Desert farms could power flight with sunshine and seawater

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What if you could grow biofuels on land nobody wants, using just seawater and sunlight, and produce food at the same time?

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What if jet fuel could be grown sustainably? Fe Ilya/Flickr, CC BY-SA
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The Conversation

What if jet fuel could be grown sustainably? Fe Ilya/Flickr, CC BY-SA
What if jet fuel could be grown sustainably? Fe Ilya/Flickr, CC BY-SA

The aviation industry is a major source of greenhouse gas emissions. In 2011 aviation contributed around 3% of Australia’s emissions. Despite improvements in efficiency, global aviation emissions are expected to grow 70% by 2020 from 2005. While the industry is seeking new renewable fuel sources, growing biofuels takes up valuable land and water that could be otherwise used to grow food.

But what if you could grow biofuels on land nobody wants, using just seawater and sunlight, and produce food at the same time?

That’s just what a new project in Abu Dhabi is seeking to do. The Integrated Seawater Energy and Agriculture System, or ISEAS, will grow sustainable food and aviation fuel in the desert, using seawater and sunshine, in a way that is eminently transferable to similar arid regions around the world.

The project was announced in January 2015 and is now under construction.

So, how does the project solve the biggest environmental problems?

A triple dilemma

Energy, water and food problems frequently compound each other, each making the others more difficult to resolve.

Examples abound: think of wasteful irrigation coming up against water limits and threatening reductions in food production. But there are some projects that turn the issue around and bring water, energy and food issues into positive relations, each strengthening the others.

One example of this is the Sundrop Farms project in South Australia, on which I previously wrote on The Conversation, where abundant sunshine and seawater are used to produce electric power and fresh water to cultivate greenhouse crops like tomatoes.

The Sundrop Farms project is moving ahead, and has won substantial financial support from the global venture capital firm KKR in addition to its earlier support from the Clean Energy Finance Corporation, as well as a contract to supply fresh produce to supermarket chain Coles over the next ten years.

The Abu Dhabi project is even more ambitious and is called “seawater farming”. It involves the use of salt-tolerant plants like mangroves and the oil-rich Salicornia as well as aquaculture of seafood such as shrimps and fish.

Salicornia is a salt-loving plant that doesn’t mind getting wet. Cristiano Cani/Flickr, CC BY

 

The project was developed through the Sustainable Bioenergy Research Consortium in Abu Dhabi. It involves as partners the airline Etihad Airways, the Masdar Institute of Science and Technology (from the UAE), as well as corporate giants Boeing, General Electric and UOP Honeywell. These corporations provide the funding and a potentially (vast) market.

The idea is to rapidly scale up various options for securing the biomass and complementing it with associated activities to generate a closed loop operation.

How does it work?

First, seawater is used in aquaculture ponds, where (2) fish and/or shrimp varieties can be grown (= food). Then (3) the wastewater from the aquaculture, which is rich in organic nutrients, is used to irrigate a salt-tolerant crop of Salicornia.

This crop is harvested (4) and the oil extracted from the seeds (= aviation biofuel). Water is then drained from the salt-tolerant crops (5) and fed into a mangrove wetland, where it is naturally purified and carbon can be sequestered (6).

Outside this sequence there is solar energy input to drive the crop production and energy production needed for pumping.

A chart of the process is shown here:

ISEAS

 

Solving complex problems

The project solves the problem of waste disposal with fish farming (aquaculture) by channelling the organic wastes as irrigation to act as fertiliser for the cultivation of the Salicornia plants. The Salicornia plants themselves (known as halophytes, or salt-resistant species) need only the seawater and grow on arid land.

The project eliminates the problem with most biofuels that they are perceived as taking away water and arable land that could be used for food production. Instead the Abu Dhabi project produces fuel and food and recycles everything.

The current pilot farm is entirely closed-loop, with the seawater drawn originally from the ocean passing through the various stages and finally fed to mangrove plantations. The water is filtered through the mangroves, extracting the final nutrients, and the water can either be fed back to the ocean or recycled to the fish farms. All energy used (such as for pumping the water) is generated with a solar array – so there is no fossil fuel input at all.

The project is achieving remarkable success because it is backed financially by large players – Etihad itself as the principal airline, the Masdar Institute of S&T, and corporate giants like Boeing.

The project will scale up quickly. The pilot project is a plant covering 2 hectares, but in three years it is expected to grow to a 200 ha demonstration scale involving around 140 ha for the Salicornia cultivation, 30 ha for the aquaculture and 20 ha or more for the mangrove plantation.

Could Australia do the same?

Australia is a country with vast arid areas, copious quantities of seawater and sunshine – all the ingredients needed for a similar solar biofuel and food project.

It has a national air carrier in Qantas that has already experimented with various kinds of aviation biofuels. It has a national R&D organization in CSIRO that could organize such a project.

Australia has long experience in development of agricultural models that can cope with high salinity levels. There is a strong research tradition cultivated in West Australia with the CRC for Plant-based Management of Dryland Salinity and its successor the Future Farm Industries CRC – which had to close its doors in mid-2014 for lack of continued support.

Such a project would produce food, both for domestic consumption and export; it would produce aviation biofuel and help restore a fuel processing value chain and again a domestic as well as an export product; and it would utilise water in a way that can promote a means of halting desertification and restoring fertility in arid areas. It is a big idea for a big country.

The Conversation

Source: The Conversation. Reproduced with permission.

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13 Comments
  1. Jacob 4 years ago

    What would be the cost per kilolitre of jet fuel from such a farm.

    • Vic 4 years ago

      I guess it would depend on the price of fresh prawns in Abu Dhabi.

      • Jacob 4 years ago

        There is only 1 prawn farm in UAE.

    • bill 4 years ago

      I’m always amazed by questions like this. Its a pilot project! If it shows promise, in 3 years, it will scale up to a demonstration project. The whole point is to investigate potential answers to hundreds of questions, including that one.

      • Jacob 4 years ago

        Professor Sadoway said “you have to think about the price point from day 1”. “You cannot make something out of a rare element like Platinum and think you are going to scale it up”.

        Some idiots thought that solar panels on roads are a good idea.

        How about putting solar panels on houses instead.

        • wideEyedPupil 4 years ago

          solar freakin scammers!

  2. Miles Harding 4 years ago

    The true cost of aviation will be revealed…

    My first thought was that this is loopy, but a quick bit of research put some numbers to it.
    My calc indicates 4.5L/yr/m^2, Wikipedia puts this at 5-13 l/m^2/yr, so lets use 5.
    200Ha would yield about 10M litres.

    An average domestic jet flight uses about 2.5L/100km/seat, so a 3000km flight for a 150 seat aircraft would burn about 11,000L. The 200Ha farm could produce enough fuel for about 900 of these flights per year. Good, but that aircraft probably does over 1000 per year now, so this would only satisfy a single airliner.

    The world has 7000 aircraft in just the top 10 airlines. probably more like 20,000 in total. Based on this, some 4 Million Ha would be needed. This amounts to about 40,000 square km, or 10M acres! The USA irrigates about 50M acres in total.

    Perhaps we will fly a lot less in the future!

    • JonathanMaddox 4 years ago

      A fair point, but this is hardly the only way to produce carbon-neutral fuel for aircraft.

    • Jacob 4 years ago

      3000km flight?

      MEL to SYD is well under 1000km.

      This farm in UAE supposedly uses salt water.

      But there has to be a price point in mind, ie, how many $ per kilolitre are they aiming for.

      • Miles Harding 4 years ago

        The 200Ha farm could probably only still supply a single airliner doing the SYD-MEL run, it will make more flights per day and consume more per passenger km due the on-ground run time and climb losses which are partially offset by the descent glides.

        As for the price, wisely not mentioned. A 2 square km tank farm isn’t going to be cheap to operate and then there’s the refining costs to get a safe and usable fuel. Jet fuel is much more difficult to make than bio-diesel, as it has a more demanding specification. The list of critical properties I’ve seen fills a page. There were a surprising number to accommodate engines of various ages and service conditions.

        It may be that this is not so much a replacement as an extender to be blended with existing fuels.

        • Jacob 4 years ago

          I got the price now, U$1.30/US Gallon. So about U$0.35/L for jet fuel.

          There is a firm in USA called Algenol.

          • Miles Harding 4 years ago

            That’s pretty cool!

            The video indicates 9000 gallons of ethanol per acre per year; or 85KL/Ha/year in a language we understand. The fraction of jet fuel is only about 400gal/acre/year, or 3800L/Ha/Yr.

            Ethanol isn’t as efficient as jet fuel, so lets assume a little over 1/2 for this scaling exercise. 85KL over 200Ha is 17ML/Yr, divide by almost 2 and we arrive at about 10ML/Yr.
            It makes sense for this to be similar.

            A strip of coastline 10,000km long x 4km wide will be needed for BAU jet fuel.

            We currently get through about 90M barrels of oil per day, or 4,000GL/year, so my estimated 200GL/Yr of jet fuel would be about 5% of the total. Hmm, surprisingly reasonable in this check.

            According to the US DOE, Jet fuel makes up about 8% of US oil use, so 12.5 times as much would be needed to continue business as usual across the oil spectrum. This would amount to that strip widening to 50km. I suspect that there is not 10,000 km of suitable coastline in the world, nor is it clear that there are sufficient resources to even build even a fraction of this scale of structure.

            This puts the ancient, stored, energy we are pumping out of the ground these days into perspective. Whatever happens, it is certain that business as usual will not survive the end of the oil age.

          • Jacob 4 years ago

            Not sure what firm you are talking about with your figures above.

            But the American firm that I mentioned grows algae in plastic tubes as seen in the video.

            A lot of cars will be replaced by electric cars, but electric aircraft are not on the horizon.

            So that is why I am thinking of jet fuel.

            Algenol produces fresh water as a byproduct, so that is amazing and I suppose could be used to wash the plastic tubes in dusty parts of the world!

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