OTEC – what is and why should we consider it?

Mr. Wayne Raymi Kijiner is the President of the Marshall Islands Student Association, University of the South Pacific, and Undergraduate: BSc Double Major Electrical/Electronic Engineering & Physics 

There is a new but old technology making its way around the green energy discussions. I'm referring to Ocean Thermal Energy Conversion (OTEC). The technology has been understood since the 1800s, but it wasn't until the last 15 years that significant advancements were made and are currently being developed for improved designs.


 What exactly is OTEC, and how does it work? In a nutshell, it is the use of the temperature difference between the surface and the deeper parts of the ocean to heat and cool a working fluid (usually ammonia).  Because the working fluid has a low boiling point, there is no need for a significant temperature difference; it should be at least 20°C. The working fluid is then heated using surface ocean water, causing it to turn into vapor pressure, which is used to drive the generator turbines, allowing electricity to flow. The vapor is then condensed back into liquid form by cooling with deep ocean water. As a result, the cycle continues to produce a steady output of electrical energy. Aside from electricity, OTEC stations can generate two other byproducts: hydrogen and water. Hydrogen (H2) will be the clean fuel of the future, and water (H20) is the main source of life. So, with a single OTEC station, you have four products: electricity, hydrogen, fresh water and a continuous supply of clean, nutrient rich and very cold seawater. The latter can be used for Sea Water Air Conditioning (SWAC) and aquaculture. The vapor is then condensed back into liquid form by cooling with deep ocean water. As a result, the cycle continues to produce a steady output of electrical energy. Aside from electricity, OTEC stations can generate two other byproducts: hydrogen and water. Hydrogen (H2) will be the clean fuel of the future, and water (H20) is the main source of life. So, with a single OTEC station, you have four products: electricity, hydrogen, fresh water and a continuous supply of clean, nutrient rich and very cold seawater. The latter can be used for Sea Water Air Conditioning (SWAC) and aquaculture.

 

You're probably thinking by now, "this is too good to be true or OK, but what's the catch?" Well, it only works if you're geographically close to the equator, have easy access to very deep seawater and it doesn't work in colder locations. That's hardly a disadvantage for us; in fact, it's an advantage. This is why, together with solar, hydro, and wind, it is likely one of the best renewable technologies for the Pacific region. If anything, it is well worth contemplating a hybrid electrical system that combines all four, supplying enough to provide the majority of our electrical demand, particularly in low-lying islands and rural areas. And if we can produce surplus renewable electricity, then we are on the track to being able to make our own hydrogen.

 

This isn't to argue that OTEC is a perfect technology. It has limitations, just like any other. But all research shows the potential, especially for the atoll nations such as my own. We still have work to do to bring this technology to maturity. Most previous attempts at OTEC in the past have failed primarily on the economic side, and everyone has been afraid to even consider it.  Our partners at KRISO in Korea led this work internationally and are preparing a 1-MW trial plant in Kiribati as I write.  At MCST we are now preparing for the Marshall Islands first demonstration plant.  A few of us are hard at work to understand the real potential, costs and benefits of this technology, and I expect the rest of us in the Pacific region will consider following suit. It is time to take action and practice what we preach and move towards a renewable and sustainable future.


Comments

Post a Comment

Popular posts from this blog

Go Sail Cargo – The new Corporate Entity and its potential

Image
In order to steer Go Sail Cargo towards sustainable zero-carbon growth and global expansion, a new business entity must be created. Capital raising is first on the list and here we must be clear in our goals and informed as to how to achieve them, but thinking laterally and being prepared to abandon preconceived ideas, unless they dovetail with the aims of the new company, is essential. In order to be taken seriously any new entity must present a practical, viable, scalable and profitable proposition that is demonstrably beneficial to all stakeholders. One that fulfills a clearly identified need and does so in a non-invasive and non-polluting manner for the foreseeable future. Go Sail Cargo ticks all those boxes. It is my aim to develop a structure that is essentially cooperative in ownership and concordant in action. Specifically, the Pacific Nations, with their overwhelming dependence on maritime transport and centuries of advanced and intuitive navigational skills s
Read more

Shipping solutions – a call to arms

Image
For every time, every decade there are solutions. Mine are based on common sense and the need to take action. We offer true Zero-emission ships like our versatile C-100, not half-hearted compromises. Vessels that can be efficiently mass produced combining the best of time-tested sailing ships with the very best of proven technology. We’re ready to go, here’s how.   Zero-carbon operation is available right now by optimising the ships and reducing the power use.   The fully optimised ship , working with maximum efficiency starts with a computer-tuned hull for maximum performance, a safe, stable carrier that can be relied on to deliver the goods. Racing technology is applied to proven, practical rigs, the sail power is multiplied. Using wind and sun alone, the sails, wind generators and solar all work in unison to drive the vessel.   Reduce the power usage on board. Every single component must function reliably and efficiently by harnessing all available power. Here’s a few examples. M
Read more

Harnessing Nature's Power: Ocean Thermal Energy Conversion and Deep-Sea Water By-products

Image
Introduction In a world where renewable energy sources are becoming increasingly important, Ocean Thermal Energy Conversion (OTEC) stands out as a promising and largely untapped resource. This innovative technology leverages the temperature difference between warm surface water and cold deep-sea water to generate electricity. Additionally, OTEC offers a unique advantage - the utilization of deep-sea water by-products. In this blog, we will delve into the process of Ocean Thermal Energy Conversion and explore the various potential applications of deep-sea water. In my previous blog post I explained a bit about the science behind the OTEC process, if you have not read it you can find it here . However, generally the process can be broken down into four main components. Seawater Selection: The first step in OTEC involves carefully selecting suitable locations where there is a significant temperature gradient between surface water and deep-sea water. These areas are typically found i
Read more