Harnessing the electrical power of trees

[y_p_w]

Just saw something interesting in my line of work.

I'm not talking about the happening commercially yet, but apparently
some researchers at MIT and a private company are working on
harnessing the electrical potential in trees for remote weather (i.e.
fire risk) monitoring equipment. Of course the basic problem with
using typical solar powered equipment in the forest is that such
equipment needs clearings that won't always be available in a densely
forested area. They're testing a device to tap into the electrical
potential (from pH differences) between the roots and the surrounding
soil. The trees actively regulate their pH via biological processes.
Apparently they're working with the USDA Forest Service to to field
test this. They can get one volt out of this, which may be enough to
charge the batteries and keep the equipment running so that it can
output a signal.

http://voltreepower.com/
http://www.eetimes.com/news/latest/showArticle.jhtml?articleID=210604688

Apparently most of these weather monitors are already attached to
trees. It would be interesting if I came across one of these devices.

[VtSkier]

Neat stuff certainly and from what I know
(not much really) 1 volt is certainly enough
potential, but what is the current (amps, or
more probably, milliamps)?

[y_p_w]

On Sep 30, 12:12 pm, VtSkier <VtSk...@nospam.net> wrote:
> y_p_wwrote:

> > Apparently most of these weather monitors are already attached to
> > trees.  It would be interesting if I came across one of these devices.
>
> Neat stuff certainly and from what I know
> (not much really) 1 volt is certainly enough
> potential, but what is the current (amps, or
> more probably, milliamps)?

I think it depends on the size of the tree. I would think up to
several amps. With batteries the voltage is generally dependent on
the chemistry, but with voltage dropping gradually after the battery
is depleted. Larger cells are generally more capable of outputting
higher current. I checked out some of this, and supposedly even
smaller plants can be tapped.

Any low current device should be able to tap into a "voltage source"
regardless of the max current the source can put out. If you're
powering a low-current 1.2 volt device, it doesn't really matter if it
taps a silver oxide button cell, a AAA battery, or a D cell. But if
it's recharging a battery, more than just milliamp current would be
desirable.

I don't know if it'll ever come to the point where we'll be tapping
trees to power our battery chargers in the backcountry.

[Galen Hekhuis]

On Tue, 30 Sep 2008 16:08:08 -0700 (PDT), y_p_w <y_...@hotmail.com>
wrote:

>On Sep 30, 12:12 pm, VtSkier <VtSk...@nospam.net> wrote:
>> y_p_wwrote:
>> > Apparently most of these weather monitors are already attached to
>> > trees.  It would be interesting if I came across one of these devices.
>>
>> Neat stuff certainly and from what I know
>> (not much really) 1 volt is certainly enough
>> potential, but what is the current (amps, or
>> more probably, milliamps)?
>
>I think it depends on the size of the tree. I would think up to
>several amps. With batteries the voltage is generally dependent on
>the chemistry, but with voltage dropping gradually after the battery
>is depleted. Larger cells are generally more capable of outputting
>higher current. I checked out some of this, and supposedly even
>smaller plants can be tapped.

Could you hook them up in series? A grove of trees could put out a
fair amount of power, and there are dc voltage converters and fairly
efficient inverters now.

[Stormin Mormon]

Wait till the tree huggers hear about this. They will be whining about
sapping the trees strength. Like so many generations ago, we thought that
dirty magazines sapped a boy's strength.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
.

"Galen Hekhuis" <ghek...@earthlink.net> wrote in message
news:6sc5e4p812cpctl09...@4ax.com...

[y_p_w]

On Sep 30, 4:26 pm, Galen Hekhuis <ghekh...@earthlink.net> wrote:
> On Tue, 30 Sep 2008 16:08:08 -0700 (PDT),y_p_w<y_...@hotmail.com>

> wrote:
>
>
>
> >On Sep 30, 12:12 pm, VtSkier <VtSk...@nospam.net> wrote:
> >> y_p_wwrote:
> >> > Apparently most of these weather monitors are already attached to
> >> > trees.  It would be interesting if I came across one of these devices.
>
> >> Neat stuff certainly and from what I know
> >> (not much really) 1 volt is certainly enough
> >> potential, but what is the current (amps, or
> >> more probably, milliamps)?
>
> >I think it depends on the size of the tree.  I would think up to
> >several amps.  With batteries the voltage is generally dependent on
> >the chemistry, but with voltage dropping gradually after the battery
> >is depleted.  Larger cells are generally more capable of outputting
> >higher current.  I checked out some of this, and supposedly even
> >smaller plants can be tapped.
>
> Could you hook them up in series?  A grove of trees could put out a
> fair amount of power, and there are dc voltage converters and fairly
> efficient inverters now.  

I think the basic problem with that is that the soil is electrical
ground. Hook them up in series that way and you're going to be
shorting all but one of your sources.

If you want to do that and your current needs are relatively low, I
think a charge pump can do that. Charge pumps are used in devices
like flash memory where the source is low voltage but required erase
voltages are much higher.

I'm not sure exactly what forest monitoring equipment needs. I'm
wondering if this might even be enough for something like emergency
beacons in the backcountry.