Institute to enhance green efforts with low-carbon strategy - Taipei Times

The Fisheries Research Institute said it has enhanced its green efforts by developing a low-carbon aquaculture strategy that can cut more than 90 percent of power consumption in farming red sea plume.

Red sea plume, or Asparagopsis taxiformis, is rich in bromoform, a substance that can precisely block the methane-producing pathway in the rumen of ruminants.

The institute last year developed an aquaculture technique to mass produce red sea plume for use in cattle feed, with the goal of reducing methane emissions from such ruminant animals.

Photo courtesy of the Fisheries Research Institute's Donggang Aquaculture Research Center

An in vitro rumen fermentation experiment showed that adding only 5 percent red sea plume powder to the feed inhibited emissions from cattle by up to 99.78 percent, the institute said.

In another experiment on cows, adding 0.15 percent red sea plume powder to the feed also significantly inhibited methane emissions from cows by up to 66 percent, it said.

This showed that mass production of the seaweed has strong potential for commercial development as a carbon reduction product, the institute said.

However, the tetrasporophytes of red sea plume are filamentous and would often form clumps, making them easily settle and accumulate in regular land-based aquaculture tanks, it said.

Highly energy-consuming aeration equipment used to be applied to keeping red sea plume suspended in the water, leading to diminished environmental value of the seaweed due to high electricity consumption, the institute said.

To overcome such a barrier, the institute's research team optimized the hydrodynamics of the racetrack tanks, it said.

The conventional blower aeration design was replaced with a variable-frequency paddle wheel aerator, the institute said.

The paddle wheel aerator provides more effective water circulation and less power consumption, using only one-sixth of the electricity required by a blower aerator, it said.

The research team also developed an intermittent operation method to maintain uniform suspension of red sea plume in the water, the institute said.

Strong, intermittent water flow can also prevent diatoms from adhering to tank wall, largely reducing the cost of manual cleaning, it said.

A direct current power supply module was integrated with a 5-kilowatt solar power system to supply direct current electricity directly to the variable-frequency paddle wheel aerator, the institute said.

That can boost solar utilization rate by 4.17 percent by reducing energy conversion loss, it said, adding that up to half of actual power consumption can be cut during intermittent operations.

When sunlight is sufficient, such a power generation module can sustain the concurrent operation of 50 racetrack tanks during the day, it added.

Such a low-carbon seaweed farming strategy can reduce upstream energy consumption, and is expected to help accelerate green transition across the domestic livestock sector in line with the net zero goal, the institute said.