23rd October

Marine biomass to supplement world energy requirements?

Declan Hanniffy, Research Coordinator, OceanFuel Ltd

Today around 90% of the world’s energy consumption derives from the combustion of fossil fuels, i.e. coal, oil and natural gas are in limited supply and will one day run out. As a result, the quest for renewable energies – energies generated from natural resources such as sunlight, wind, tides, etc and from industrial or urban waste and biomass – started decades ago. Induced by numerous studies and energy conferences, the 27 Member States of the EU decided in 2007 that 20% of energy should come from renewable sources by 2020 (Lisbon Treaty).

Cultivating seaweed

Cultivating seaweed

There is a need to fulfil our energy consumption in a renewable and sustainable way, and aquatic biomass could be one source of this energy. Since the available area for cultivation at sea is so much larger than on land (70% of the earth’s surface is ocean) and growth rates of macroalgae (also commonly known as seaweed) are much higher than for conventional land crops, the potential for biomass production at sea is enormous.

Aquaculture for energy production can also avoid discussions and debate around food crops for fuel (the food-energy nexus); sustainability; fresh-water usage pesticides and land use change.

Also, fertilisation (adding nutrients to improve crop growth), which has a major effect on greenhouse gas balances of crops on land, can be altered or even be diminished when cultivating in an aquatic environment.

The reduction of greenhouse gases achieved by using aquatic biomass for energy and fuel purposes is therefore, in most cases, greater than for the more conventional biofuels produced from crops (e.g. sugarcane, corn) on land.

Open sea cultivation
Today, aquatic biomass cultivation in Europe is a logistically complex multistep process with onshore hatcheries and early grow-out stages and offshore farms where the plants grow to maturity and are harvested. It is mainly based on small volume production using long ropes and manual harvesting. As a result, production costs per biomass unit are much too high.

AT~SEA (Advanced Textiles for Open Sea Biomass Cultivation) is a three-year European funded project involving a consortium of 11 partners (six SMEs and four RTDs – Research and Technical development). It is coordinated by a large enterprise, Sioen Industries. The partners are from Norway in the north down to Morocco in the south, along with Spain, Portugal, Scotland, Netherlands, Belgium and Ireland.

The aim of AT~SEA is to develop and apply advanced textiles to facilitate open sea cultivation of seaweed species which have high-potential as a source for renewable energy and fuels. The idea is to cultivate seaweed onto advanced textile substrates that are installed below the water surface (typically 1-5 m depth) as a kind of secondary sea bottom.

The surrounding infrastructure (mooring system, floatation tubes, storage, cleaning, and regeneration and transportation tanks) will also be based on advanced textiles.

OceanFuel Limited will work closely with the project partners to advise on seaweed cultivation and system requirements which will all feed into a final system design. OceanFuel will also take the lead in demonstrating the usage of onshore facilities at the Inagh Valley Trust facility in Connemara, and offshore facilities in a 10ha site in Cleggan Bay as a testing ground for the system. Trials will also be carried out on products designed by the project partners before the best products are combined in a final proof of concept design.

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