[permaculture] biofuels

Harmon Seaver hseaver at gmail.com
Tue Mar 18 21:20:20 EDT 2008

Brooks Miller wrote:
> harmon - you mentioned cattails for biofuel use a few times.  (typha?)

> for diesel, is it simply the oil extracted from the pressed seed head that
> is used? 

    No, it is making ethanol and running the diesels on a
ethanol/biodiesel mix. An unmodified diesel can run 80% ethanol/ 20%
biodiesel. Slightly modified diesels -- usually just adding an extra
head gasket to lower the compression ration to 18:1 or less allows you
to use almost pure ethanol with just 1%-2% biodiesel to provide the
lubrication for the injection pump and help with ignition. Further
modification can turn a diesel into a super efficient ethanol engine --
such as adding a distributor and replacing the glowplugs with sparkplugs
and replacing the injectors and pump with propane injectors, then
heating the ethanol so it vaporizes.
    Ethanol is very high octane fuel, so it needs a compression ratio of
at least 14:1 to burn efficiently. 16:1 is much better.

> have you done this?  what kind of equipment is needed to harvest
> cattails?  i'm interested.  all the cattails i've seen grow in very wet
> conditions, which would negate any kind of tractor harvesting (i would
> think).

     You probably want to grow them in paddies like rice and drawn down
the water before harvest. But harvesting by in deeper water is possible,
think of the weed cutting barges they use on lakes to get rid of seaweed.

  has anyone any information on what kind of volume per acre cattails
> yield in oil?

   No, but harvesting the tops or roots gives you about 28 dry tons per
acre at 40% starch with no fertilizer (this in Minnesota with only one
cutting per year), people have gotten 70 tons per acre and 70% starch
with fertilizer and warmer climates. The figures in "Alcohol Can Be A
Gas" give 1500 gallons per year with no inputs, and 2500 gallons a year

> also, you referred to using the roots i think for ethanol production.  i've
> heard the roots are starchy and sometimes tasty but never eaten them.  the
> same questions from above could be applied to the roots.

    You can harvest either the roots or -- much easier -- the bottom 3'
of the stalk. About the same starch ratio in either. And then the rest
of the stalk, the top part can be run through a digester, or dried and
burned for fuel to heat the still.

> do you currently have typha in production, and if so what do you use it
> for/what kind of equipment do you have.

   I've been too busy working on a new cabin to replace ours that was
burned by a trespasser, but I'm planning on building some paddies ASAP.
I have a number of springs that I can divert to flood them, also a good
year-around creek. I've got a JD 440 crawler with a loader to dig with.
   If you want to harvest the roots, the research group at the Univ. of
MN that worked on cattails to ethanol back in the 70's used a modified
potato digger to harvest. Now that I know the lower stalks are just as
good, that looks like the way to go.

> does anyone here press their own seeds for oil or know anyone with a
> farmstead oil press?

    I don't know of anyone with one, but I see quite a few Chinese oil
presses for sale these days, even on ebay. The problem with veggie oil
versus ethanol is vastly less yield per acre. I don't know where you
live, but in most of the US, the best crop for oil is rapeseed, and that
only gets you about 128 gallons per acre. And you need a combine to
harvest it. You could grow sunflowers for about 100 gallons per acre and
hand harvest it.


    Compare that to ethanol -- cattails at 1500 gallons per acre, and
their are lots of other crops that will give you 750-900 gallons an acre.
    That's a big difference. Plus, the spent mash from ethanol is very
high quality livestock feed, fish feed, chicken feed, or mushroom
substrate. Think how many pigs you can feed from the twentyfive or so
tons of high protein spent mash you get from an acre of cattails. 8-)
    Sure, you get oil cake from pressing the oil seed which is great
animal feed too -- or at least is with rapeseed or sunflowers, some of
the oilseed like jatropha or castor beans is pretty toxic. But the oil
cake yield is much less per acre too.
    Don't get me wrong, I'm a long time diesel fan, have owned a few of
them, and still feed a VW diesel, an IHC 466 turbo diesel, a '82 Nissan,
and a little 600cc diesel genset, but I'm going to be converting them
all to run ethanol. They'll last a lot longer that way too -- any engine
will last much longer, up to 3 times as long, on ethanol -- it burns
very, very clean and much cooler.
    I'm running E85 right now in my totally unmodified '91 Toyota
pickup, runs great. I'm planning on adding a custom computer
(http://www.megamanual.com/index.html) to it, along with a turbo to
raise the effective compression ratio to get more power and efficiency,
but it runs pretty well right now, and E85 is only $2.35 a gallon here.

Harmon Seaver

More information about the permaculture mailing list