NASA scientists are proposing algae bags as a way to produce renewable energy that does not compete with agriculture for land or fresh water. It uses algae to produce biofuel from sewage, using nutrients from waste water that would otherwise be dumped and contribute to pollution and dead zones in the sea.
Why Algae? Some types of algae can produce at least 2,000 gallons of oil per acre per year. Jonathan Trent, lead research scientist on the Spaceship Earth project at NASA Ames Research Center, Moffett Field, California, says: “In fact, most of the oil we are now getting out of the ground comes from algae that lived millions of years ago. Algae are still the best source of oil we know."
Trent envisages large plastic bags floating on the ocean. The bags are filled with sewage on which algae feed. The transparent bags collect sunlight that is used by the algae to produce oxygen by means of photosynthesis. The ocean water helps maintain the temperature inside the bags at acceptable levels, while the ocean's waves also keep the system mixed and active.
The bags will be made of “forward-osmosis membranes”, i.e. semi-permeable membranes that allow fresh water to flow out into the ocean, while preventing salt from entering and diluting the fresh water inside the bag. Making the water run one way will retain the algae and nutrients inside the bags. Through osmosis, the bags will also absorb carbon dioxide from the air, while releasing oxygen. NASA is testing these membranes for recycling dirty water on future long-duration space missions.
As the sewage is processed, the algae grow rich, fatty cells that are loaded with oil. The oil can be harvested and used, e.g., to power vehicles.
In case a bag breaks, it won’t contaminate the local environment, i.e. leakage won't cause any worse pollution than when sewage is directly dumped into the ocean, as happens now. Exposed to salt, the fresh water algae will quickly die in the ocean.
The bags are expected to last two years, and will be recycled afterwards. The plastic material may be used as plastic mulch, or possibly as a solid amendment in fields to retain moisture.
The algae may also be harvested and processed to produce food, constituting another cycle of a sustainable economy, as pictured below.
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Comments: 21
Algae seems to be an extremely versatile resource. It could also be used to neutralize CO2 emissions from coal plants - at a net profit. The product from such an operation could be used for biofuel or a health drink, which your article also suggests.
Not only do you harvest oil from the algae, you clean up the ocean. The algae removes carbon from the atmosphere, and (if I'm reading this right) could also produce fresh water from salt water.
Forgive me for not looking this up, but what's the state of clean-coal proposals? Is that viable? What are the costs of coal exhaust sequestration?
The following species listed are currently being studied for their suitability as a mass-oil producing crop, across various locations worldwide[35][36][37]:
* Botryococcus braunii
* Chlorella
* Dunaliella tertiolecta
* Gracilaria
* Pleurochrysis carterae (also called CCMP647)[38] .
* Sargassum, with 10 times the output volume of Gracilaria.[39]
Algae Fuel
In the NASA article, the bags are described as inexpensive plastic bags. There's no need for land, water, fertilizers, etc. The infrastructure to pump sewage to the sea is already in place. Algae can grow 20 to 30 times faster than food crops. Economically, the proposal looks sound, even before taking into account the environmental benefits.
I don't see technical hurdles either. Aircraft can fly on algae oil. Back in Jan 7, 2009, a Continental Airlines commercial aircraft (a Boeing 737-800) was powered in part by algae oil, supplied by Sapphire Energy. The main hurdle seems to be that algae oil is not perceived as price-competitive with fossil fuel-based jet fuel.
Taken on its own, each of these processes may be perceived to be too expensive. But each of them may help make the entire cycle in the bigger picture become more economic, while the cycle as a whole has additional environmental benefits that aren't currently incorporated in the price. With innovation and economies of scale, prices can eventually come down to levels that even such feebates won't be necessary and they will phase themselves out.
10% of the land mass of N. Mexico, dedicated to production of algae biofuel, would produce all of the transportation fuel needed in the U.S.
Let me add a few more paragraphs on funding. By comparison, a 2007 Bloomberg report estimated that the Gulf of Mexico's Dead Zone would reach more than half the size of Maryland that year and stretch into waters off Texas. The Dead Zone endangers a $2.6 billion-a-year fishing industry. The number of shrimp fishermen licensed in Louisiana has declined 40% since 2001. Meanwhile, U.S. farmers in the 2007 spring planted the most acreage with corn since 1944, due to demand for ethanol. As the report further describes, the Dead Zone is fueled by nitrogen and other nutrients pouring into the Gulf, and corn in particular contributes to this as it uses more nitrogen-based fertilizer than crops such as soybeans.
According to zFacts.com, corn ethanol subsidies totaled $7.0 billion in 2006 for 4.9 billion gallons of ethanol. That's $1.45 per gallon of ethanol (or $2.21 per gallon of gas replaced). As zFacts.com explains, besides failing to help with greenhouse gases and having serious environmental problems, corn ethanol subsidies are very expensive, and the political backlash in the next few years, as production and subsidies double, will damage the effort to curb global warming.
At UN climate talks in Bonn, the world's poorest nations proposed a levy of about $6 on every flight to help them adapt to climate change. Benito Müller, environment director of the Oxford Institute for Energy Studies and author of the proposal, said that air freight was deliberately not included. The levy could raise up to $10 billion per year and would increase the average price of an international long-haul fare by less than 1% for standard class passengers, but up to $62 for people traveling first class.
In the light of those amounts, it doesn't seems unreasonable to expect that fees imposed on conventional jet fuel could raise billions per year. Proceeds could then be used to fund algae bags and air capture of carbon dioxide, which could be pumped into the bags on location to enhance algae growth. With the help of rebates, the infrastructure to grow algae in such bags could be set up quickly, helping the environment, creating job opportunities, making the US less dependent on oil imports, while leaving us with more land and water to grow food, resulting in lower food prices. Importantly, that would also help with the development of air capture of carbon dioxide, which is an essential part of the blueprint to reduce carbon dioxide to acceptable levels.
The picture below indicates how fees on aviation could assist with the development of floating algae bags.
As the picture indicates, proceeds could be used to fund air capture of carbon dioxide, and the CO2 thus captured could be pumped into the bags in an arrangement that is financially attractive to the development of algae bags. Fuel processing facilities on location could then use both the CO2 and the algae to produce biofuel, which would in turn be used by aviation.
Bags would reduce the amounts of nutrients that reach the water and that make the microscopic organisms in the water grow. Bags could also reduce the amounts of sunlight penetrating the water, since the bags cover the surface of the water. In conclusion, there will be less of those organisms if bags are installed. In areas referred to as dead zones, that would be good, since excess amounts of micro organisms cause oxygen depletion, suffocating fish and shrimp. Also, in the case of dead zones, bags wouldn't reduce light penetrating the water, since the water is already pretty much covered by bloom anyway. Yet, I can imagine that some balance could be found, where bags cover only parts of the seashore, while some sewage would still reach the water and stimulate growth of micro-organisms.
Since the bags are filled with fresh water from sewage, the algae grown in the bags will be fresh water algae. In case some of these fresh water algae would escape from the bag, they would be exposed to salt from the sea and will quickly die.
Even if released in fresh water, I don't expect much harm, since the algae in the bags will be strains that feed on very nutrient-rich water and that are non-toxic. By contrast, some of the native algae are toxic and can cause tumors. Boiling the water will not destroy the toxins - it will kill algae but in doing so will release toxins into the water. In fact some toxins become more dangerous as a result of boiling the water.
Of course, anything that grows somewhere will compete with anything else that could grow there. The algae in the bags will compete with the aquatic vegetation or phytoplankton in that area. Currently, however, excess amounts of phytoplankton, showing up as algal blooms, do cause a variety of problems including lack of oxygen in the water, choking fish and shellfish. As said, I can imagine that some balance could be found, where bags cover only parts of the seashore, while some sewage would still reach the water and stimulate growth of aquatic vegetation.
Air capture devices could be powered by surplus energy from offshore wind turbines. With the help of such funding, the entire infrastructure could be set up quickly, helping the environment, creating job opportunities, making the US less dependent on oil imports, while leaving us with more land and water to grow food, resulting in lower food prices.
I agree with Leo, so many new things never get tried. Sounds like a wonderful way to obtain oil and recycle waste.