Features Sustainability
Power Struggle: Is RAS still on the right path to energy efficiency?

Over the years the questions remain the same: are RAS efficient and sustainable? Is technology fulfilling the requirements? Should we investigate bigger production systems? Do we really know what we are looking for or understand what fish farming really means? 

Two of my peer-reviewed articles – one of them being one of the most downloaded papers of a journal for several years – are based on surveys. I am convinced that this is an important way of knowing the reality of a situation. Questions are made for hands-on people, people who see daily what the issues and the real performance of RAS are. That is why, to answer those questions, I asked different juvenile and grow-out operators in the Atlantic, coho and Steelhead spectrum to help me. (Thank y’all for your insights and time!)

The question that has always been in my mind is if land-based farming is more energy efficient than growing part of the cycle in land and part in cages. Energy usage, not only from an economic perspective but also from an environmental view, is what really concerns me. 

Saying that being “local” and “close to the market” are what people focus on. Fish transportation is one of the main issues energy-wise. 

As pointed out by André Bravo (COO at Local Coho), the term “local” by USDA definition means production within 400 miles from land to market. As Steve Summerfelt, CSO at Superior Fresh, commented, producing fish next to the market could save lots of energy during transportation when compared to air freight from different continents. And this could make the difference, not considering the significant shipping cost savings. 

John Holder, president at JLH Consulting Inc. and personally one of my designing mentors, pointed out that although this will depend on the system, a RAS (as moving and treating the process water) would not be considered efficient if the power consumption is over five kWh/kg fish produced.

Sea cages are becoming more and more expensive to manage with sea lice and the loss of their social licenses in several regions is just one of the examples. Moreover, RAS hard structures will last over 25 years and more consumable equipment lifetime will be greater than 10 years, most just needing maintenance not replacement. 

Thus, talking about maintenance and the main factors driving the energy consumption in RAS – pumping the water to degassing (i.e. elevated stripping towers), using non-efficient equipment (i.e. equipment selection), mega tanks, small pipes, poor design in water flows, management competence and system design – were mentioned. 

Alejandro Rojas, COO at AquaBounty, said something that really caught my attention. He said, “You define your future the day you design and sign for your system.” And such design should be directed towards an adequate footprint, avoid unnecessary expenses, completely energy-efficient building with minimal energy gain or losses. If he had all the money in the world, he would design to preclude the need to heat or cool down the water. If we focus on OpEx we would be using more resources daily and operations. 

As such, investors should look more into the CapEx. Investing more at the beginning would save resources and money. We cannot investigate the smaller picture. Short-term objectives will give immediate profitability, but this is not compatible with the “green” world. 

When designing, energy is to be considered or has been considered. For example, sizing pipes to have the least amount of friction but keep clean, and searching for the use of renewable energies that are available on site. You can always invest in clean energy, but you also have to buy what is available wherever you are planning to build your system. 

Nevertheless, what is true and now I have proof of something that I have been believing since I started my career, North America and Norway are fortunate to have relatively inexpensive power compared to the EU and southern Norway making energy non-important for the rest RAS aquaculture producers in the world. 

RAS can be an efficient technology, especially when systems are designed to produce high biomass levels of fish per unit kW. However, current mega constructions and companies claiming massive productions are having same issues: the expected energy requirement to produce fish reaching the market is not real and the capital investment must survive on less than half of the revenue which is most of the times insufficient to save the investment. 

Thus, if the business fails, what happens with all the energy that went into the construction? It is lost unless the farm can be repurposed, something most of the times impossible due to the mentioned mega tanks and colossal constructions. Again, is bigger the better? Or should we look for smaller but smarter ones?

Overall, I have to say that I am happy to see that all my contributions have responded positively to the question if energy is being monitored in their systems or systems they have built. Via SCADA, BluEdge by Sensaway, with power-logic digital meters at every service entry and whenever the information is available being lowers, drum filters and pumps the main assessed equipment. 

Even more some energy audits are being performed to see where the energy peaks happen and thus addressed. Moreover, the use of LED lights is being extended (both because they are energy efficient, and because they release less heat than other types of lighting) as well as high-efficiency pumps and motors with variable frequency drivers. 

There are always two sides of the coin as we say in Spanish. There are always different perspectives to look at things. There is always room to adjust your ideas as you learn. I have been in this industry for the last 13 years, always very focused on how to justify and improve the use of energy in RAS. 

I have learned that aquaculture is needed as well as other animal production industries. So, the use of energy will be required no matter what as the world population increases and protein needs to be produced. The energy that pumps, filters and even, lights for an efficient RAS are simply the life support and wastewater treatment burden that we are carrying to protect the environment. 

Should U.S. cities, like Tampa or Orlando, turn off their wastewater treatment plants to reduce their energy/carbon footprint? Of course not. During my conversation with Steven Summerfelt he stated that a RAS farm is simply paying to treat the wastewater so that the environment does not have to carry the wastewater/pollution burden while net pen producers do not capture any of the fish wastes, forcing the environment to mitigate these nutrients.  

Maddi Badiola, PhD, PM, is a RAS engineer and co-founder of HTH Full Spectrum based in Basque Country, Spain and USA. She is executive director of the Florida Marine Aquaculture Coalition. Her expertise include energy conservation, lifecycle assessments and RAS global sustainability assessments. Email her at mbadiolamillate@gmail.com.