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Creating Systems to Capture & Utilize CO2 Effectively is ImportantIzuru Senaha

<Series 1 / complete>


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Projects to cut CO2 to address global warming is a serious topic that concerns the whole world. Emission levels are seen as the primary problem, but research is underway in Okinawa to implement a Carbon Recycling System to utilize CO2 effectively as a resource.
This expert interview introduces the key figure behind a carbon recycling system known as the “Project for Seaweed (Sea Grapes) Cultivation Using CO2 Dissolution Equipment.” Professor Izuru Senaha is involved in the Energy Systems Engineering course at the University of the Ryukyus, Faculty of Engineering.
Born and raised in Okinawa, he stayed there to continue his studies and research. This 4-part interview focuses on his research about systems for CO2 reduction and reuse of greenhouse gas using marine biomass.

Part 1 discusses the effective utilization of CO2 as a renewable energy resource. He also reveals the circumstances that led to the project for seaweed cultivation using CO2 dissolution equipment.

CO2: Ranking & Effective Utilization

Currently, the whole word recognizes CO2 as a “greenhouse gas” that contributes to global warming. There are also many economic systems built around this concept. Personally, I still feel some skepticism about exactly how much impact CO2 is having on global warming. However, it’s unlikely that society will ever return to thinking that CO2 emissions don’t matter. The fact is that “CO2 reduction” has become a huge social issue over the past 10 years.
So here we are, and it’s more important than ever to create systems to decide how to stop CO2 emissions and how to effectively utilize captured CO2 emissions.

The most efficient way to reduce CO2 is to capture CO2 from gas emissions of large thermal power plants. Actually, around half of CO2 emissions in Japan is from gas emissions of thermal power plants.
For example, if you want to reduce domestic CO2 by 5-10%, it would be impossible to capture CO2 from plumes of car exhaust. But thermal power plants are putting out a lot of gas every day, so it would be most effective to capture and process those emissions immediately to reduce CO2.
If we could capture all the CO2 emissions just from Okinawa’s power plants, then we would reduce the CO2 in Okinawa by 50%.The CO2 in this exhaust is around 400 times more concentrated than regular air. If you think of it another way, it would take 400 times as much effort to capture the same amount of CO2 from regular air.
When it comes to resources and energy, I think that their value increases with quantity and concentration. CO2 itself isn’t evil, it isn’t anything at all. But if we can concentrate it into a pure object, it will gain value as a resource. CO2 is used in manufacturing, and industries that want to use CO2 love it because it’s a cheap and renewable resource.

Every form of media is giving large scale coverage to CO2 reduction and its relationship to global warming. Perhaps people still aren’t understanding that half of our emissions are coming from thermal power plants. It seems obvious that the most effective way to capture CO2 would be to get most of it directly from the source of emissions.
Next, we’ll learn about the circumstances that led from “carbon recycling systems” for captured CO2 to the Project for seaweed cultivation using CO2 dissolution equipment. The first step is to discuss the state of manufacturing in Okinawa.

Okinawan Industry for a Sustainable Society

Even before Senaha started working on the seaweed cultivation project, he had dreams of developing new industries in Okinawa. Every year, The University of the Ryukyus hosts 400 students at the Faculty of Engineering. Together with technical high schools, over 2000 engineering students graduate in Okinawa each year. However, work in Okinawa prefecture is mostly tertiary sector (service industries), with secondary sector (manufacturing industries) severely lacking. As a chain of smaller islands, the resources required for manufacturing must be imported, and finished products require transportation beyond the islands. These circumstances mean significantly higher costs, so Okinawa is not an ideal location for manufacturing.

Okinawa industry sectors: Compared to to other prefectures, the second sector is small and the tertiary sector is very large
(Source: Okinawa Prefectural Government homepage)

Although more than half the students who graduate from engineering departments and technical high schools want to stay in Okinawa, it is very hard to find engineering jobs. Likewise, even if they apply to companies within Okinawa, most companies are unable to expand their employee pool. These circumstances led Senaha to believe that secondary sector industries using new engineering tech must be created. But the truth remains that islands are not ideal for manufacturing. He was feeling completely stuck when he realized that it was necessary to create secondary sector industries that were specifically suited for Okinawa’s island environment.
The most obvious features of Okinawa prefecture’s natural resources are a subtropical climate and the wide ocean surrounding it. Local residents desire a sustainable society, and demand that any new industries avoid damaging Okinawa’s natural environment.
Over the past 10 years, Senaha has been discussing this issue with colleagues and researchers in other fields, searching for advice. He came to a conclusion after considering many different things he heard from their ideas: carbon recycling systems. The effective utilization of CO2 as a resource is the ideal solution for Okinawa, and for building a sustainable society. Part 2 discusses the details of this concept, and introduces the Project for seaweed cultivation using CO2 dissolution equipment.

Interview Date: December 18, 2018



Creating Systems to Capture & Utilize CO2 Effectively is Important

Innovation in Seaweed Cultivation to Build a Recycling Society

Introducing IoT & AI to Provide Ideal Conditions for Seaweed Cultivation

Keep Trying New Things to Discover the “Right” Project

Izuru Senaha

Born 1967 in Okinawa. Graduated 1991 from the University of the Ryukyus, Faculty of Engineering, Energy and Mechanical Engineering Department. Continued at the University of the Ryukyus as an assistant after completing his MS Mechanical Engineering in 1993. Awarded PhD Engineering from Nagoya University Graduate School of Engineering in 2001. Returned to the University of the Ryukyus as an associate professor of Engineering in 2006, and accepted a position as full-time professor in 2018. Began research on CO2 reduction and utilization using marine biomass in 2009. His current research project is investigating the early development of seaweeds like sea grapes (umibudo) and Nemacystus decipiens (mozuku) through cooperation with a diverse spectrum of other research institutes to contribute to fields of industry in Okinawa.

Awards & Honors (Selected)
・2009 Contribution to Society Award
・2010 Faculty of Engineering Contributor Award
・2010 IMPRES 2010 Best Poster Award
・2013 Rocky Challenge Award

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