Brown Seaweed to Biofuels and Chemicals......Breakthrough?

The key benefits of BAL technology are:
Single Platform. BAL converts seaweed carbohydrates into one renewable chemical intermediate that is affordable and scalable for both fuels and chemicals.


Commercial Focus. Leveraging the single platform, BAL will first commercialize high-value products to generate early cash flow that simultaneously paves the path for larger market opportunities.


First Mover Advantage. With over 60 patents or patents pending, BAL has carved a broad IP estate for the use of seaweed as a biomass for chemicals and fuels.

Products
BAL has developed a diverse product portfolio that provides large market opportunities at varying price points. Products include road transport fuels, green plastics, surfactants, agrochemicals, synthetic fibers and nutraceuticals. _BioArchitectureLab

BALWhat did the researchers at Bio Architecture Lab actually achieve?

Prospecting macroalgae (seaweeds) as feedstocks for bioconversion into biofuels and commodity chemical compounds is limited primarily by the availability of tractable microorganisms that can metabolize alginate polysaccharides. Here, we present the discovery of a 36–kilo–base pair DNA fragment from Vibrio splendidus encoding enzymes for alginate transport and metabolism. The genomic integration of this ensemble, together with an engineered system for extracellular alginate depolymerization, generated a microbial platform that can simultaneously degrade, uptake, and metabolize alginate. When further engineered for ethanol synthesis, this platform enables bioethanol production directly from macroalgae via a consolidated process, achieving a titer of 4.7% volume/volume and a yield of 0.281 weight ethanol/weight dry macroalgae (equivalent to ~80% of the maximum theoretical yield from the sugar composition in macroalgae). _Science Abstract

They increased the fermentation yield of ethanol from brown algae by genetic tweaking of their microbial fermentation platform.

Seaweed can be an ideal global feedstock for the commercial production of biofuels and renewable chemicals because in addition to its high sugar content it has no lignin, and it does not require arable land or freshwater to grow. Globally, if three percent of the coastal waters were used to produce seaweed than more than 60 billion gallons of fossil fuel could be produced. Today, in many parts of the world, seaweed is already grown at commercial scale. BAL currently operates four seaweed farms in Chile and has had great success in growing seaweed at economically viable production yields.

...“BAL's technology to ferment a seaweed feedstock to renewable fuels and chemicals has created an entirely new pathway for biofuels development, one that is no longer constrained to terrestrial sources,” says ARPA-E Program Director Dr. Jonathan Burbaum. “When fully developed and deployed, large scale seaweed cultivation combined with BAL’s technology promises to produce
renewable fuels and chemicals without forcing a tradeoff with conventional food crops such as corn or sugarcane.” _BAL (PDF)

It is far easier to grow large quantities of macro-algae in the sea, than microalgae. Macro-algae is much tougher and holds together in large masses for easier harvesting. Up to 4 crops a year can be grown, at very rapid biomass rates.

It should be clear that by adding roughly 70% of the earth's surface area to one's potential crop growing area, the limits to biomass growth have been expanded considerably.

H/T NextBigFuture

More from Green Car Congress

Fuels from the Sea: Micro-Algae and Macro-Algae

Marine ecosystems are an untapped resource that account for over 50% of global biomass and seaweeds themselves are capable of producing more biomass per square metre than fast growing terrestrial plants such as sugar cane. _Daisy Brickhill

On the micro-algae front, scientists from the U. of Western Ontario have discovered a way to increase the growth of algae by almost a factor of 4. They did this using magnetic fields!

Wankei Wan, a professor of biochemical engineering at the University of Western Ontario, thinks he's found a potentially significant way to stimulate algae growth.

Wan and a team of research students built a small raceway pond - a tabletop pond shaped like a racetrack, that is - and began growing a common type of single-celled algae called Chlorella kessleri.

They measured the pace of algae growth and oil production. They then changed the set-up such that the algae in the pond were circulated through an area exposed to static magnetic fields.

What they observed, which is described in an upcoming research paper, surprised them.

The magnetic field exposure “almost quadrupled the biomass and lipid (oil) production rate in raceway ponds,” according to the paper.

Wan's team also noticed the magnetically stimulated algae produced dramatically more antioxidants, such as Astaxanthin - often used as a food supplement.

In an interview, Wan said the algae behaved differently depending on the strength of the magnetic fields and length of exposure to them. The researchers noticed that growth would increased steadily as field strength grew. Then, once peak growth was reached, there would be a steep decline.

This suggested to Wan that there is a “sweet spot,” that might vary depending on the type of algae being grown. _CheckBiotech

On the macro-algae front, scientists at Aberystwyth University have found that kelp contains higher levels of carbohydrate at the peak of summer. They suggest that this may be the best time to harvest kelp for biofuels production.

Collecting monthly samples of kelp from the Welsh coast researchers used chemical analysis to assess the seasonal variability. Their results, which will be presented at the Society for Experimental Biology Annual Conference in Glasgow on the 4th of July, showed that the best month for biofuel harvest was in July when the kelp contained the highest proportions of carbohydrate and the lowest metal content.

Kelp can be converted to biofuels in different ways including fermentation or anaerobic digestion producing ethanol and methane or pyrolysis, (a method of heating the fuel without oxygen) which produces bio-oil. The chemical composition of the seaweed is important to both of these processes.

Research into biofuels has focused on terrestrial plants; however these have the serious drawback of the conflict between using land to grow food or fuel. Marine ecosystems are an untapped resource that account for over 50% of global biomass and seaweeds themselves are capable of producing more biomass per square metre than fast growing terrestrial plants such as sugar cane. _DaisyBrickhill

The assumption of the researchers is that the kelp will be used in the fermentation of ethanol or anaerobic fermentation of methane -- which may not be a wise assumption in the long run. Gasification or pyrolysis of macro-algae depend far less upon the chemical constituents and far more upon absolute biomass. It is those thermochemical approaches which are better positioned to take advantage of the prolific nature of marine aquaculture. Macro-algae can produce up to 6 harvests per year, depending upon local conditions.

Terrabon Announces 70 gal / ton bio-gasoline from Waste

Through an advanced bio-refining technology, MixAlco® converts materials such as municipal solid waste (MSW), sewage sludge, forest product residues such as wood chips, wood molasses and other wood waste, and non-edible energy crops such as sweet sorghum into a wide array of chemicals and secondary alcohols that can be further refined through separate, well-established processes to produce renewable gasoline, jet fuel or diesel. The gasoline produced through the MixAlco® technology is not ethanol. In fact, it has a higher energy value than ethanol and can be blended directly with gasoline produced from hydrocarbons. _Terrabon

TerrabonHouston based Terrabon creates advanced gasoline-like biofuel from mixed waste biomass, including sewage and solid waste. The company utilises a non-sterile anaerobic digestion for this versatile feedstock mix.

Terrabon’s MixAlco process is described by Luce as a linkage of biological fermentation and chemical processes. It begins by treating the feedstock with lime to enhance its digestibility, and then fermenting the biomass using a mixed-culture of microorganisms to produce a mixture of carboxylic acids. Calcium carbonate is added to the fermentation to neutralize the acids to form corresponding carboxylate salts, which are then dewatered, concentrated, dried and thermally converted to ketones. The ketones are then hydrogenated to alcohols that can be refined into renewable gasoline, diesel or jet fuel blendstocks.

“When we have those ketones, we use parts of the zeolite and hydrogenation catalysts,” Luce said. “Once we get through the organic acids, we actually create a whole series of secondary alcohols and then we use the same zeolite catalyst structure. The research with CRI that we’ve done is making sure the catalyst structure is set up in a way to optimize through the mix of ketones that we create.”

Terrabon’s cellulosic gasoline product, according to Luce, is a viable drop-in renewable gasoline blendstock that looks similar to cracked gasoline that comes off the fluid catalytic cracking conversion process, a pathway commonly used by today’s petroleum refiners.

“It ends up being a subcomponent of RBOB, which then ethanol can be put on top of to fulfill the RFS2 mandate,” Luce said. “What we’re hoping is that as we begin scaling it up that we can take on the next generation of catalysts to actually make it into a finished product, blend it with ethanol and make E85 straight to the retail station. But, that’s probably version three or four in our vision of what we’re trying to do. First, we want to show we can economically make a drop-in biofuel and use existing infrastructure and satisfy some of this RFS2 mandate.”

Terrabon’s work isn’t satisfied at stopping at this milestone. The company is in the process of engineering scale-up strategies in hopes of bringing its first commercial production plant online. “We’re looking at two regions of the country—one in Texas and another in the Pacific Northwest—to figure out where the best economic position is to put our first commercial facility,” Luce said, adding that the company is targeting an annual production output ranging between 5 MMgy and 25 MMgy. “We’re hoping if we stay on track with what we’re trying to do, then by the end of this year we’ll be breaking ground on either of those two sites for our first commercial facility.” _CheckBiotech

Houston—Terrabon, Inc., announced today that it has been successful in the production of an economical cellulosic gasoline fuel blend stock by leveraging CRI/Criterion’s renewable fuel catalyst technologies.

The use of catalysts are necessary to efficiently convert inedible feedstocks like garbage, sorghum, corn stover or woodchips into renewable cellulosic gasoline, diesel and jet fuel using Terrabon’s patented acid fermentation technology, MixAlco®.

These catalysts have enabled Terrabon to capture yield improvements from the MixAlco® acid fermentation process at its Bryan, Texas demonstration plant, known as Energy Independence I.

In fact, Terrabon actually exceeded the target yield threshold of 70 gallons of green gasoline per dry ton of garbage that it received from the cafeteria dumpsters and paper shredders at Texas A&M University.

Normally, this garbage would have been shipped to a landfill for disposal. _BiofuelsJournal

Seaweed is being viewed more widely as a valuable feedstock for biofuels production. Seaweed has many advantages over terrestrial biofuels crops -- including prolific growth rates, low lignin levels, and the ability to grow in salty and brackish water over most of the Earth's survace -- land and sea.

Japan is pushing ahead with 100% biomass-fired power plants. Torrefied biomass can be crushed and fired like coal. Gasification plants are preferable due the minimal waste resulting. Torrefied biomass -- either woody or grass -- can also be co-fired with coal with modifications to combustors. Biomass can also be co-fired with natural gas via gasification or pyrolysis -- using specially designed mixing chambers or nozzles and combustors.

Energy Bits and Pieces

University of Illinois researchers have altered the genome of Saccharomyces cerevisiae yeast in order for it to more efficiently ferment galactose as well as glucose. This allows for much higher yields of biofuel from the fermentation of highly prolific seaweed.

Researchers at the University of Wisconsin have isolated Saccharomyces cerevisiae strains possessing genes altered to make the yeast more tolerant of higher levels of alcohol. Such yeast will allow fermentation to proceed to higher alcohol concentrations, which can be more efficiently and economically separated from aqueous solution.

Amyris and Cosan are collaborating to produce base oils -- using modified yeasts capable of producing hydrocarbons from plant sugars. These base oils will be used to make high value lubricants for a wide range of industrial machinery and equipment.

Better methods of pyrolysis are being perfected to make profitable use of household plastic waste. Valuable products of such waste pyrolysis include fuels, plastics, lubricants, and char.

Pyrolytic recycling of old automobile tyres is becoming more popular. Valuable oils, gases, fuels, steel, and char products can be sold for a profit, rather than having the tyres buried in landfills or incinerated as waste.

The use of seaweed (and other halophytes) for fuels illustrates a significant expansion of productive surface area of Earth for biofuels production -- without using cropland or competing with food production. The use of waste materials to produce valuable fuels and materials illustrates the conceptual expansion of what is considered useful raw materials for profitable industries.

Coming $Multi-Trillion Industry to Disrupt Fossil Fuels In Time

Greg Mitchell, a researcher at the prestigious Scripps Institute of Oceanography, expects seaweed to become a multi-trillion dollar industry -- sometime after a ten year developmental period. This new industry should disrupt the use of fossil fuels, according to Mitchell.

According to the Biomass Handbook, cultivated seaweed can yield close to 130 tons per ha per year. Fast growing willow may yield just above 10 tonnes per ha per year. And miscanthus grass can yield 15 tonnes dry mass per ha per year. Giant King Grass (PDF) may produce 5 X or more yield than miscanthus, in tropical climates.

Those are rough figures which are subject to change as faster-growing strains are developed via several means. Besides rapid growth and 6 X a year harvesting, seaweed takes advantage of large areas of the Earth's surface which cannot be utilised to grow land trees or land grass for biomass. Seaweed essentially doubles available biomass growing area -- or more -- which throws conventional calculations for biomass potential out the window. Some problems must be worked out, but by the time humans truly need the massive quantities of biomass they can get from seaweed (and special grasses and trees), the problems should have been solved.

Seaweeds, a macro form of algae, hold great promise because of their potential for very high yields and high oil production while thriving on non-arable land. Another benefit is that they grow well in saline water. Traditionally crops will not excel in salt water and in some areas of the country valuable agricultural land has been taken out of production due to high concentrations of salt.

But as all researchers know, not all algae is created equal. There are strains of seaweeds that hold great promise for bio-energy and others that hold great promise for producing other products such as high protein meals for replacing non-sustainable ocean-caught fishmeals in aquaculture and other animal diets.

In fact, many algae companies that began with the mission of producing algal fuels have now refocused on producing algae products for the pharmaceutical, plastics, health, and agricultural feed industries. For example, there are strains of seaweeds that UCSD-SIO has been studying that grow well inland and can be used to recycle artificial seawater and waste nutrients from chicken ranches or pig farms. Algae has also been used in farm fish operations from cleaning the ponds to providing feed.

...Yet with all the research focused on algae, there are still several major hurdles that need to be overcome before algal biofuels will become commercially viable. The cost of production must be significantly reduced, elite strains of algae and seaweeds optimized for fuel production need to be developed and test facilities need to scale up to large production areas of several hundred acres.

Mitchell believes the timeline for this to occur spans more than 10 years. To date, all research projects are small and need to be brought to commercial scale levels. “We need several hundred acre demos that would take three years to design, permit and build. Then we need at least two years to get data and improve design,” said Mitchell. “Then we’ll roll out commercial scale over the following five years. We can do all this now at pilot scale but its not yet economically viable. So I see 10 years for this to be turned to economic viability.”

The result, Mitchell believes, will be a multi-trillion dollar industry that will disrupt the use of fossil fuels. _DomesticFuel

Biomass King Can Grow over 70% of Planet's Surface

The king of biomass is not switchgrass, miscanthus, or even micro-algae. The king of biomass is macro-algae -- seaweed.

A key trend from the Algae 2020 study finds most macro-algae projects prior to 2010 focused on ethanol. However, since 2010, the entrance of oil and petrochemical majors Dupont and Statoil are expressing an increased interest in extracting sugars from seaweed to create drop-in fuels, biochemicals and other valuable co products such as biobutanol. This follows a key trend by Shell and BP investing $12 and $8 billion respectively in sugar-based conglomerates in Brazil to produce bio-butanol, drop-in fuels, and bio-based chemical products.

Emerging Markets Online’s updated Algae 2020 study finds the surging investments in extracting sugars from seaweed follows an emerging microbial “sugar to biofuels” trend in the Americas in Brazil for ethanol, biobutanol, and advanced biofuels. In September 2010, Bunge and Chevron invested in US-based Solazyme to create renewable algae-based oils. In addition, LS9, Amyris, and Virent aim to use plant-based sugars to produce drop-in fuels,  bio-based diesel, biobutanol, biogasoline, biochemicals and bioplastics.

Will sea-based sugars from macro-algae provide a new feedstock for advanced biofuels, drop in fuels and biochemicals for these emerging sugar-based, infrastructure compatible biofuels and chemicals platforms? Evidently, an increasing number of petrochemical majors including Dupont, Statoil, believe harvesting sugars from seaweed is attractive and are investing in next-generation,sea-based macroalgae projects as a feedstock for advanced biofuels, drop-in fuels, biochemicals, and biopolymers.

_BiofuelsDigest

Emerging Trends in Macroalgae Investment

Project  and Partners	Products	Description
South Korea National Energy Ministry	Ethanol	Korea – $275 USD million project over 10 years to produce nearly 400 million gallons a year of ethanol by 2020, approximately 13% of S. Korea’s consumption. The project will create an offshore seaweed forest approximately 86,000 acres in size.
City of Venice JV with Port Authority and Electric Power Plant	Algae Biofuel for Electric Power	Italy – $200 million Euro project announced in March 2009 by the city of Venice to capture algae seaweed and generate 40 MW of power from algae biofuel to supply up to half of the city’s power supply and for to port facilities and docked ships in the harbor.  The project will also cultivate microalgae in closed photobioreactors to generate biomass for power generation.
Biomara / Scotland’s Ministry of Energy	Algal Biofuels	Scotland – $8 million USD from Scotland’s Energy Ministry and the EU’s INTERREG IVA Programme, and Crown Estate in April 2009 to investigate seaweed and microalgae strains for commercial scale production.
Chilean Economic Development Corporation (CORFO) and Bio-Architecture Lab (BAL)	Ethanol	Chile – $7 million USD investment in 2010 in a seaweed-based bio-ethanol project lead by US-based BAL in collaboration with Chilean oil company ENAP and the Universidad de Los.  Project goal is to replace 5% of Chile’s gasoline consumption with 165 million litres of ethanol.
Philippines National Government, Korean Institute for Industrial Technology.	Ethanol and biofuels	Philippines – $5 million from the Philippines government to develop a 250 acre, seaweed-based ethanol plant and aquafarm cluster. The aquafarms will in 4 locations and will utilize a South Korean ethanol extraction technology developed at the Korean Institute for Industrial Technology.
Statoil and Bio-Architecture Lab (BAL)	Ethanol and Co-Products (Lipids, Proteins, Iodine)	Norway – starting in late 2010, Statoil will fund  BAL’s  R&D and demonstrations projects in Norway with the goal of commercialization of BAL’s technology in Norway and in Europe.  BAL will utilize its process technology will convert seaweed from Statoil’s aquafarming operations into ethanol and co-products in the partnership.
Dupont/BAL  (Bio-Architechture Lab)	Biobutanol, Sugars for Advanced and Drop-In Fuels	USA – $9 million US-based Advanced Research Projects Administration Energy  announced in Spring 2010 to fund a DuPont/BAL macroalgae project  aimed at supplying biobutanol  to be marketed by Butamax, the BP-DuPont JV
Sources: Algae 2020 study Vol . 2, Biofuels Digest, Emerging Markets Online,  industry journals

Rapid growing, with frequent harvests, and capable of thriving in salt water -- the most abundant form of water on the planet -- seaweed has the capacity to out-mass any other form of biomass-to-fuels, biomass-to-electricity, and biomass to chemicals.

Wood to Syngas to Methanol, Plus Seaweed Ethanol

In Soperton, Georgia (USA), Range Fuels has instituted a multi-phase plan to produce methanol from wood and grass, which can then be used to produce biodiesel.

The first phase of the Soperton Plant operations employs Range Fuels’ two-step thermochemical process, which first gasifies non-food biomass such as woody biomass and grasses into syngas. In the second step, the syngas is passed over a proprietary catalyst to produce methanol, which can then be converted in an additional reactor to ethanol.

The Soperton Plant will initially use woody biomass from nearby timber operations, but plans to experiment with other types of renewable biomass as feedstock for the conversion process, including herbaceous feedstocks like miscanthus and switchgrass.

Range Fuels plans to expand the capacity of the plant to 60 million gallons of cellulosic biofuels annually with construction to begin next summer. The Soperton Plant is permitted to produce 100 million gallons of ethanol and methanol each year.

...During phase two of the project, currently slated for mid-2012, Range plans to expand production at the Soperton plant and transition from a methanol to a mixed alcohol catalyst, according to the EPA report. _GCC

As better catalysts to produce butanol from syngas are developed, the higher-value alcohol should come into more common use as a fuel additive for both gasoline and diesel.

Seaweed -- or macro-algae -- can be harvested up to 6 times a year, which makes it a very prolific form of biomass. It can be grown in salt-water ponds virtually anywhere the sun shines.

Scientists from Tohoku University and Tohoku Electric Power Co. have developed a technology to efficiently generate ethanol from seaweed such as sea tangle and sea grape, group members said Saturday.

The technology uses natural yeast discovered by the group as well as a new fermentation method, according to the group led by Minoru Sato, professor of marine biochemistry at Tohoku University _JapanTimes

Since seaweed is considered a pest weed in many areas, its use as a cash crop should spur economic development among a wide range of the socioeconomic strata. Japan is not the only country looking at seaweed as a biomass crop:

The idea of using seaweed for ethanol is also being researched in Korea and the Philippines, as well as in Chile. One of the benefits to using seaweed as an ethanol feedstock are that it grows quickly and allows for as much as six harvests per year. Also, since seaweeds do not have lignin, pretreatment is not necessary before converting them to fuels, making it potentially less expensive than other cellulosic sources._DomesticFuel

Ireland, Scotland, New Zealand, and a number of other maritime nations and island nations are also looking closely at the use of macro-algae for fuels, chemicals, plastics, feeds, and other products.

Seaweed to Biofuel: 6 (!) Harvests per Year !

The Earth is a biological planet. For that reason, the best way to make any chemical -- including fuels -- will be to use a biological approach. Large areas of the land surface can be used which are not suitable for growing food. But even more, the ocean itself can be used to grow abundant biomass for making chemicals and fuel. And the ocean can produce an abundant harvest indeed.

Now a group at the Korea Institute of Technology in South Korea has developed a way to use marine algae, or seaweed, to produce bioethanol and avoid taking up land altogether.

The group says seaweed has a number of advantages over land-based biomass. It grows much faster, allowing up to six harvests per year; unlike trees and plants, it does not contain lignin and so requires no pre-treatment before it can be turned into fuel; and it absorbs up to seven times as much carbon dioxide from the atmosphere as wood.

The group's patent suggests treating all sizes of algae - from large kelp to single-celled spirulina - with an enzyme to break them into simple sugars, which can then be fermented into ethanol.

The resulting seaweed biofuel is cheaper and simpler to produce than crop or wood-based fuels, and will have no effect on the price of food, says the group. _NS

Of course you can make other fuels such as butanol, jet fuel, diesel, gasoline . . . . All you need is the right catalysts and either a gasification plant or a pyrolysis plant (or both). You can make plastics, solvents, or program the algae to make valuable pharmaceuticals or other commercial products.

The only thing that threatens the human enterprise on this planet is bad leadership, and unfortunately we have a bumper crop of that.

Ireland and New Zealand: Seaweed Leaders?

Island nations, Ireland and New Zealand, are located almost precisely diagonally half a world apart from each other--both North and South, and East and West. Interestingly, both Ireland and New Zealand are looking at ways of making a common natural resource--seaweed--an increasingly profitable enterprise. Seaweed is a type of multi-cellular algae that can be quite prolific in areas where other plant life is scarce.

'Compared to other bioenergy crops (eg rapeseed, canola, peanut, oil palm) there are a number of species of algae that have higher areal productivities, higher oil content and that can grow in saline waters.

'These apparently very favourable properties have generated a frenzy of interest and activities in the field of energy production using algae, both microalgae and seaweeds.'

He continued, 'For biofuel production the algal biomass needs to be produced at a cost of around $US1 or less per kg. In order to achieve this ambitious goal there is the need for year-round reliable high productivity algal culture and all factors (eg, algae strains, algae culture, harvesting and further downstream processing) need to be optimised and efficiently integrated.'

Ireland boasts 16 commercially useful seaweed species, with additional species being added as more research is carried out. Ireland's location off Western Europe, surrounded by clean seas, is a major selling point to the world market. __BioenergyCheckBiotech

New Zealand also has a long tradition of seaweed cultivation, and Air New Zealand is one of the airlines looking at seaweed, algae, and oil seeds to fuel their fleet.

Most likely, to replace petro-fuels with biofuels, it will be necessary to use significant areas of both land and ocean for growing fuel crops--until advanced synthetic biology finds ways to boost bio-production far beyond current known limits.

Japan, Korea, and China are other countries making use of extensive seaweed cultivation. But coastlines alone may not be enough. As discussed previously, artificial islands or seasteads may become important "ocean farms" for production of bio-energy--turning vast regions of mid-ocean "deserts" into scattered oasis, teeming with useful life.

Mariculture Biofuels--Seaweed to the Rescue!

The oceans of Earth are considered the birthplace of life. Oceans receive most of the sunlight and absorb and convert most of the CO2 produced by nature--including humans. Now mariculturists are experimenting with seaweed a partial solution to the world's energy price crisis. Understand? Sunlight plus CO2, a priceless combination for plant life.

The oceans are the largest active carbon sink on the planet, covering more than 70 per cent of its surface area, and are predicted to grow as sea levels rise. Our seas also receive a larger proportion of the world's sunshine than land does, particularly in the tropical and subtropical belt where land is scarcer.

To agriculturalists, the oceans are vast and grossly underused fields well provided with sunlight and water.

...In Costa Rica and Japan, seaweed farming has been re-established to produce energy. It can quickly yield large amounts of carbon-neutral biomass, which can be burnt to generate electricity. High-value compounds — including some for other biofuels — can be extracted beforehand.

We have calculated that less than three per cent of the world's oceans — that's about 20 per cent of the land area currently used in agriculture — would be needed to fully substitute for fossil fuels. A small fraction of that sea area would be enough to fully substitute for biofuel production on land.
_CheckbiotechBioenergy

Three percent of the world's oceans to fully substitute for fossil fuels? What about using seasteads as centers of mariculture, in addition to all the other renewable energies they will utilise?

How difficult would it be to create an oasis of sea life on the normally life-depleted "desert" of the high seas? Most sea life lives along island and continental shores, and continental shelves and seamounts. What could a serious movement into seasteads do toward expanding life in the oceans?