Peak Phosphorus: Is there enough for biofuels at scale?

March 4, 2011 |

Forget water or oil, we’ll run out of phosphorus first, say some. Will that spell “doom” for biofuels as usual?

The world’s oil supply, by some calculations, will begin to run out at the end of this century – for some countries, its long gone, never there, or distress is just right around the corner. The economically affordable supply – or a justly distributed supply – or any of that – we may be well past that day now.

The destabilizing asymmetries of precious resources when they become really, really scarce — who has what, and where, and at what price; how absolutely corrupt can absolute power really make you. Those are the flavors in the awful end game that causes so much consternation in defense policy circles around the globe.

But we may not have to wait until the end of the century to have a real good model for a completely destabilizing loss of a strategic and irreplaceable resource.

Is it water? Breathable air? Nitrogen? Hydrogen? Insincerity in Washington? No, no, no, no and most definitely no.

It’s phosphorus. Environmentalists and the scientific community have been warning for the past two years that global phosphorus stocks are being depleted dangerously fast.

Philip H. Abelson wrote a few years back in Science: “The current major use of phosphate is in fertilizers. Growing crops remove it and other nutrients from the soil… Most of the world’s farms do not have or do not receive adequate amounts of phosphate. Feeding the world’s increasing population will accelerate the rate of depletion of phosphate reserves.”

Why care about phosphorus at all?

Why should you care? Well, if it doesn’t matter to you that you have six feet of sugar-phosphate coil inside each cell of your own DNA, and all living things depend on it – think of it another way. The depletion of mined sources of phosphorus places a hard stop on biofuels, and on agriculture. You can’t grow anything without it. Like biofuels…or food…or even a fingernail. It’s the P in the farmers armor of NPK, or nitrogen, phosphorus, potassium that represents the key elements of soil fertilization.

But it goes well beyond the problems of terrestrial crops. It is a hard-stop, limiting factor even in wonder crops – or especially in wonder crops, such as algae.

“I suppose you have to blame Green Fuels for all this great hype about algae,” mused Live Fuels CEO Lissa Morgethaler-Jones, who went through the dismal phosphorus outlook with me the other day. “They put this myth out there that all you need is ‘sunlight, water and CO2’. But you need 60 nutrients. The ugly truth of algae is the Redfield Ratio, developed by the oceanographer Alfred Redfield back in the 1930s, who concluded that algae seem to need carbon, nitrogen and phosphorus in a 106:16:1 ratio, and any of those is a limiting factor if you run out.”

Well, that’s dire. But then, it got worse.

“The US has about 30 years of phosphorus left, at present rates of use,” Jones added. “After that, you can’t grow food. If we ramp up biofuels according to the existing plans, you might have 20. The great thing about algae is that it grows in incredible concentrations of biomass, compared to terrestrial plant, but if you get five times the yield, you need five times the phosphorus.”

Here’s a primer on phosphate fertilizer from the USGS. Says that US proved reserves, for example, are 1.2 billion tons. Now, at 50 pounds of application per acre, that gives you 48 billion acres of fertilization. Over 10 years, looks pretty good; over, say, 6,000 years – and there will be people in 6,000 years and they’ll need it too – then you have enough to fertilize about 8 million acres a year, or just about enough crop to feed, say, the people of the New York – Boston corridor.

Well, that’s even more dire. I began to perspire slightly, then caught myself. Am I leaching phosphorus? Yikes.

Well, what about low-input crops, like switchgrass? What about woods? What about algae? Turns out everything needs phosphorus – some perform better than others at fertilizer uptake, some pull it better from the soil. So here’s one problem that really isn’t solved through higher yields – through the “pour it on” approach that has juiced US crop yields for so long.

And of course, no CEO takes you through the worst case scenario of an end to civilization as we know it, without having the solution wrapped tightly somewhere in the IP. So I collected myself, and poised my pen to get some instruction on the solutions from Morgenthaler-Jones.

Of course, then it got worse.

“Think of how it’s played out back in 2008,” Jones said. “There were those riots because of food shortages. There was rioting in 70 countries, two governments fell. Now, we have equalled the high prices of 2008, only the economy has not recovered. Something is really wrong.”

I am completely depressed. The IEA tells me we are running out of fossil fuels. Friends in the environmental community point out the depletions in the fresh water supply. Now, there’s a hard stop on US food production, starting in something like the next 10 to 30 years.

"We're doomed. We'll never make it," intoned Glum, he of Adventures of Gulliver fame

Are we doomed?

Well, not exactly. A lot of the phosphates that we used up over the years – well, not all of it is locked up in the plants we grow. A lot of it leached out, and drifted towards the rivers and the oceans. Where it turns out that theres, basically, more phosphorus than we can foresee needing in any population projection we currently have (the world population is expected to level off at around 9 billion people, not too long after mid-century).

“The salvation is farming the ocean,” Jones suggests, “where you can grow algae, and feed it to fish, and harvest all your oils, and proteins, and carbs from them.” There, nitrogen-fixing cyanobacteria, and large levels of dissolved phosphorus and potassium in seawater, give us options that range well beyond the “short-term awful” that we face on land. Algae are highly efficient little phosphorus munchers, as it happens.

That’s how some of the best phosphate concentrations appeared on land land in the first place. Algae and other phytoplankton took it from the ocean, fish ate the algae, sea-based birds ate the fish, and bird droppings formed the phosphate-rich deposits of, say, coastal Peru.

We talked awhile about algal blooms, and where these farming regimes might emerge. “First remember,” said Jones, “that basically oceans are deserts – if there was an abundance of all the nutrients you needed, there would be algal blooms everywhere, but you only find them in selected areas.”

Hang on, help is on the way

But there are other ways to extend and control the use of phosphorus, and thereby extend current stock and make biofuels less of an accelerator of phosphate depletion. One is controlling runoff, and another is making plants more responsive to phosphorus applications.

On the subject of the former, a University of Arkansas research team came up with an approach that combines land-based crops and algae. Jamie Hestekin, UA assistant professor and his research team of undergraduates form the Honors College plus some graduate students have developed a trough system for growing algae.  The troughs are fed water from creeks that are rich in both nitrogen and phosphorous, and add carbon dioxide through hollow fiber membranes.  This process removes the excess chemicals, and grows algae.    The algae is then harvested and ground to a fine powder that is treated with acid and heated.  The process produces sugars which are fermented into butyric, lactic and acetic acids.  Thanks to the work of a doctoral student, a membrane separates the three acids by using electrodeionization to quickly separate the acids.  The butyric acid is then further fermented to produce butanol.

On the latter, there is hope, too. Dean Taylor of the Iowa Corn Growers Association highlighted that Iowa farmers have reduced nitrogen fertilizer application rates per bushel have declined by 38.3 percent since 1980 and phosphorus application rates by 52.4 percent. Taylor also noted that Iowa farmers are developing a new modification to corn genes that would further reduce nitrogen needs by 20 percent.

Now that’s a clever approach, which suggests that science will greatly extend some of these problems by making agriculture far less phosphorus intense.

Insanely great symbiosis – a topic for another day

The work of Iowa farmers (and farmers everywhere) in improving yields and reducing usage is to be applauded. The Arkansas approach is, perhaps, the most interesting : re-capturing, re-using – producing food, and feed and fuels in symbiosis, in complimentary cycles where the run-off of the one is the feedstock of the other. That’s another topic for another day.

The aquafarm concept of LiveFuels is far out, and compelling. We’ll be keeping an close watch on this approach of growing algae for fish food, and then harvesting the fish.

In some ways it reminds us of what Solazyme has been preaching, ironically about algae – to avoid using organisms for what they do poorly, but focus on what they are insanely great at – in Solazyme’s case, using algae not as a means of sequestering energy from the sun, but rather as a fantastic machine for producing oils from sugars.

In LiveFuels case, they do like algae’s ability to capture nutrients, a fish’s skill in capturing algae, and our skill in capturing fish. In its own way, that’s a symbiosis.

Ok, feeling better now.

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