Deep Ocean Water for Carbon Removal

Posted in Algae by Robert Tulip on the September 27th, 2017

Proposals to raise deep ocean water (DOW) to the surface as a climate mitigation technology have been criticised for producing warming. These problems may not arise if DOW is used for algae production with full recycling of nutrients.

Atmospheric consequences of disruption of the ocean thermocline, (Kwiatkowski et al 2015 Environ. Res. Lett. 10 034016) found that artificial vertical mixing of ocean water for local cooling, such as in the proposed ‘Lovelock Pipes’, would actually produce wider warming, reversing the intended benefit. Any proposed applications of large scale ocean pumping to mitigate climate change would need to address the problems modelled by this and related studies.

In considering use of ocean pumping for large scale algae production, recycling of deep ocean nutrients may be a key method to address such problems. A recent scientific paper, Phosphorus and nitrogen recycle following algal bio-crude production via continuous hydrothermal liquefaction, ( Edmundson, S., Algal Research (2017), http://dx.doi.org/10.1016/j.algal.2017.07.016), explains how hydrothermal liquefaction (HTL) to produce algae biocrude can separate and recycle the phosphorus and nitrogen in algae for ongoing reuse as fertilizer.

This finding could enable ocean based algae production to mitigate climate change by recycling oceanic phosphorus and nitrogen in combination with carbon dioxide mined from the air. Subject to modelling assessment, my hypothesis is that the climate benefit of efficient removal of carbon from the air in this way would outweigh any warming effects.

If nitrogen and phosphorus from deep ocean water are used to fertilize a contained algae pond at sea, and the algae is then converted to biocrude by HTL, then the finding that phosphorus and nitrogen in the algae can be separated from the biocrude enables continuous reuse of these nutrients. This changes the parameters for analysis of deep ocean water climate impact. Recycling of oceanic nutrients in algae farms presents a possible path to enable efficient mining of carbon from the air at scale.

If nutrients can be used in combination with atmospheric CO2 for ongoing repeat fertilization of the algae farm, this HTL nutrient separation process means DOW could potentially provide the nutrients required to grow algae on the scale needed to reverse global warming.

For algae factories at sea using HTL and recycling nutrients, my calculations of orders of magnitude are as follows.
· Ocean water below the thermocline has 3 micromoles of phosphate per litre, equal to 90 tonnes of phosphorus per cubic kilometre (per Sverdrup).
· The scale of carbon removal to reverse climate change requires removal of more than the ten gigatons of carbon in CO2 added to the air every year.
· To push back from the brink of possible climate tipping points, a reasonable goal is to remove twenty gigatons (petagrams) of carbon from the air every year (one gigaton of water has volume one cubic kilometre).
· Converting twenty gigatons of carbon from CO2 to hydrocarbons and other products for storage in stable useful form (plastic, soil, bricks, roads, etc) would require 172 million tonnes of phosphorus and 2.6 billion tonnes of nitrogen to grow algae at the Redfield Ratio (C:N:P=117:14:1).
· With complete retention of mined phosphorus and nitrogen via HTL, about two million cubic kilometres of water would need to be processed to obtain that amount of nutrient.

The attached diagram of a tidal pump may be one way to shift this volume of water. For the entire annual goal of 20gt of carbon, my estimate is that pumping arrays of 500,000 km2 located on continental shelves with twice daily tidal range 0.5 metres would take ten years to pump two million km3 of water to the surface, in order to mine the required amount of phosphorus and nitrogen from deep ocean water.

These nutrients would then be available for permanent recycling. This process would also deliver other useful dissolved minerals, and would continue indefinitely, enabling economic use of the vast dissolved mineral wealth of the seas. That scale of pumping operation is about 2% of the world continental shelf area as an eventual goal, and would depend on the availability of suitable locations, which in turn would depend on demonstrated environmental benefit. The algae farm area would be about six million km2, or 2% of the world ocean surface.

The use of hydrothermal liquefaction at such a scale would require innovative technology. HTL requires pressure equal to water pressure at two kilometres deep in the ocean, and temperature above 300°C, to make the algae cell wall break down to produce biocrude. The best way to subject algae slurry to such heat and pressure may be to pump it down to the deep ocean floor, and develop controlled automated sea floor systems for processing, as per the attached sketch. The feasibility of that method has not been assessed.

In summary, the demonstration that ‘Lovelock Pipes’ would have unforeseen warming effects does not mean raising DOW is unfeasible as a climate change response, and the ability to use HTL to recycle oceanic nutrients means that large scale ocean based algae production could be an effective method for carbon mining to deliver climate stability.

Robert Tulip

Ocean current transport and storage

Posted in Algae by Robert Tulip on the December 29th, 2015

From http://cosmoquest.org/forum/showthread.php?155963-Submarine-Buoyancy&p=2333327#post2333327

Ocean current transport and storage could be safer and more economic and scalable than storage of carbon products on or beneath the land.  The attached diagram shows a route to move algae grown in the tropics to polar seas using deep ocean currents.

Ocean Current Algae Transport Storage

The large ocean currents are the circulation system of our planet, akin to the veins and arteries of blood circulation of a body.  Fossil emissions are like cholesterol in the arteries of the world ocean, potentially causing disruption of the entire system.  The immediate global climate challenge is to remove more carbon from the air and sea than we add, in order to restore climate stability and insure against massive sudden change.

The stable ocean currents can be used as transport and storage systems for algae, beginning at small scale to test safety and efficacy, possibly using bags containing fresh water, and building upon scientific knowledge of ocean current size and behavior [url]https://www.whoi.edu/main/topic/ocean-circulation[/url].

Growing algae in large bags in the Pacific Ocean at the equator can be a way to utilize the global ocean currents for energy, nutrient and space to contribute to climate stabilization. By sinking produced contained algae blooms to the ocean floor using tidal pumping or other methods, and applying heat and pressure, the algae can be concentrated and converted to useful commodities including oil and bioplastics.  Products such as oil can then be transported in bags made of bioplastic on the deep ocean subsurface currents, if these bags can be proven to be safe and effective.

There are many problems which could prevent this idea from working.  It is entirely new and innovative, a research concept rather than an active proposal. The scale of the Antarctic Circumpolar Current, as the core of the stable planetary ocean circulation system combined with the other main oceans, gives potential for this method to be a major effective contribution to carbon removal, utilization and storage. Using the existing energy systems of planetary currents to mine carbon could be important to maintain the health and stability of the global ocean circulation system.

The current California methane leak [url]http://www.zerohedge.com/news/2015-12-24/unstoppable-california-gas-leak-now-being-called-worst-catastrophe-bp-spill[/url] illustrates the risks of geostorage, especially where other mining occurs nearby.

The whole range of storage possibilities should be explored, to find the products from algae that can best substitute for existing methods, addressing carbon capture, storage and utilization.  Sequestering carbon into the ocean in stable and valuable form could mobilize the investment resources needed to scale and sustain action to deliver the Paris Leaders Agreement on Negative Emission Technology.

This Planet Accord is implied in Paris Agreement [url]http://unfccc.int/resource/docs/2015/cop21/eng/l09r01.pdf[/url] Article 5 1. “Parties should take action to conserve and enhance, as appropriate, sinks and reservoirs of greenhouse gases…” The ocean is easily the largest carbon sink for the planet, dwarfing the scale of land based alternatives.  Industrial systems could build carbon sinks in the ocean using algae manufacture and storage.

An algae based economy

Posted in Algae by Robert Tulip on the November 2nd, 2015

Planetary transformation should be to different methods of consumption that can sustain and increase human wealth and happiness.   In terms of the climate crisis, thinking on emission reduction needs to evolve into a new paradigm for a transformed ethic of human existence on our planet. The strain on world resources will only be managed through focus on technological transformation.

How I visualise a transformed world is one where the massive unused resources and energy of the world ocean become available through new simple large scale technology, and as a result the grossly inefficient traditional rural systems that perpetuate poverty and impact the environment can be replaced by new modern urban lifestyles in which people have a light ecological footprint but still have abundant energy and resources.

A shift to a high technology urban lifestyle, with materials mainly built from carbon, can create universal abundance for high human populations while also enhancing global biodiversity.  Failing to explore such a path leaves open the risk of catastrophe.

Current affluent lifestyles are not sustainable and replicable in the manner of the First World.   It is actually possible physically on our planet to shift the world economy to a system of abundance rather than scarcity, but this needs a paradigm shift in terms of both technology and culture.

My view is that it is entirely physically possible to achieve sustained global abundance through an algae based economy.  This is not an irresponsible fantasy but a practical reform agenda.  Putting our eggs in the basket of sacrificing wealth by reducing energy and resource use is actually the really irresponsible attitude, since it is a recipe for failure and conflict, whereas discussion of a technological path to universal abundance is a basis for successful stable global peace and justice.  The environmentalist ideology is a genuine barrier to progress when it stymies technological solutions.

We need to shift from a linear waste mentality to a culture of cyclic reuse. Such a shift could sustain vastly higher productivity and happiness than we now have.

My point here is counter-intuitive from a traditional linear view.  We naturally assume that the most wealthy cause the most damage.  But that ignores the role of education as a product of wealth in enabling biodiversity protection by improving understanding and accountability.  Among the real causes of biodiversity loss, one of the biggest factors is poverty, for example in the use of firewood for cooking and in activities of subsistence farmers to clear land.

I propose as a core reform to develop efficient industrial processes to grow algae on immense commercial scale at sea.   The results of that would be immediate direct protection of marine biodiversity by increasing the nutrient available at the base of the food chain, and also by stabilising the carbon cycle, enabling rapid removal of the excess carbon our linear methods have added to the air and water.

We need an unbending focus on the big picture, which is the question of how we can mine twenty billion tonnes of carbon from the air and sea each year.

Summarised from http://www.booktalk.org/post152003.html#p152003