is meeting multiple
management objectives from the shared coastal, ocean, and riverine envi-
ronment. With a growing number of uses, users, and demands, there are
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86 DOE’S MARINE AND HYDROKINETIC RESOURCE ASSESSMENTS
increasing spatial and regulatory conflicts in meeting these management
objectives. Planning for multiple uses can maximize the achievement of
multisector goals while reducing conflict. While these conflicts can be
perceived as having the potential to delay or deter future technology
development, Verdant Power’s Roosevelt Island Tidal Energy Project is an
example of a small-scale commercial deployment navigating these regula-
tory hurdles successfully, and more projects are likely to be forthcoming.
Furthermore, many of these filters are analogous to those faced by tradi-
tional power generation projects. With current rates of electricity usage,
society will have to choose among various options for power generation,
each with its own set of objectives, conflicts, and trade-offs.
MHK Siting
Offshore alternative energy, both wind and MHK, has been a primary
driver for the development of local and regional ocean planning in the
United States (e.g., Massachusetts, Rhode Island, Oregon, and the mid-
Atlantic region [OORMTF, 1991; MAEEA, 2009a, 2009b; MAGA, 2009;
RICRMC, 2010]). MHK theoretical and technical resource assessments
can help initiate a planning process that explicitly addresses and reduces
spatial conflicts with other users. Many other uses have much larger foot-
prints, impacts, and conflicts with one another but are often entrenched
uses with specific, single-objective management approaches (e.g., com-
mercial fisheries). Because offshore alternative energy represents a new
use of the environment and does not have an established management
approach at the state, regional, or national level, it will probably need
to fit with existing uses and users. Social and economic filters discussed
in the above sections are critical for identifying and reducing conflicts
between other uses and MHK siting.
As part of the DOE tidal resource assessment, Defne et al. (2011) illus-
trated how MHK resource data could be combined with socioeconomic
and environmental GIS layers to identify where MHK projects might be
sited (Table 7-2). They explicitly represented their analysis as an example
of how the data can be combined, and the committee found this was the
most advanced example by any group attempting to assess the practi-
cal resource. While still largely a single-objective rather than multiple-
objective analysis, the authors try to identify how one might place a MHK
project where the potential energy is great and conflicts are few.
As part of MHK site planning efforts, potential trade-offs increasingly
need to be explicitly identified and quantified, including market and non-
market values. For example, when deciding where to locate devices or
arrays, these valuations could be used to quantify positive and negative
impacts on multiple sectors such as fishing, shipping, whale watching,
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THE PRACTICAL MARINE AND HYDROKINETIC RESOURCE BASE 87
TABLE 7-2 GIS Layers Showing Environmental and Socioeconomic
Constraints Identified in the DOE Tidal Resource Assessment
Layer Theme Role
Environmental Fish Critical areas
constraints Invertebrates
Reptiles
Birds
Mammals
Plants and habitats
Socioeconomic Urbanized areas Favorable areas
constraints Transmission
Transportation
Built-up areas
Restricted areas Restricted areas
Fairways and shipping lanes
Dumping sites
Cable areas
Pipeline areas
Shoreline constructions
Wreck points
Mooring and warping points
Recreation areas and access locations
(boat ramps, diving sites, marinas)
Management areas
(marine sanctuaries, national parks, wildlife
refuges, special management areas)
Cultural heritage sites
(archaeological sites, historical sites)
Resource extraction sites Not assigned
(Aquaculture sites, commercial fisheries,
recreational fishing)
SOURCE: Adapted from Defne et al., 2011.
recreational sailing, scenic views, and rare species. Including these values
explicitly in the cost-benefit analysis may result in a different decision about
MHK sites than if only the energy sector is considered (NOAA, 2011b).
Tools for MHK Site Planning
While full trade-off analyses (including benefits and costs) have rarely
been used in ocean planning efforts to date, there are many decision
support tools that can help assess trade-offs. They can be analyzed with
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88 DOE’S MARINE AND HYDROKINETIC RESOURCE ASSESSMENTS
quantitative and qualitative methods (e.g., Barents Sea, Netherlands) or
with expert judgment (Wadden Sea). Where there has been prioritiza-
tion of spatial uses, trade-off analysis can avert incompatible uses (e.g.,
G
erman Exclusive Economic Zone) or permitting decisions (e.g., Shetland
Islands). They can also be used to compare alternative scenarios in order
to identify potential least-cost solutions (e.g., St. Kitts and Nevis, Belgium,
and California) (NOAA, 2011b).
One such spatially explicit decision support tool is MarinePlanner
(formerly MarineMap), which is used in California, Oregon, Washington,
and the mid-Atlantic region. This tool allows users to designate spatial
use zones and to estimate the benefits, costs, risks, and impacts of their
decisions. MarineMap and MarinePlanner were explicitly developed for
extensive stakeholder engagement as part of spatial planning (Gleason
et al., 2010). MarineMap is currently being used as part of Oregon efforts
to identify areas where wave energy could be feasibly sited with fewer
conflicts in an explicitly multiobjective context.2 After extensive engage-
�����������������������
ment with stakeholders and affected state agencies, policies, standards,
and procedures were created to approve new energy development.3 The
next stage will result in maps to guide the location of renewable energy
facilities while protecting areas that are important to ocean fisheries or are
essential marine habitat.
Another set of decision support tools used in alternative energy
development are the Prospector tools developed by the National Renew-
able Energy Laboratory (e.g., Solar Prospector, Geothermal Prospector).
These tools are designed to bring together critical information about
the resources and areas of concern in their development so that stake-
holders can identify where they might maximize benefits and minimize
conflicts. For example, stakeholders (including developers and environ-
mental groups) can assess with Solar Prospector where theoretical energy
resources (e.g., solar resources) are greatest and where conflicts may be
fewest (e.g., away from areas of environmental concern). Such tools can
be further improved to provide the most relevant information for MHK
resource development by engaging with stakeholders, as has been done,
for example, with MarinePlanner.
Approaches developed specifically for siting wind farms, based on
macro-siting and micro-siting optimization, could provide a methodologi-
cal template for optimizing MHK siting (Rhétore et al., 2011; Grilli et al.,
2012). These approaches seek to optimize device locations by considering
physical constraints (such as the complex aerodynamic wake effect behind
turbines) as well as socioeconomic and environmental constraints associ-
2 Available at http://oregon.marinemap.org/.
3 Available at http://www.oregon.gov/LCD/OCMP/Ocean_TSP.shtml.
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THE PRACTICAL MARINE AND HYDROKINETIC RESOURCE BASE 89
ated with ecosystem services (e.g., foundation and cable costs, commercial
and recreational fisheries costs, environmental cost). They are based on an
explicit cost optimization approach and extend the traditional optimiza-
tion of tangible costs to the intangible costs associated with the ecosys-
tem services constraints (Oumeraci et al., 2009). Such approaches were
recently applied in Denmark to the Middleground wind farm ( hétore R
et al., 2011) and in Rhode Island via the Special Area Management Plan
(Grilli et al., submitted 2012).
Incorporating MHK Resource Assessments into Ocean Planning
Each of the MHK resource assessments was required to create a GIS
database, and most have included information related to the theoretical
and technical resource identified in the assessment. Incorporating these
databases into the variety of existing spatial decision support tools allows
the MHK resource to be viewed in the context of other economic and
ecological uses, such as shipping channels or areas associated with criti-
cal habitats. This information would be helpful to prioritize research that
enables multiple uses and mitigates potential user conflicts, although it
would not be sufficient for quantifying the practical resource base.
CONCLUSIONS AND RECOMMENDATIONS
Site-specific analyses will be needed to identify the constraints and
trade-offs necessary to reach the practical resource. The site-specific,
practical MHK resource is likely to be substantially less than assess-
ment group estimates of the theoretical or technical resource. Although
theoretical and technical MHK resource assessments are useful for pri-
oritization and planning, site-specific filters will be needed for useful
estimates of the practical resource. This chapter lists a selection of con-
siderations that investors, developers, regulatory or permitting agencies,
and the public are likely to weigh in making decisions about MHK site
placement, permitting, and installation.
An estimate of the practical resource base and its geographical
distribution is necessary for determining the potential MHK contribu-
tion to U.S. electricity generation. GIS resources generated by the DOE
assessments, when completed, will assist stakeholders, investors, and
regulators best fit MHK energy development into the regional ocean or
riverine environment.
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90 DOE’S MARINE AND HYDROKINETIC RESOURCE ASSESSMENTS
Recommendation: DOE should ensure that spatial data resulting
from the MHK resource assessments is readily and publicly avail-
able for use in siting and permitting decisions.
DOE has already published data on the spatial distribution of the
theoretical energy resources and should continue to play an active role
in characterizing the resource base and in developing decision support
tools that can steer consideration toward areas that could be the most pro-
ductive and feasible for development. An accessible spatial database of
theoretical and technological MHK resources would provide substantial
information on high-priority sites.
