🌊Tidal and Wave Energy Engineering Unit 12 – Site Selection for Tidal Energy Projects

Key Concepts and Terminology

• Tidal energy harnesses the power of ocean tides to generate electricity
• Tidal range refers to the vertical difference in water level between high and low tides
• Tidal current velocity measures the speed of water moving in and out of a tidal area
• Tidal barrage involves constructing a dam or barrier across a tidal estuary or bay
  • Captures potential energy from the difference in water levels on either side of the barrage
• Tidal stream generators extract kinetic energy from fast-moving tidal currents
  • Operate similarly to wind turbines but are placed underwater
• Tidal fences are vertical structures with embedded turbines that span across tidal channels
• Tidal lagoons are artificially enclosed areas of seawater that capture tidal energy
• Capacity factor represents the ratio of actual energy output to the maximum possible output over a given period

Factors Influencing Site Selection

• Tidal range and current velocity determine the available energy potential at a site
  • Higher tidal ranges and faster currents generally indicate greater energy potential
• Bathymetry, which refers to the underwater depth and topography, affects turbine placement and installation
• Seabed composition and stability are crucial for anchoring and supporting tidal energy devices
• Proximity to electrical grid infrastructure influences the ease and cost of connecting the tidal power plant to the grid
• Accessibility for construction, maintenance, and monitoring purposes is a key consideration
• Competing uses of the marine space, such as fishing, shipping, and recreational activities, must be taken into account
• Environmental sensitivity and the presence of protected marine species or habitats may restrict site suitability
• Local community acceptance and support play a role in the success of a tidal energy project

Assessment of Tidal Resources

• Tidal resource assessment involves quantifying the available tidal energy at a specific location
• Historical tidal data, including tidal range and current velocity measurements, are analyzed
• Numerical modeling techniques, such as hydrodynamic models, simulate tidal flows and predict energy potential
  • Models consider factors like bathymetry, coastline geometry, and tidal constituents
• In-situ measurements using acoustic Doppler current profilers (ADCPs) provide real-time data on tidal currents
• Remote sensing techniques, such as satellite altimetry, contribute to large-scale tidal resource mapping
• Resource assessment helps identify the most promising sites for tidal energy development
• Detailed site-specific assessments are conducted to refine energy yield estimates and inform project design

Environmental Impact Considerations

• Tidal energy projects can potentially impact marine ecosystems and biodiversity
• Changes in tidal flows and sediment transport patterns may alter habitats and species distribution
• Noise and vibrations generated by tidal turbines can affect marine mammals and fish
• Collision risks exist for marine animals, particularly diving birds and large marine mammals
• Electromagnetic fields from underwater cables may influence the behavior of sensitive species
• Visual impact and landscape alterations are considerations for nearshore tidal energy projects
• Cumulative effects of multiple tidal energy installations in a region need to be assessed
• Environmental monitoring programs are implemented to track and mitigate any adverse impacts

Technical Feasibility Analysis

• Technical feasibility assessment evaluates the engineering and technological aspects of a tidal energy project
• Site-specific conditions, such as tidal range, current velocity, and water depth, influence the choice of tidal energy technology
• Foundation design and installation methods depend on the seabed characteristics and environmental loads
• Turbine selection considers factors like efficiency, reliability, and compatibility with site conditions
• Grid connection and transmission infrastructure requirements are assessed
  • Includes evaluating the capacity and stability of the existing electrical grid
• Maintenance and accessibility plans are developed to ensure the long-term operation of the tidal energy system
• Pilot projects and demonstration sites help validate the performance and reliability of tidal energy technologies

Economic Viability Evaluation

• Economic viability assessment determines the financial feasibility of a tidal energy project
• Capital costs, including equipment, installation, and grid connection, are estimated
• Operation and maintenance costs over the project lifetime are considered
• Energy production estimates based on tidal resource assessment are used to calculate revenue potential
• Financial metrics, such as net present value (NPV) and levelized cost of energy (LCOE), are evaluated
  • LCOE represents the average cost per unit of electricity generated over the project lifetime
• Sensitivity analyses are conducted to assess the impact of uncertainties and risks on project economics
• Financing options, including government incentives and private investments, are explored
• Long-term power purchase agreements (PPAs) with utilities or off-takers can enhance economic viability

Regulatory and Legal Framework

• Tidal energy projects are subject to various regulatory and legal requirements
• Environmental impact assessments (EIAs) are mandatory to identify and mitigate potential environmental effects
• Permits and licenses from relevant authorities are required for construction and operation
  • May include leases for seabed usage and approvals for grid connection
• Maritime spatial planning frameworks allocate marine space and resolve conflicts among different users
• Stakeholder consultation and public participation processes ensure transparency and address concerns
• International maritime law and conventions, such as the United Nations Convention on the Law of the Sea (UNCLOS), provide guidance on the use of ocean resources
• Liability and insurance considerations are important to manage risks associated with tidal energy projects

Case Studies and Real-World Examples

• The Rance Tidal Power Station in France, operational since 1966, is the world's oldest tidal barrage project
  • Demonstrates the long-term reliability and performance of tidal energy technology
• The MeyGen Tidal Energy Project in Scotland is one of the largest tidal stream projects in operation
  • Uses an array of underwater turbines to generate electricity from strong tidal currents
• The Sihwa Lake Tidal Power Station in South Korea is the world's largest tidal power installation
  • Utilizes a tidal barrage across an artificial lake to generate electricity
• The Bay of Fundy in Canada has one of the highest tidal ranges in the world
  • Multiple tidal energy projects are being developed to harness this immense tidal resource
• The Roosevelt Island Tidal Energy (RITE) Project in New York, USA, demonstrates the potential for tidal energy in urban settings
  • Utilizes tidal turbines installed in the East River to power nearby communities
• These case studies provide valuable insights into the challenges, opportunities, and lessons learned in tidal energy development