Seaweed energy

A new inexhaustible source of energy

So, you want to grow a crop under water, harvest it by ship, transport it to land to make it ferment and create energy from the gasses that are emitted from the fermentation? That sounds utterly ridiculous. Doesn’t it? 

Believers in the ‘green gold’ will disagree. They think seaweed might be the single most important energy solution for a sustainable future. As far-fetched as it may seem, seaweed counters an important concern about other forms of biomass. Currently, land crops like corn and trees are used as sources of biofuels. They are burned, gassed or fermented and the resulting energy is sold as ‘green’, CO2-neutral energy. Some argue, perhaps rightfully, that it is foolish or even unethical to use soil for growing crops only to burn them. This way, biofuels compete with food crops for land. As food remains scarce in several regions of the world, it is at least arguable to use soil for growing biomass.

Seaweed obviously does not have to compete with food crops for scarce land. Instead, using new technologies, seaweed farms can simply be installed in sea areas up to several kilometers off the coast. A multitude of companies has started experimenting with large textile mats. These mats are strung several meters under sea level – the natural habitat of seaweed – and filled with seaweed crops. Once fully grown, the seaweed is harvested and transported by ship to fermentation plants. The fermentation process emits gasses loaded with methane, the stuff that keeps our furnaces burning and our cars moving.

Indeed, it might seem cumbersome to harvest those weeds all the way off the coast. But over there the seaweed farms only have to compete with marine transport and windmills for available ‘land’ (although some designs even incorporate seaweed farms into windmill parks, using the mills as anchor points for the farm mats).

Over the last years, seaweed’s potential has been attested by scientific evidence. Advice agency DNV GL calculated that by 2035, one quarter of the entire biofuel yield might be from seaweed. One year earlier, the Energy Research Centre of the Netherlands said that if one tenth of the Dutch North Sea would be used for seaweed harvesting, this could yield 350 petajoules of electrical energy per year. This is more than the entire current yield of all Dutch windmill parks together.

Currently, the first industrial-scale seaweed farms are being tested. Producers have to prove that the farms do not negatively affect the ecological health of marine life in the vicinity of the farms. Critics have pointed to the fact that seaweed consumes nutrients in the seawater, and that it is not yet known how this influences other sea-organisms. 

If the tests prove seaweed farms to be harmless for marine life, nothing stands in the way of green gold fever igniting. And perhaps you too will turn the heater on and relax in the warmth provided to you by green, slimy plants from the ocean.

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