OCEAN
ENERGY
SYSTEM
LORONO | LUNA | TANDOY
Introduction
The ocean is one of the largest sources of renewable energy,
offering immense potential to support the global transition toward
sustainable energy. Ocean renewable energy technologies harness
natural oceanic forces, such as tides, waves, thermal gradients, and
salinity differences, to generate electricity. Additionally, energy
storage systems in the ocean play a crucial role in stabilizing and
optimizing power output from these sources. Civil engineers play a
significant role in designing, constructing, and maintaining the
infrastructure needed to harness and distribute ocean energy
effectively.
Four Types of Ocean Energy
1. Tidal Energy
2. Wave Energy
The tidal energy occurs every 12
hours due to the gravitational force
of the moon. The difference in
water height from low tide and
high tide is potential energy.
Wave energy is generated by the
movement of a device either
floating on the surface of the ocean
or moored to the ocean floor.
Four Types of Ocean Energy
3. Ocean Thermal Energy
Conversion (OTEC)
4. Salinity
Gradient Power
Ocean thermal energy conversion,
or OTEC, uses ocean temperature
differences from the surface to
depths lower than 1,000 meters, to
extract energy.
Salinity gradient power, also called
“blue energy,” harnesses the
chemical
potential
difference
between freshwater and seawater
to generate electricity.
1. Tidal Energy Systems
Tidal Barrages – Dams built across
estuaries to trap water at high tide and
release it through turbines at low tide.
Tidal Stream Turbines – Underwater
turbines that capture kinetic energy from
moving tidal currents.
Dynamic Tidal Power (DTP) – Uses long
barriers to channel tidal flows, creating
pressure differences that generate
electricity.
Function: Converts the movement of tides
into mechanical energy, which is then
transformed into electricity.
Parts and Functions
of Ocean Renewable
Energy Systems
2. Wave Energy Systems
Oscillating Water Columns (OWC) – A
chamber where rising and falling water
levels push air through a turbine.
Point Absorbers – Buoy-like structures
that move with waves, generating power
through hydraulic or mechanical systems.
Attenuators – Long floating structures
that flex with wave motion to drive
hydraulic pumps or turbines.
Function: Captures energy from ocean waves
and converts it into mechanical or electrical
energy.
Parts and Functions
of Ocean Renewable
Energy Systems
3. Ocean Thermal Energy
Conversion (OTEC) Systems
Heat Exchanger – Transfers heat from
warm surface water to a working fluid
(e.g., ammonia) that evaporates.
Turbine Generator – The vaporized
working fluid expands and drives a
turbine to generate electricity.
Cold Water Pipe – Pumps deep cold
seawater to condense the working fluid
back into a liquid.
Function: Uses the temperature difference
between warm surface water and cold deep
water to generate electricity.
Parts and Functions
of Ocean Renewable
Energy Systems
4. Salinity Gradient
Power Systems
Pressure
Retarded
Osmosis
(PRO)
Membranes – Separates seawater and
freshwater, allowing water to pass
through and create pressure.
Reverse Electrodialysis (RED) Stack – Uses
ion-selective membranes to generate an
electric current from salt concentration
differences.
Function: Generates energy by utilizing the
natural mixing of freshwater and seawater.
Parts and Functions
of Ocean Renewable
Energy Systems
Parts and Functions of
Ocean Energy Storage
Systems (ESS)
1. Underwater Compressed Air
Energy Storage (UW-CAES)
Compressor – Converts excess electricity into compressed air,
stored in deep-sea chambers.
Storage Chambers – Holds compressed air under high
pressure.
Turbine Generator – Expands stored air to drive turbines and
generate electricity.
Function: Stores excess energy by compressing air underwater
and releases it to generate power when needed.
Parts and Functions of
Ocean Energy Storage
Systems (ESS)
2. Gravity-Based Energy Storage
Lifting Mechanism – Uses electricity to lift heavy weights off
the seabed.
Weighted Structure – Large solid masses that store
gravitational potential energy.
Generator System – Converts kinetic energy into electricity
when the weights descend.
Function: Stores energy by lifting weights and generates power
when they are lowered.
Parts and Functions of
Ocean Energy Storage
Systems (ESS)
3. Seawater Battery Systems
Electrolyte (Seawater) – Acts as the conductive medium for
energy storage.
Electrodes – Facilitate the chemical reaction for charge and
discharge cycles.
Battery Cell – Stores and releases electricity as needed.
Function: Uses seawater as an electrolyte for large-scale and ecofriendly energy storage.
Integration of Ocean
Renewable Energy in
Civil Engineering
1. Coastal and Offshore
Structures
Tidal Barrages and Dams
Civil engineers design and construct tidal energy dams
and barrages, ensuring they withstand strong ocean
currents and environmental conditions.
Offshore Wind and Wave Energy Platforms
Engineers design stable platforms for offshore wind
and wave energy farms, integrating them with marine
ecosystems.
Seawalls with Integrated Energy Harvesting
Coastal defenses can incorporate wave energy
converters to generate electricity while protecting
shorelines.
Integration of Ocean
Renewable Energy in
Civil Engineering
2. Ports and Marine
Infrastructure
Sustainable Ports
Ports can integrate tidal and wave energy systems to
power operations, reducing reliance on fossil fuels.
Floating Energy Storage Stations
Civil engineers design offshore platforms that store
and distribute ocean-generated energy.
Wave Energy-Integrated Breakwaters
Civil engineers can design breakwaters (structures
protecting coasts from waves) to incorporate wave
energy converters (WECs).
Integration of Ocean
Renewable Energy in
Civil Engineering
3. Smart Cities and
Sustainable Urban
Planning
Hybrid Energy Grids
Ocean energy can be incorporated into urban power
grids, providing a clean and reliable electricity source.
Desalination Plants
OTEC and salinity gradient power can be used to
power desalination plants, providing fresh water for
cities.
OTEC for Cooling Systems
OTEC systems use deep-sea cold water to provide air
conditioning and cooling in urban buildings.
Challenges in Civil
Engineering Integration
Structural Durability
Environmental Impact
High Initial Costs
Marine environments cause corrosion
and material degradation, requiring
advanced construction techniques.
Coastal developments must balance
energy production with ecological
preservation.
Ocean energy infrastructure requires
significant investment and careful
planning.
Future
Opportunities
Floating Cities
Multi-Use Offshore Platforms
Sustainable Bridges and Tunnels
Future coastal urban planning could
integrate ocean energy for self-sustaining
floating communities.
Combining ocean energy generation with
aquaculture, tourism, and research
stations.
Bridges and tunnels could be designed
with tidal or wave energy generation
systems.
Conclusion
Ocean renewable energy presents an exciting opportunity for
civil engineers to develop sustainable and resilient infrastructure.
By integrating energy systems with coastal developments, cities
can harness clean energy while enhancing environmental
protection. While challenges such as high infrastructure costs,
environmental concerns, and technological development remain,
continued research and investment can drive widespread
adoption. With innovation, ocean energy can play a vital role in the
global renewable energy transition.
References
International Renewable Energy Agency (IRENA).
(2023). Renewable Energy Technologies: Ocean
Energy.
U.S. Department of Energy (DOE). (2023). Marine
and Hydrokinetic Energy Research & Development.
Ocean Energy Systems (OES). (2023). Annual
Report on Ocean Energy Developments.
European Marine Energy Centre (EMEC). (2023).
Wave and Tidal Energy Test Sites.
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