Illustration of marine energy generators. Source: Green City Times.
Marine energy generators use technology designed to harness renewable energy from the ocean and other bodies of water. Energy can be generated from waves, tides, and currents as well as temperature and salinity differences between freshwater and seawater. While offering significant benefits as a renewable energy source, marine energy can have both positive and negative effects on conservation. Let’s go deeper on this subject.
What is marine energy?
Marine energy is energy generated from the natural movement of water. This is most often associated with the ocean, but there are examples and adaptations of use in lakes and rivers.
There are many types of marine energy generators. Wave energy generators capture energy from surface waves on the ocean and large lakes. Tidal energy generators harness energy from the rise and fall of tides and tidal currents in oceans, lakes, and large rivers. Ocean current energy generators utilize the kinetic energy of continuous ocean currents, like the Gulf Stream. Ocean thermal energy conversion (OTEC) exploits temperature differences between warm surface water and cold deep water. Salinity gradient energy generators harness energy from the salinity difference between seawater and freshwater. Hydrokinetic river turbines adapt tidal stream technology for non-oceanic fast-flowing rivers. These technologies can be combined with each other and with wind to improve efficiency and output. Each type of marine energy generator is suited to specific environments and conditions, and many are still under development to optimize efficiency, cost-effectiveness, and environmental compatibility.
Some notable real-world marine energy installations are the European Marine Energy Centre (EMEC) and The Rance Tidal Power Station. Based in Orkney, Scotland, EMEC hosts various wave and tidal energy devices for testing and demonstration. Established in 2003, EMEC helps reduce the time, cost, and risk of testing marine energy technologies. The Rance Tidal Power Station is a tidal power station located on the estuary of the Rance River in Brittany, France. Opened in 1966 as the world’s first tidal power station, the 240-megawatt facility is also considered a tourist attraction.
A couple of marine energy projects closer to Illinois are a wave energy project being done in Lake Michigan and a hydrokinetic project in the Lower Mississippi River.
The Lake Michigan project involves coastal communities partnering with a multidisciplinary research team to determine the best way to harvest wave energy at Beaver Island, Michigan and Nags Head, North Carolina. The project is being led by the University of Michigan and is researching the use of several technologies including wave buoy turbines.
A wave buoy turbine is a type of wave energy converter that generates electricity by harnessing the motion of ocean or lake waves. These systems are often compact, floating devices designed for easy deployment. Wave buoy turbines convert the mechanical energy from the vertical and horizontal movement of waves into electrical energy. They have the advantages of being scalable, having a low visual impact, and are renewable and predictable. But there are the challenges of withstanding the harsh conditions of the marine environment, the potential impact on marine life, and the high initial costs.
Inside the University of Michigan’s Marine Hydrodynamics Laboratory, Lei Zuo, the Herbert C. Sadler Collegiate Professor of Engineering and a professor of naval architecture and marine engineering, inspects a prototype buoy that generates electricity from wave motion. Whenever the buoy bobs up or down, the light blinks on. Image credit: Marcin Szczepanski, Michigan Engineering.
In the Lower Mississippi River, U.S.-based marine energy technology developer ORPC and Shell Technology – Marine Renewable Program are in the early stages of a project to deploy hydrokinetic turbines.
Hydrokinetic turbines convert the kinetic energy of moving water – such as river currents, tidal flows, or ocean currents – into mechanical energy, which is then converted into electrical energy. This technology has the advantages of not needing dams or reservoirs, utilization of a reliable energy source, scalability, and low visual impact. On the other hand, there are the challenges of biofouling (marine organisms can accumulate on turbine surfaces, reducing efficiency), potential negative impact on marine life, and high initial costs.
This project is taking advantage of the successful work done in Maine’s Millinocket Stream where a hydrokinetic power system was deployed underwater.
Hydrokinetic energy turbine that was deployed underwater in the Maine’s Millinocket Stream. Image Courtesy of ORPC.
Hydrokinetic power system deployed in Maine’s Millinocket Stream. Image Courtesy of US DOE. Buoys mark the device’s location.
The core technology, the Turbine Generator Unit (TGU), is designed to be modular and adaptable to various site conditions and end uses. In the Mississippi River that could be TGUs on piles, barges, and/or tethered mid-water column. Factors such as water depths, navigational traffic, environmental sensitivities, and stakeholder feedback are all taken into consideration to make sure the projects are sited appropriately. Maybe someday, these could be installed in the Fox River.
What does this ultimately mean for conservation?
Marine energy presents unique challenges and opportunities as a renewable energy source. The challenges are high costs and technological maturity (e.g., the two projects previously mentioned are still developmental and in the demonstration stage), the risk of environmental impact, regulatory and permitting hurdles, integration with current energy infrastructure, maintenance, and variability of energy sources. The opportunities are the use of a renewable resource, climate change mitigation, energy security and local benefits (such as job creation), innovation and technology advancement, and environmental benefits.
Marine energy, while offering significant benefits as a renewable energy source, can have both positive and negative effects on conservation. The impact depends on the type of marine energy technology, its location, and how it is implemented. Positive effects are reduction in greenhouse gas emissions, support for marine protected areas, reduced land use impact, and promotion of sustainable development. Negative effects are habitat disturbance, collision and entanglement risks (marine animals, particularly large fish, sea turtles, and marine mammals, may collide with or become entangled in underwater turbines and other infrastructure), the potential for changes in water flow and sediment transport, acoustic pollution, and the potential for chemical leaks due to leakage of lubricants.
These negative effects can be mitigated using comprehensive environmental impact assessments, avoiding installation in sensitive habitats and areas critical for biodiversity, wildlife-friendly designs, robust monitoring of operations and timely adjustments, and collaborations with conservation groups to ensure that projects align with broader conservation goals.
Marine energy has the potential to contribute to global renewable energy needs while also aligning with conservation goals, particularly when implemented responsibly. Striking the right balance requires collaboration among governments, developers, scientists, and conservationists to mitigate negative impacts and maximize benefits for ecosystems and communities.
The use of marine energy and conservation are different means of achieving common goals for addressing climate change. Conservation organizations can augment current electricity sources with marine energy for power, heating, and cooling of buildings and other facilities. Conservation organizations can promote the use of marine energy to help with air pollution, reduction of emissions, and climate change.
Ready to support conservation and a sustainable future? Well, that is what The Conservation Foundation does every day. We can all do more together than we can alone. To quote the Beach Boys, “Catch a wave and you’re sitting on top of the world.” Join our collective momentum – become a member today!
Feel free to comment on this blog with additional ideas you have on marine energy and conservation.
By Steve Stawarz, Oak Brook
DuPage County Advisory Council Member