An Unlikely Renewable Bottleneck: Machines to Harvest Weeds

March 16th, 2011 by Susan Kraemer

We are at a point in history when innovations are needed rivaling those of the information technology industry in speed of change – for the development of farm machinery for growing and harvesting new crops that produce energy.

Machinery suitable for growing and harvesting traditional crops have been developed, and refined, and ultimately, mechanized, over centuries. Now we have to find a way to grow biofuels, on land that’s not needed to grow food, and in a way that is economical, and massively replicable.

Currently only a handful of companies are working on the novel problem, among them, according to Craig Patterson, Manager of Commercial Operations there, Repreve Renewables.

Here’s an example of an issue they are trying to solve. Miscanthus holds great promise as a non-food, non-valuable-land biofuel, as it is a virtually a weed in the Midwest and Southeast, and can produce up to 20 tons an acre, far more than switchgrass.

The problem with it is that it can be hard to establish on a commercial basis. Although it is a weed that sews its own expansion, it does it haphazardly.

If you want to “farm” it in a way that lends itself to efficient energy crop production, you need to reproduce it from actual pieces of the underground plant system (from cuttings called rhizomes) that must be dug up and replanted, at the rate of around 5,000 rhizomes to the acre.

The speed and cost of planting, it turns out, is a real bottleneck in viability of this crop as a successful feedstock. Current planting technology can plant, at best, 20 acres per day.

A typical biorefinery needs at least 3,000 acres of crop to run efficiently, he says, but that 3,000 acres would take 150 days to plant, this way. By the time planting was done, the planting season would be long over.

“Putting five pieces of equipment on site reduces the planting to 30 days,” says Patterson.”But imagine that the planting is going on in five different states, on 15 different farms. Suddenly you need 75 teams planting all at once, across several states. In this scenario, 45,000 acres – a drop in the bucket of what is required – would require millions of dollars of equipment and labor to achieve. And that is a bottleneck”.

That’s where inventive farm machinery comes in. Repreve Renewables is one of just a handfull of companies developing machinery for the task.

Strange times. After 10,000 years of agriculture, with generations of inventors devising ways to battle weeds, in the 21st century we need to invent machinery to do a more efficient job of harvesting them.

Image: Newswise
Susan Kraemer@Twitter

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Tags: Agriculture, Miscanthus, renewable fuel

About the Author

Susan Kraemer writes at CleanTechnica, CSP-Today, PV-Insider , SmartGridUpdate, and GreenProphet. She has also been published at Ecoseed, NRDC OnEarth, MatterNetwork, Celsius, EnergyNow, and Scientific American. As a former serial entrepreneur in product design, Susan brings an innovator's perspective on inventing a carbon-constrained civilization: If necessity is the mother of invention, solving climate change is the mother of all necessities! As a lover of history and sci-fi, she enjoys chronicling the strange future we are creating in these interesting times. Follow Susan on Twitter @dotcommodity.

Anonymous

Canada grows hemp legally now, and the same problems are bound to ‘crop’ up! With America gently awakening to the new realities, and on the job again solutions are bound to flow!
Ormond Otvos

You can count on Americans for this kind of innovation. Some farm boy will come up with a biodiesel turbocharged carbide-tipped analog of a potato planter, complete with GPS steering and 24 hour a day robotic operation.

I could design one in about ten minutes.
- http://cleantechnica.com/author/susan Susan Kraemer
  
  Hi Ormond – didn’t know you designed farm machinery
MD

I’ve always argued that this is what should be done with CRP land, instead of .GOV paying someone to do nothing with the land, the land should be tree or seed bombed.
Bucketofsquid

The key is to move beyond traditional farming thought patterns. Instead of entire fields dedicated to this stuff, it could be grown on the periphery of fields growing other crops (carefully to prevent field contamination by unwanted spread) and in areas that are generally grazing land. This would give a dual benefit for grazing areas because it can feed the cattle and what isn’t grazed can be harvested for fuel production.

One concern I have is that high energy plants tend to deplete the soil so maybe this has a 7 year lifespan to allow the soil to recover. Maybe a multi-field crop rotation? By starting with 1 set of growing areas and adding more each year you can create a situation where the machinery is used each year. There is also the professional planter/harvester model where someone owns the machine and rents out their services as needed to those that don’t own the machines.
Josh

Bomb it! : http://www.wellhome.com/blog/wp-content/uploads/2011/02/Tree_Bombing_Final1.png
- http://cleantechnica.com/author/susan Susan Kraemer
  
  Wow, that is a serious concept? I had never heard of that. Very ingenious. The fact that Lockheed Martin is involved makes it a real swords to plowshares story, doesn’t it! Must check that out.
sola

Don’t forget that Miscanthus doesn’t need to be re-planted every year.

If you plant Miscanthus x Giganteus one year, it will produce biomass for at least another 7-10 years.

Even if it seems slow to plant them, it is a one-time only work for a long production period.

However, I agree, that specialized machinery would be nice for the ultra-quick deployment of Miscanthus because that would lower the cost of this promising biomass source.
- http://cleantechnica.com/author/susan Susan Kraemer
  
  That is a good point. Once the machinery is there to plant it, it can reproduce. (Maybe that is one economic factor slowing the machinery development? That it is a hefty investment for a once in 7 years need?)
  - http://www.kilogen.ie Bill Madigan
    
    Our company has been growing Miscanthus in Ireland for years and we have developed a range of machinery to harvest ,process and plant Miscanthus. We can produce all the machines you want and all the boilers you need to burn Miscanthus from 25 kw to 4000kw. The key to Miscanthus is quality rhizomes and precission planting.
    - http://www.kilogen.ie Bill Madigan
      
      Its not the rhyzome production or the planting that is causing the bottleneck it is the availability of land. If you know where there is a few thousand acres needing to be planted just let me know. Bill.
      - http://cleantechnica.com/author/susan Susan Kraemer
        
        Are you in Ireland? There is a lot less land there than here.
    - http://cleantechnica.com/author/susan Susan Kraemer
      
      Looks like your company is ahead of us Yanks. Bring your machinery out here for a trade show. We have a ton o land!