Gas is the future. That may sound counterintuitive in an emerging world of renewable energy where new solar power records are set on a monthly basis. However, for Joost Wouters, Dutch engineer and entrepreneur at The Seaweed Company and Inrada Group, there’s no doubt: in the future, we will continue to use gas-fired stoves to cook our meals and warm our homes with gas-burning heating systems. Gas? Yes, biogas from seaweed.
It’s a sad fact that—at a moment when renewable clean energy is rising fast—a final surge of fossil fuel exploration mostly through fracking is causing immense environmental degradation and pollution around the planet. The International Energy Agency (IEA) recently projected that oil production through fracking will cover 80 percent of new global demand for oil in the next three years. Most of that new oil production will come from the U.S. where fracking has increased from 23,000 wells producing some 100,000 barrels per day in 2000 to more than 300,000 wells producing over 4 million barrels per day in 2015. Today, more than 50 percent of the U.S. oil production comes from fracking.
In the past years, the Inrada Group ran several experiments in different parts of the world and created a very compelling business case to replace fracking in the short term and all oil and gas exploration with biogas from seaweed. Joost Wouters: “Seaweed is produced by nature. You don’t have to pay for the CO2. You don’t have to pay for the sunshine nor for the salt water.” He runs the numbers based on recent tests off the coast of Cape Town in South Africa: one hectare of seaweeds produces—in multiple annual production cycles—as much as 800 tons biomass per year. That biomass can be converted into 160,000 cubic meters of biogas per year or 120,000 cubic meters of methane per year. A successful shale gas field in the U.S. has an output of some 50 million cubic meters per year. Wouters: “That means that approximately 450 hectares of seaweed plantations replace the production of a shale gas field.”
Cost comparison calculations by Inrada—confirmed by Shell and Accenture—show that seaweed biogas outperforms shale gas by up to a factor 4. Shale gas can only be competitive at around 50 dollars per barrel. Seaweed gas can be produced for 12 to 15 dollars a barrel. Wouters explains the productivity of seaweed referring to the three-dimensional environment of the plantations. The seaweed grows at depths of up to three-meters, unaffected by gravity. That allows for a volume and a speed of conversion of solar energy that are impossible to achieve in farming in a two-dimensional environment on land. In addition, water is 784 times denser than air and supplies a multiple of nutrients.
Inrada has developed modular semi-submersed structures to grow seaweed. Seaweed spores are collected on ropes. The ropes are attached to the structures. At the time of harvest, the ropes are pulled through a harvesting machine that cuts off the seaweed. The biomass is subsequently fed into a digester. The seaweed digester is a key innovation by Inrada. Because of its biological composition, traditional biomass digesters don’t work well with seaweed, according to Wouters.
Fracking comes at a high price. In 2010, the U.S. Environmental Protection Agency (EPA) estimated that between 250 to 500 billion liters of water were used to fracture 35,000 wells. Today, that precious, fresh water use would be 10-fold—in the U.S. only. Oil companies add chemicals to the water to facilitate the fracking process. They say that the concentration of chemicals in the frack fluid is low: only two percent. However, two percent of 2,5 trillion liters is still 50 billion liters of poisonous chemicals seeping into groundwater supplies and endangering public health.
Whereas we have become used to the fact that most industrial processes have “hidden costs” for the environment and public health, Wouters points out that seaweed production comes with “hidden benefits”. “Fracking spills water and destroys the environment. By contrast, seaweed produces drinking water and regenerates the environment, says Wouters”. Inrada began the tests in South Africa in “dead sea water where you couldn’t see anything alive after an intensive fish farm had exhausted the marine environment”. As the seaweed began growing, fish and shells started to come back. Wouters: “Pollution is creating acidity in the oceans and that threatens marine life. Seaweed alkalinizes the water again.” In addition: each hectare of seaweed delivers 680,000 liters of fresh—not salt—water while the growth process sequesters CO2.
There’s more. After digestion, the seaweed residue is an ideal fertilizer. In fact, countries used to farm seaweed as a fertilizer prior to the invention of chemical fertilizers about a century ago. Today, many countries import natural gas to produce fertilizer. The seaweed biomass also provides a great source for animal feed: seaweed can replace the soy plantations that have depleted vast areas of agricultural soils for our growing meat consumption.
Wouters’ list of seaweed benefits keeps growing: nearly all processed and frozen foods around the world include seaweed extracts to maintain softness and texture. Seaweed extracts such as agar-agar and carrageenan are key ingredients of products like toothpaste, ice cream, and cosmetic creams and lotions. Seaweed can also provide fibers for the textile industry. In the 1940s British scientists already discovered that fibers from seaweeds could be used as non-toxic, non-irritating, biodegradable woven material to treat wounds. Seaweed-based gauze has an anti-inflammatory capacity as well while it maintains a certain degree of humidity which supports wound healing.
There’s one ultimate factor that makes the seaweed biogas case extremely compelling: the infrastructure already exists. The clean energy provided by wind and solar requires big infrastructural investments. Seaweed biogas, however, can be fed into existing pipeline networks that run across the globe connecting factories and homes to a secure energy supply. That’s why Wouters says: “gas is the future”. Granted, we need to build the floating platforms to grow the seaweed, but—at a price of $25,000 per hectare—that is hardly a prohibitive investment compared to the millions of dollars needed to explore a fracking well. The digester requires an additional investment. Wouters envisages using depleted oil or gas rigs to host digesters offshore and prevent the shipment of heavy biomass. The rigs already have pipelines that bring their production to land.
The seaweed revolution is “brewing”. Wouters: “I hear myself talking, it is almost too good to be true. But it’s reality that as long as the sun shines and there is water in the oceans, seaweed provides an unending supply of clean, renewable energy with many additional benefits.”
By JURRIAAN KAMP