Category Archives: Ocean Sciences

Floating Wave-powered Generators Offer the Potential for Commercial-scale Energy Harvesting From the Ocean

The idea of extracting energy from wave motion in the open ocean is not a new one. This energy source is renewable and relatively persistent in comparison to wind and solar power. However, no commercial-scale wave power generator currently is in operation anywhere in the world. The primary issues hindering deployment of this technology are:

  • the complexity of harnessing wave power
  • the long-term impact of the harsh ocean environment (storms, constant pounding from the sea, corrosive effects of salt water) on the generating equipment
  • the high cost of generating electricity from wave power relative to almost all other energy sources, including wind and solar

In April 2014, Dave Levitan posted an article entitled, “Why Wave Power Has Lagged Far Behind as Energy Source,” on the Environment360 website. You can read this article at the following link:

You’ll find a June 2014 presentation entitled, “Wave Energy Technology Brief,” by the International Renewable Energy Agency (IRENA) at the following link:

The general consensus seems to be that the wave energy industry is at about the same level of maturity as the wind and solar energy industries were about 30 years ago, in the 1980s.

Several U.S. firms offer autonomous floating devices that are capable of extracting energy from the motion of ocean waves and generating usable, persistent, renewable electric power. Two of the leaders in this field are Ocean Power Technologies, Inc. (OPT) in Pennington, NJ (with subsidiaries in the UK and Australia) and Northwest Energy Innovations, LLC (NWEI) in Portland, OR. Let’s take a look at their products

Ocean Power Technologies, Inc. (OPT)

OPT ( is the developer of the PowerBuoy®, which is a moored ocean buoy that extracts energy from the heave (vertical motion) of ocean waves and converts this into electrical energy for marine applications (i.e., offshore oil, gas, scientific and military applications) or for distribution to onshore facilities and/or connection to an onshore electric power grid. OPT currently offers PowerBuoy® in two power output ranges: up to 350 watts and up to 15 kW.

PowerBuoy   Source: OPT

The modest output from individual PowerBuoys® can be combined via an Undersea Substation Pod into a scalable wave farm to deliver significant power output to the intended user.

PowerBuoy wave farmOPT wave farm concept. Source: OPT

You’ll find a description of PowerBuoy® design and operation on the OPT website at the following link:

OPT describes their PowerBuoy® as follows:

“The PowerBuoy consists of a float, spar, and heave plate as shown in the (following) schematic…… The float moves up and down the spar in response to the motion of the waves. The heave plate maintains the spar in a relatively stationary position. The relative motion of the float with respect to the spar drives a mechanical system contained in the spar that converts the linear motion of the float into a rotary one. The rotary motion drives electrical generators that produce electricity for the payload or for export to nearby marine applications using a submarine electrical cable. This high performance wave energy conversion system generates power even in moderate wave environments.

The PowerBuoy’s power conversion and control systems provide continuous power for these applications under the most challenging marine conditions. The spar contains space for additional battery capacity if required to ensure power is provided to a given application even under extended no wave conditions.”

PowerBuoy diagram    Source: OPT

On the OPT website, you’ll find several technical presentations on the PowerBuoy® at the following link:

Northwest Energy Innovations, LLC (NWEI)

NWEI ( is the developer of the Azura™ wave energy device, which is a moored ocean buoy that extracts power from both the heave (vertical motion) and surge (horizontal motion) of waves to maximize energy extraction. Electric power is generated by the relative motion of a rotating / oscillating float and the hull of the Azura™ wave energy device.

Hull-Float-Pod   Source: NWEI

You can see a short video on the operating principle of the Azura™ wave energy device at the following link:

In 2012, the Azura prototype was fabricated and deployed at the Northwest National Marine Renewable Energy Center (NNMREC) ocean test site offshore from Newport, OR.

NNMREC site mapSource: flickr / Oregon State University

On May 30, 2015, under a Department of Energy (DOE) and U.S. Navy sponsored program, NWEI deployed the improved Azura™ prototype at the Navy’s Wave Energy Test Site at the Marine Corps Base, Kaneohe Bay, Oahu, Hawaii. The Azura prototype extends 12 feet above the surface and 50 feet below the surface. It generates up to 18 kW of electricity.

NWETS site photo Source: NWEI

You can view a short video on the Azura being installed at the offshore site in Kaneohe Bay at the following link:

In September 2016, the Azura™ prototype reached a notable milestone when it became the first wave-powered generator connected to a U.S. commercial power grid.


I think we all can all agree that the technology for wave-generated power still is pretty immature. The cost of wave-generated power currently is very high in comparison to most alternatives, including wind and solar power. Nonetheless, there is a lot of energy in ocean waves and the energy density can be higher than wind or solar. As the technology matures, this is an industry worth watching, but you’ll have to be patient.



Just What are Those U.S. Scientists Doing in the Antarctic and the Southern Ocean?

The National Academies Press (NAP) recently published the report, “A Strategic Vision for NSF Investments in Antarctic and Southern Ocean Research”, which you can download for free at the following link if you have established a MyNAP account:

Print Source: NAP

NSF states that research on the Southern Ocean and the Antarctic ice sheets is becoming increasingly urgent not only for understanding the future of the region but also its interconnections with and impacts on many other parts of the globe. The research priorities for the next decade, as recommended by the Committee on the Development of a Strategic Vision for the U.S. Antarctic Program; Polar Research Board; Division on Earth and Life Studies; National Academies of Sciences, Engineering, and Medicine, are summarized below:

  • Core Program: Investigator-driven basic research across a broad range of disciplines
    • NSF gives the following rationale: “…it is impossible to predict where the next major breakthroughs or advances will happen. Thus to ensure that the nation is well positioned to take advantage of such breakthroughs, it is important to be engaged in all core areas of scientific research.”
      • NSF notes, “…discoveries are often made by single or small groups of PIs thinking outside the box, or with a crazy new idea, or even just making the first observations from a new place.”
    • Examples of basic research that have led to important findings include:
      • Ross Sea food chain is affected by a high abundance of predator species (whales, penguins and toothfish) all competing for the same limited resource: krill. Decline or recovery of one predator population can be seen in an inverse effect on the other predator populations.  This food chain response is not seen in other areas of the Antarctic ice shelf where predator populations are lower, allowing a larger krill population that adequately supports all predators.
      • Basic research into “curious” very-low frequency (VLF) radio emissions produced by lightning discharges led to a larger program (with a 21.2-km-long VLF antenna) and ultimately to a better understanding of the behavior of plasma in the magnetosphere.
  • Strategic, Large Research Initiatives –  selection criteria:
    • Primary filter: compelling science – research that has the potential for important, transformative steps forward in understanding and discovery
    • Subsequent filters: potential for societal impact; time-sensitive in nature; readiness / feasibility; and key area for U.S. and NSF leadership.
    • Additional factors: partnership potential; impact on program balance; potential to help bridge existing disciplinary divides
  • Strategic, Large Research Initiative – recommendations::
    • Priority I: The Changing Antarctic Ice Sheets Initiative to determine how fast and by how much will sea level rise?
      • A multidisciplinary initiative to understand why the Antarctic ice sheets is changing now and how they will change in the future.
      • Will use multiple records of past ice sheet change to understand rates and processes.
    • Priority II: How do Antarctic biota evolve and adapt to the changing environment?
      • Decoding the genomic (DNA) and transcriptomic (messenger RNA molecules) bases of biological adaptation and response across Antarctic organisms and ecosystems.
    • Priority III: How did the universe begin and what are the underlying physical laws that govern its evolution and ultimate fate?
      • A next-generation cosmic microwave background (CBM) program that builds on the current successful CMB program using telescopes at the South Pole and the high Atacama Plateau in Chile and possibly will add a new site in the Northern Hemisphere to allow observations of the full sky

You will find detailed descriptions of the Priority I to III strategic programs in the Strategic Vision report.


Sea Change: 2015 – 2025 Decadal Survey of Ocean Sciences

A new book by the above title has been published by The National Academies Press (NAP).

NAP Sea Change  Source: NAP

As described in the NAP abstract for this book:

In the United States, the National Science Foundation (NSF) is the primary funder of the basic research which underlies advances in our understanding of the ocean. Sea Change addresses the strategic investments necessary at NSF to ensure a robust ocean scientific enterprise over the next decade. This survey provides guidance from the ocean sciences community on research and facilities priorities for the coming decade and makes recommendations for funding priorities.

If you have set up a MyNAP account as described in my 14 March 2015 post, then you can download a pdf copy of this book for free at the following link: