Tilapia farming in the desert

Every now and then a report gets published that makes me annoyed. Boeing reveals “the biggest breakthrough in biofuels ever”, published by Energy Post last week, and evidently read by >95,000 people in a single day was one them.

Oil companies watch out. Biofuels are on the verge of a breakthrough that will transform the oil market. Not only that: it will also green the planet.

Morgan is not some green dreamer. He is Director of Sustainable Aviation Fuels and Environmental Strategy at The Boeing Company in Seattle in the US. He has worked on Boeing’s biofuels program for 10 years. And he is convinced that researchers at the Masdar Institute, sponsored by Boeing, Honeywell’s UOP and Etihad Airways, have achieved a breakthrough in biofuels that will make it possible for countries all over the world to turn their deserts into biofuel-producing agricultural lands.

The consortium then decided to set up a pilot production facility which is now being built in Abu Dhabi right next door to Masdar City. There is yet one more element to this to complete the story, because what the researchers decided to do in this pilot project is also unique: they decided to combine the production of biofuels from halophytes with aquaculture.

I’m afraid that whenever I read about Green strategies designed solely to reduce CO2 emissions that otherwise show little regard for the natural environment and delicate ecosystems, my hackles rise. Karel Beckman, the author of the Energy Post piece provided a link to a Power Point authored by Professor Robert Baldwin which shows some potentially interesting engineering and science behind the incredible claims. And so let me begin with a critical look at what this is all about. At the end I pose a number of fundamental questions, the answers to which are required for any evaluation of this “breakthrough” to be made and I’m hopeful that Professor Baldwin may respond.

The integrated seawater agriculture system (ISAS)

At the heart of this “breakthrough” lies a plant called Salicornia that grows in deserts and is tolerant of salt water and has potential as a bio fuel. A major problem with temperate latitude biofuels is their use of agricultural land and fresh water (and also pesticides and ammonia based fertilizer made from natural gas) and so it is proposed to over come these problems by growing biofuels in the desert irrigated with salt water – too good to be true? And all this is to be done in a Green sustainable way.

The second part of the story is to have aquaculture tanks rearing fish (Tilapia) and shrimps at the front end, all the faecal waste from this operation to be pumped to the Salicornia beds where the faeces provide nutrients.

The system diagram (Figure 1) indeed shows some serious thought has been put into this scheme. So what could possibly go wrong?

Figure 1 Process diagram and flow for the ISAS system. This may be broken down into 3 main components: aquaculture to the left, Salicornia and mangrove farming in the centre, fuel refining and processing to right.

Energy Return on Energy Invested (ERoEI)

In the energy world there are two forms of energy extraction. The first, and by far the most important is primary energy extraction, for example oil and gas and hydro electric power. These provide the energy surpluses that run society. The second is energy conversion where one type of energy source is converted into another. The best example of this is electricity production from coal, gas and nuclear where the thermal energy from these sources is converted to electricity. Surprisingly, temperate latitude bio-fuels are also an energy conversion where natural gas is converted to fertilizer and then to corn and then ethanol. There is virtually zero energy gain and the process is enabled by mandates and Americans placing a higher value on liquid fuel than natural gas.

In the ISAS system I count 16 energy inputs

  1. Electricity to pump water into fish ponds
  2. Electricity used in shrimp hatchery and feed production
  3. Electricity used in Tilapia hatchery and feed production
  4. Electricity used in shrimp farming and processing
  5. Electricity used in Tilapia farming and processing
  6. Electricity used to pump water and ecscrament to the Salicornia fields
  7. Additional fertilizer production and transport
  8. Diesel used during planting
  9. Diesel used during harvesting
  10. Transportation of harvest to Biomass facility
  11. Pumping “treated seawater” back to the ocean
  12. Electricity used in biomass facility
  13. Energy used in the Oil processing facility
  14. H2 production (from what?) and transport to Oil Processing Facility
  15. Transport of “renewable” jet fuel to market
  16. Energy used to construct fish ponds, hatchery, irrigation system, biomass facility, oil process facility etc.

While electricity could conceivably be made from solar or nuclear power in the UAE, the most likely source right now will be crude oil or natural gas. At the outset I would therefore voice concern that this may be an extremely elaborate and expensive way of converting fossil fuel into a bio-jet-fuel. Temperate latitude bio fuels tend to have ERoEI ~ 1 while tropical sugar cane ethanol has ERoEI ~ 6. If one is willing to set aside the use of rainforest to grow liquid fuel, then the latter is worth while, the former is not. The first hurdle that the ISAS system needs to clear, therefore, is demonstration of a large, positive net energy (net energy = ERoEI-1). If ISAS is net energy negative then the outcome would result in turning more fossil fuel into less bio-jet-fuel and harming the desert environment en route.

The salination of soils

Figure 2 shows the cultivation set up with irrigation pipes and Salicornia plants growing  in the desert sand. Here I have to presume that the irrigation pipes seep water to the plants either continuously or periodically. And this is salt water that is being applied, and when it evaporates leaves behind a salt residue that will build up over time eventually destroying the soil. Prof. Baldwin’s presentation does flag “salt management” as an issue.

Figure 2 Salicornia growing in desert soil alongside salt water irrigation pipes. The water applied evaporates leaving behind a salt residue that will inevitably accumulate in and eventually destroy the soil.

Figure 3 taken to an extreme, too much salt will develop a salt pan, one of the most arid and hostile desert environments on earth.

Taken to an extreme, adding too much salt water to a desert soil will form a salt pan, creating a totally arid and sterile environment. How does the Masdar consortium propose to mitigate this problem?

Salinity control and fresh water supply

Average seawater has a salinity of 35 g / l, i.e. 35 parts per thousand (ppt). The experimental results from the Masdar Institute team shows optimum productivity of Salicornia at salinities of 20 ppt suggesting that to optimise the system, large amounts of fresh water are required to dilute seawater. Freshwater seems also to be required for germination of the plants (Figure 4). In the world’s deserts, where is this freshwater to come from? Furthermore, since it is to be reasonably anticipated that the soils are to become enriched in salt over time, how will this impact productivity and be mitigated?

Figure 4 Productivity is closely linked to salinity of irrigation water. It is interesting to note that Salicornia seems to thrive on salt water with optimum productivity at 20 parts per thousand. However, salt will quickly accumulate in the soil producing high salinities even when lower salinity water is applied. 

Salt water supply

The leading article gives the impression that the worlds deserts can be transformed into industrial scale bio fuel agricultural systems when in fact, the need for salt water seems to limit this developmental concept to coastal regions given the high energy and financial cost of building corrosion resistant pipelines and pumping water.


One of the most important questions to ask is on yields. How much desert has to be used to produce a barrel of Green jet fuel?

This question is perhaps best reduced to “How many acres of desert are required to produce sufficient jet fuel for a single flight from Abu Dhabi to New York?” Ultimately, we need to ask the question, what will a barrel of bio-jet-fuel cost?

Environmental impact

Assessing environmental impact gets to the heart of the matter. The world’s deserts are delicate and important ecosystems. This proposal will likely destroy this environment where the technology is deployed. And so we need to know how many acres of coastal desert need to be given over to Salicornia production to make a significant impact on global jet fuel consumption. This links to the yield question above.

And one final point, evaporating seawater in the desert will cause a very powerful greenhouse warming that may disrupt local weather systems. Not to mention the change in albedo. Are these factors taken into account in this pursuit of mitigating climate change?

Questions for Professor Baldwin

And so to my questions for Professor Baldwin, the author of the presentation at the heart of this critique.

  1. What is the ERoEI of the ISAS system? This may be reasonably adjusted for the fish production output benefit, but should also account for thermal losses in power generation plant, or for fossil fuel inputs to the manufacture of solar panels etc.
  2. How will desert soils cope with irrigation by salt water? How will this be mitigated?
  3. Where does the fresh water supply for the system come from?
  4. Is this process restricted to coastal deserts where there is a salt water supply?
  5. How many hectares of desert are required to provide  bio-jet-fuel production to fuel a single Boeing Dreamliner (or equivalent) trip from Abu Dhabi to New York?
  6. How is converting pristine desert to industrial scale bio-jet-fuel production Green, sustainable and of benefit to global society?
  7. What are the estimated local climatic impacts of evaporating large amounts of water over dry desert?

Concluding points

I have absolutely no objection to the  financially and energy wealthy UAE experimenting with desert bio-jet-fuel production systems as described in ISAS. It is sometimes the case that allowing individuals to think out of the box like this, unconstrained by finance or energy (laws of thermodynamics) that some significant scientific breakthroughs may be made. What I object to is embroyonic research being presented by Energy Post as the biggest break thorough for bio-fuels ever, in an environmentally sustainable way, when none of the data to support these spectacular claims are offered.

Figure 5 The Greening of desert Masdar style. The picture I believe shows algae cultivation.  The UAE may well wish to plan for the day when their oil production begins to decline and using their deserts for energy production may be justifiable to meet that end. Arguing that habitat destruction is somehow Green and sustainable, is not.

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11 Responses to Tilapia farming in the desert

  1. Nigel Wakefield says:

    I came up with pretty much a carbon copy of this scheme about five years ago.

    The major difference was the area of land I identified as perfect was a ~200,000 hectare piece of land called the Aftout es Saheli in Mauritania. This land is separated from the Atlantic Ocean by a strip of dunes and lies, essentially, at sea level; as such the soil is already deeply contaminated by salt. It runs from just south of the capital Nouakchott pretty much all the way to the border with Senegal. Coastal erosion is a major problem; the idea was to create a mangrove forest on the land side of the dunes to help bind the soil and prevent further erosion.

    The main purpose of the idea was to create some vital export income (tiger prawns, tilapia, mangrove honey) for a very poor country. Bio-oil products were to be used to replace, to an extent, the country’s reliance on fossil fuel imports and to power the tractors, etc required for the scheme. Mangrove leaves were to be used as fodder for camels (halophyte tolerant); 60% of milk consumed in Mauritania comes from camels. Mangrove wood was to be pyrolised into charcoal to go some way to replacing kerosene as a cooking fuel. All electricity was to be provided by wind and solar.

    I thought it was a very cool idea… seems like cleverer, more connected, people than me have decided to make it a reality, albeit in a far wealthier country and without the benefit of using land already contaminated by salt.

  2. Steve Fawkes says:

    As Richard Feynman said;
    “For a successful technology, reality must take precedence over public relations, for nature cannot be fooled.”
    There is too much PR and not enough reality in most “alternatives” like these.

  3. Roger Andrews says:

    In the 1980s and 1990s I had a beach house at Puerto Peñasco in northern Mexico that was located only a short distance from a University of Arizona experimental plot where they were growing halophytes. Here’s one of the papers that came out of this work:


    According to the paper:

    * Salicornia Bigelovii yields 15-20 dry tonnes/hectare annually.

    * A dry tonne of Salicornia Bigelovii contains the heat equivalent of a tonne of lignite

    * Production costs were estimated at $44-53/dry tonne in 1987 (about $80-95 in today’s dollars).

    I don’t think we can use these numbers to estimate what a barrel of jet biofuel is going to cost and how many hectares of Salicornia will be needed to produce it, but with a cost/btu four or five times that of lignite Salicornia doesn’t look too attractive even before you start adding Tilapia poop.

  4. Alfred says:

    Around 1975, I went with my Dad to Abu Dhabi and Dubai. We met some of their planners and they wanted to know what suggestions we had for helping them find something for “after oil”. My Dad – wrongly it would seem – suggested that they used their geography to make salt evaporation ponds and to export the salt. They did not like it at all. 🙂

    At that time, we had no idea that some of the largest airlines would be based in these places or use them for transit – as a way of adding value to the oil.

    Personally, I think that in principle concepts like this one ought to be tried first.


  5. Max Beran says:

    Second sentence of opening para doesn’t make sense.

  6. William Mackin says:

    The technology is real. The results are good. I have seen it. I am glad they have made progress. The site produces lots of food in addition to fuel. In fact, the fuel is the least valuable part of it and it seems ridiculous to turn nice vegetable oil into jet fuel. The fallacy of your EROEI calculations is that they assume that technologies are stagnant. Yes – corn ethanol has bad EROEI numbers if you use 1970’s technology. If you allow for improvements, then you can double or triple the EROEI and make these techniques much better. Much the same can be said for saltwater agriculture. It produces so many beneficial products – food, fodder, fuel, and fresh water – that it is a huge opportunity for sustainable development.

    Three points: There are millions of ha of degraded salinated land around the desert zones of the world. Seawater agriculture rejuvenates that land by filling depleted aquifers with saltwater. Thus, we are not losing functional desert. The technique repairs disrupted desert habitat. Secondly, the systems create a freshwater lens that hits the surface and provides water for other crops. Third, because the systems take seawater and allow it to move into depleted aquifers on land, they actually lower sea level. If you applied this system on a massive scale in the world’s depleted deserts, you could deal with the most expensive part of climate change.

    Read the paper and look at globalseawater.
    I have been wondering since 2008 when I first witnessed this why we were not employing this technique much more aggressively. http://seawaterfoundation.org/gsi/index.html

    I have no financial interest in this company or this technique, but sometimes I wish I did.

    • Roger Andrews says:

      Euan will correct me if I’m wrong, but I don’t think he was saying that we should forget about halophytes altogether. His point was that Morgan’s claim that Boeing had made the “biggest breakthrough in biofuels ever” was, to put it charitably, overblown.

      There’s also nothing new about the technology. There are a number of existing pilot plants and experimental stations where the potential for producing biofuels from halophytes is being studied. One of them is a NASA facility which grows salicornia and fertilizes it with – guess what? – fish waste:


      According to this article halophyte biofuels are a long way from commercial reality. Using halophytes as food indeed seems to make more sense. After all, humans have been eating them for thousands of years.

    • Euan Mearns says:

      The site produces lots of food in addition to fuel. In fact, the fuel is the least valuable part of it and it seems ridiculous to turn nice vegetable oil into jet fuel.

      Food is very special to us when it comes to energy investment and return and it is the case in the ISAS system that food production complicates the jet fuel part of the algorithm. I agree entirely that it is bonkers to use this process to make jet fuel unless it has a high proven ERoEI.

      The fallacy of your EROEI calculations is that they assume that technologies are stagnant. Yes – corn ethanol has bad EROEI numbers if you use 1970′s technology.

      Large scale corn ethanol production only came into being about a decade ago and all the papers I have read on this subject are from the last several years – so I don’t understand your claims.

      Much the same can be said for saltwater agriculture. It produces so many beneficial products – food, fodder, fuel, and fresh water – that it is a huge opportunity for sustainable development.

      Can you please explain how sprinkling salt water on the desert makes fresh water.

      Seawater agriculture rejuvenates that land by filling depleted aquifers with saltwater.

      I think it should be a MAJOR concern that valuable fresh water aquifers in the desert regions become polluted with salt.

      Secondly, the systems create a freshwater lens that hits the surface and provides water for other crops.

      I’m sorry, I cannot be bothered going on responding….

  7. Nate Hagens says:

    Great post Euan. Of all the first principles relevant to understanding humanities predicament, net energy is one of the main two**. And is completely disregarded by both the media and the scientists in the field (who both focus on dollar inputs instead of energy inputs).

    ** The other is human belief systems/self-deception/cognitive bias and the misplaced certainty with which we view our own opinions. (Almost) all of us.

    • Euan Mearns says:

      Hi Nate, good to have you call by. I agree that a lack of appreciation of the importance of net energy throughout much of society is a cause for concern. There is also a general lack of understanding of cyclic energy demand patterns that are easily met by energy stores and much more difficult to meet from energy flows.

      The net energy story is more complex than I initially understood it. You may recall some interminable discussion about ERoEI of corn ethanol. It helped me understand this controversy when I realised this is an energy conversion, actually more efficient than making electricity from gas or coal. Its made possible by mandates, land and folks preferring to but liquid fuel in their cars – thus leaving room for golf clubs in the trunk.

      The UAE are building 4 nukes. Thus they will one day soon stop burning oil and gas for electricity – freeing this up for export and the jet fuel markets 😉 Sticking a nuke on the front end of the ISES system actually changes the whole model if it were possible to make food and some liquid fuel using the surplus nuclear electricity. But I still don’t see how they get around the salt problem – the only way to get rid of that I believe is to wash it out with fresh water.

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