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Tidal Pump by Robert Tulip

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The Tidal Pump, now at proof of concept, aims to shift large volumes of liquid in the ocean at lowest possible cost using new technology.



The Tidal Pump has six components: a Float, Tether, Weight, Bladder, Inlet and Outlet.  The Float is an air-filled balloon that moves with the tide.  The Tether holds the Float to the Weight, a cylinder of ballast, above the Bladder on the ocean floor.  On a rising tide, the Float lifts the Weight causing the Bladder to fill with liquid from the Inlet.  On a falling tide, the Weight sinks, expelling liquid from the Bladder through the Outlet. This use of vertical tidal motion can be augmented by use of tidal currents driven by turbines.

A balloon as the Float of 20 metres diameter and volume 3800 m3 would carry a Weight of sand of 10,000 tonnes.  The float has to be partly above the ocean surface to deliver pumping power, so the weight has to be less than that.  Such an anchored floating island can also have other uses.  Analysis and modelling will assess feasibility, design, efficiency, costs, materials, uses and risks.   The Tidal Pump aims for cost advantage over existing pumping methods.  In an algae biofuel system, tidal power can pump liquids at all stages of the process, raising high nutrient water to the surface from the deep ocean, moving liquids through an algae pond on the surface, and pumping algae slurry into a hydrothermal liquefaction chamber at depth for oil extraction.

The Tidal Pump concept is part of a proposal for Public Private Partnership with the Gorgon Liquefied Natural Gas Project Joint Venture partners Chevron, Shell and ExxonMobil on Australia’s North West Shelf to make algae, to market waste carbon as fuel, food, fertilizer and fabric, as a better use than planned CO2 geosequestration.  Splitting the CO2 molecule through algae production can fund new negative emission technology to remove carbon from the atmosphere at scale.  Scaling up to a sizable part of the world ocean presents new frontiers for methods to mine carbon as a key to drive CO2 levels down to stable Holocene levels by removing more carbon from the air and sea than we add.

What actions do you propose?

Actions for the Tidal Pump start with proof of concept and extend to the strategic contribution to climate stability through carbon dioxide removal. The tidal pump requires analysis by engineers and scientists to assess feasibility and design. It may prove unfeasible on cost grounds (I don’t think so), or it may start a multi-billion dollar transformative global industry. Once the science is done on design feasibility, the search for locations, partners and pathways can proceed.

Diagrams at illustrate the proposal

1.    Regional Ocean Algae Project Map

2.    Detail Ocean Algae Project Map

3.    Balloon Sand Tidal Pump Diagram

4.    Australia Tides

5.    Deep Sea Nutrient Chart

6.    Tidal Pump Schematic

7.    Tide Range North West Shelf

The Tidal Pump is the first step for a project on algae biofuel production, supporting global security interests in energy, food, water, commerce and climate. The project aims to reduce algae costs and increase yield, eventually becoming self-funding by producing food, fuel, feed, fish, fertilizer and fabric. Solving the physical and economic constraints of algae production will enable the energy-water nexus to drive response to climate change.

Aiming to use technology that relies entirely on the resources of the sea, with industrial processes that are environmentally beneficial, automated and self-replicating, the tidal pump is part of a technology research agenda to bring algae biofuel to market. The project aims to develop new negative emission technologies through a Public Private Partnership with the gas industry. This will enable new policies, changes in economic incentives and evolution of behavioral norms to encourage adoption of physical actions with direct impact on climate change through a suite of new technologies. 

A key question is whether tidal pumps can compete on cost against conventional electric and diesel pumps. The high capital cost relative to conventional pumping aims to be recovered by low operating cost at scale, with size eventually only limited by the available ocean area. Tide pump systems could be many square kilometres in area, if ecologically and economically justified. In a tidal range of one metre, a square kilometre system would pump one gigalitre per tide, minus loss from fluid dynamics. Quantifying this loss and optimising design is the next main step.

A linked set of innovations together point to a new technological paradigm that will be cost competitive. Energy from ocean tide, current, wave, sun, wind, geothermal and ocean thermal sources can move and process CO2, nutrient, algae and water on large scale at low cost. Co-location with offshore gas projects can use their CO2, capital, resources and expertise, while developing methods suitable for wider deployment. Hydrothermal liquefaction at the sea floor could be the best way to extract algae oil. Produced algae can be the feedstock to make more algae factories using bioplastic. These methods aim to drive down capital and operating costs to compete against fossil fuels when replicated and expanded to achieve efficiencies of scale. Aims include automation, low cost inputs, development of high yielding varieties and production methods, methods to sink the entire system temporarily during storms, location in places with beneficial impact on large scale, and design to reflect sunlight back to space to help cool the sea and reduce storm intensity. Deep sea locations may need to be driven by wave rather than tide. Other applications for tidal pumping include desalination, floating islands for waste water treatment and industrial and transport platforms, and fixing ocean dead zones and protecting habitats such as coral reefs by removing nutrient, acid and heat from the water.

The MIT Colab process can have an essential feasibility role in mobilising expert testing and advice for proof of concept. Analysis should consider technical and commercial feasibility and links, environmental risks and institutional structures. Algae biofuel and tidal power are already the subject of major commercial research programs. Feasibility analysis requires strong regulatory risk frameworks. Powers and rights relating to use of areas of ocean involve local and national authorities especially for regulation of impact on fishing, shipping and the natural environment.

Next steps are building a model tidal pump and quantifying physical forces to show if and how the concept works in terms of fluid mechanics, materials and design, and then defining the critical path through to broad implications for the energy-water nexus and climate change. The material and structural design feasibility of the tidal pump needs to be proved first. As I have developed this concept, my design assumptions have evolved. A balloon float and a sand weight will maximise power and minimise cost. The vertical lift of this system has to be augmented by tapping the horizontal flow of tidal water as already used for electricity production by firms such as Green Tide Turbines and the design needs to recognise main precedents such as Carnegie Wave. I am now building a model tidal pump which I will document, including quantifying the physics. The only moving parts are the overall tidal shift up and down and the opening and closing of inlet and outlet valves in response to water pressure.

Ocean processing of algae has big advantages compared to working on land, including available space, resources and energy, and ecological benefits. Challenges include storm, remoteness and method of design of new technology. Ecological impact aims to be a major positive. Location, design and materials have to be developed on the basis of ecological analysis. Deep ocean processing can be approached incrementally, recognising that this research field has not moved much beyond concept. Hydrothermal liquefaction at depth, discussed in the attached paper, is emerging as a deal changer for algae biofuel compared to drying and solvent extraction. Algae experts at Australia’s CSIRO with whom I discussed this proposal saw the HTL concept as particularly interesting. The tidal pump is well suited to algae processing in shallow sheltered waters as envisaged by the NASA OMEGA Project. Design and risk analysis for ocean deployment has to be based on extensive practical lessons of pilot operation.

Political or policy challenges that this project could face include acceptance of negative emission technology, questions about risk, and impact on fossil fuel emission control. In itself, tidal pumping is a simple technological innovation which should be progressed in pilot locations with local environmental permits, following laboratory proof of design. Scaling up will require complex scientific analysis of impacts on ecology and hydrology.

The idea that algae farming could eventually fix more carbon than total human emissions produces a political challenge to thinking on climate policy. Emission reduction as such could prove to be a second order solution compared to sequestration of carbon in useful infrastructure made from algae. If the construction sector can use 20 billion tonnes of carbon per year mined from algae for roads and buildings, that would be double total emissions, and the total carbon load in the air and sea would reduce to stable levels within decades. By contrast, current emission reduction proposals see addition of 8 (?) billion more tonnes of carbon to the air each year as wildly ambitious, despite its risk of dangerous instability in the global climate. This policy disconnect warrants examination of the fundamental issues at stake.

Algae farms powered by tidal pumps on 2% of the world ocean could remove more carbon from the air and sea than total human emissions. The opportunity this could provide for a fundamental rethink of strategies for climate stability, and potential of this technology to enable regulation of the atmosphere, offer policy challenges which are already the subject of debate in the broad context of carbon dioxide removal as a climate strategy, as indirectly noted by the IPCC.

If coal fired power stations could recycle their waste carbon using high efficiency low emission technology linked by pipelines to algae farms, this could enhance their efficiency and safety, reducing the need for decarbonisation of the economy and enabling sustainable fossil fuel extraction. This observation confronts the political view that emission reduction is an end in itself, even though emission reduction alone is not able to stabilise the climate, but only slows the arrival of a dangerous tipping point while we buy time for new technology such as algae biofuel.

An advantage of tidal powered algae over other renewable energy sources is that it does not require structural metal. The floating algae farm and the tidal pump are entirely made of carbon based plastic.  They do not produce major emissions in their construction or operation, and do not compete for scarce resources or land.

Carbon Dioxide Removal as a primary climate strategy faces tension with calls for decarbonisation of the economy. I disagree with the decarbonisation concept, because fossil fuel use can be sustained by recycling its waste carbon for profit, with transparent focus on science and ethics. Building algae farms on two percent of the world ocean can remove more carbon than we add in ways that build upon the value of existing hydrocarbon infrastructure and investment with broad economic and environmental co-benefits.

Western Australia is the best place to start, with base in Perth linked to scientists and businesses, and the North West Shelf for implementation. Tidal pumping can be developed with the liquefied natural gas (LNG) industry to pump nutrient-rich water from deep in the Timor Trench up to the surface to fuel controlled algal blooms turbocharged by use of LNG CO2 emissions. Piloting on the Northwest Shelf can partner with the $50b Gorgon and the $34b Ichthys Joint Venture projects (map). This location has suitable shallow warm calm seas. Public private partnerships with the Gorgon JV firms Chevron, Shell and ExxonMobil and Ichthys JV firms Inpex and Total can use as algae feedstock the 3000 tonnes of CO2 that the Gorgon LNG project plans to geosequester every day. The gas industry has resources, locations, skills, capital, will, need and influence that could make this project happen fast, as a profitable way to turn the fossil fuel industry from climate wreckers to climate savers.

Tidal pumping has high potential in areas of high population and pollution such as the Yellow Sea between China and Korea, where the high tidal range and high nutrient load could enable the methods described here to be used commercially for environmental rehabilitation.

Location should start with desk and laboratory modelling, then in sheltered bays before ocean trials, to define structure and materials and to create a critical path for deployment. A tidal pumping array on the edge of a continental shelf could raise high-nutrient water from the deep to the ocean surface. This Map of world tides helps show potential locations.

Commercial viability is key to compete with fossil fuels. To identify and address main cost factors that now make algae production uncompetitive will deliver a profit driver for system replication and rapid expansion through sale of produced commodities. Simple and robust design with few moving parts minimises operation and maintenance costs.

The attached paper discusses climate benefits. The broad climate benefit rests in the plan to eventually mine carbon directly from the atmosphere, with potential to drive reduction of the carbon load back down to the stable Holocene level of 280 ppm this century, mitigating risks including extinction, acidification, sea level rise, increased storm intensity and temperature rise.

Who will take these actions?

Algae carbon dioxide removal at sea can become an attractive venture capital investment opportunity that energy companies, pension funds, aid donors and the military should support.  Ocean based algae production can deliver energy security in a way that will enable diversification of supply locations and sustained protection of the stock price of fossil fuel companies against climate related risks, an agenda of strong strategic and economic interest.  This environmentally sustainable energy production method also offers ethical and reputational benefits and social licence by providing positive externalities.

These ideas require assessment by an organisation with standing, capacity and focus on the public good which can broker relationships with the energy industry, partnering with companies such as Chevron, Shell, Exxon, Inpex and Total through their LNG projects in Australia.  These proposals are directly relevant to World Bank programs such as the Public Private Infrastructure Advisory Facility, the Energy Sector Management Advisory Program and the Global Gas Flaring Reduction Public-Private Partnership.

Ocean based algae farming can become a method for developing countries to increase economic growth and participate in trade, generating energy, food, revenue and jobs while protecting the environment and the climate. Industry partners are needed because public sectors alone cannot mobilise the capital, skills and resources needed to deliver such a large scale innovative profit driven project.  Development of ocean based algae production needs multi-stakeholder engagement to convene and mobilise a business plan.  If initial analysis proves positive, private industry can invest money, expertise and resources, while governments can bring regulatory systems, seed funding, expert analysis, community engagement and political will.  

Where will these actions be taken?

Algae biofuel is not yet profitable, primarily because of space, energy and input costs for land-based methods.  Shifting production to the ocean could address these problems, aiming for locations with waste CO2 such as the Gorgon and Ichthys LNG projects in Western Australia. 

Following laboratory proof of concept for safety and efficacy, testing in sheltered bays can optimise methods and materials for scaling up. 

The eventual goal is to make the vast ocean deserts productive. 

Algae farms can provide environmental services through local insurance against climate change, severe weather events and pollution.

Location near coral reefs and river mouths would reduce the heat and acid and nutrient loads that are now placing pressure on these ecosystems, as a climate response with high benefit.  Australia’s Great Barrier Reef and the Mississippi Delta should be considered as primary potential locations to clean up damaged and potentially threatened environments.

The ecological benefits of cooling and cleaning local water and factors such as access to nutrient sources, storm risk and remoteness have to be balanced against any possible negative impacts on water flow, shipping and ecosystems for site selection.

How will these actions have a high impact in addressing climate change?

Algae farms at sea could in theory remove one tonne of carbon per hectare per day, orders of magnitude above the rate possible from forests on land.  Algae yield can be scaled up in ocean locations that do not compete with agriculture or ecological habitat but rather have positive environmental impact.  At this unit yield, algae farms on 3 million square kilometres would hypothetically remove the same amount of carbon as added by all emissions.  Removing an amount equal to all added carbon would involve algae farms on 1% of the world ocean, if yield projections can be achieved and all produced algae is stored. If half the produced algae is used as fuel, the area required for algae farms to sequester as much carbon as all global emissions would be about 2% of the world ocean.  The scale of the oceans means there are enough suitable locations, especially considering the environmental co-benefits to endangered places such as coral reefs. 


What are other key benefits?

Carbon from algae production is economically useful as food or fuel, stored in a strategic petroleum reserve, or sequestered in infrastructure such as roads and buildings in forms such as bioplastic and bitumen.  Storage of mined carbon would remove added carbon from the air.  Bituminous products from algae oil used in road works presents one potentially major sequestration opportunity.  Bioplastic made from produced algae oil should be the main constituent of algae farm membranes and pipes. Existing methods and firms could adapt and evolve to an emerging stable climate economy, maintaining the social, economic and ecological sustainability of fossil fuel extraction.  Such a shift would protect global and local ecology, enabling sustainable development.  Algae farming can be a Negative Emission Technology through biofuel, infrastructure, biochar, fabric construction and fisheries.


What are the proposal’s costs?

This proposal aims to be commercially profitable, through technology that will pay for itself while mitigating climate change by aiming eventually to remove more carbon from the air and sea than total emissions. The overall aim is to drive down CO2 to the stable historic level of 280 ppm, and therefore avoid the massive likely costs of a climate tipping point crisis. Initial private seed capital is required for research and development, alongside regulatory oversight and risk analysis from scientific experts funded by governments, universities and international agencies.

Desk analysis of the tidal pump and other components will cost in the order of $100,000, and will design and scope costs for further work. Preliminary materials cost estimate for the pump model shown in the attachment is $30,000, including $10,000 for the balloon, $5000 for ropes, $10,000 for the plastic fabric components of the pump, weight and pipes, and $5000 for sand obtained locally. 

A key cost benefit is the potential to source CO2 from High Efficiency Low Emission Coal Fired Power Stations, recycling the emitted carbon for a range of valuable uses, and enabling the coal industry to invest in a method that will enable it to continue to operate without wrecking the climate. 

Potential negative side effects need to be fully analysed through a transparent scientific process. My assessment is that the environmental and economic benefits of a method to reduce the heat and acid load of the sea while also mining carbon from the air vastly outweigh any risks, but this is a claim that needs robust testing.

Time line

Year 1: Mobilise funding and regulatory partners

Year 2: Desk and Laboratory Tests

Year 3: Field Tests

Year 4: Field Deployment in coastal waters

Year 5: Extension to Deep Ocean

Year 6-10: Expansion

The Medium and Long Term aim is to use ocean industrial technology to manage the stability of atmospheric carbon.

Related proposals

References, p82

OMEGA Feasibility Study for Wastewater to Biofuels. Publication number: CEC‐500‐2013‐143.