Power Plant Fueled By Nut Shells

sbszine writes "The Sydney Morning Herald is running an article about a green power plant that runs on the discarded shells of macadamia nuts. The power plant, located in Gympie, Queensland, is expected to reduce greenhouse gas emissions by around 9500 tonnes in its first year of operation."

Comments

Some times you feel like a nut...

[Powercntrl]

...sometimes a volt.

Reduction in Co2?

[zefod]

My guess is that they would burn the shells of these nuts, right? This produces carbondioxide, so how does this reduce CO2?

Re:Reduction in Co2?

[gl4ss]

those same nuts needed the co2 when growing.

so there's no 'extra' co2 introduced from millions of years back like when you burn oil/coal.

so it does reduce the total amount of co2 coming to the atmosphere, provided that somebody plants some more of those nuts(and doesn't chop some rainforest/something else that binds huge amounts of it to plant those nuts for few seasons and then chop more of rainforest).

Re:Reduction in Co2?

[zmooc]

Wrong. The only thing that matters in this context, is the percentage of CO2 in the atmosphere. While in the long term, burning plants would indeed not introduce any new CO2 into the biosystem. The only problem is that it is generally assumed it takes about 100 years for nature to create a balance between CO2-production ans CO2-consumption by plants. Just compare it to a closed system in a box with a plant and a device burning it's seeds; the plant will consume the CO2 a lot slower than the device can produce it so the CO2-level in the box will definately go up just like a sink will fill when the tap runs faster than the drain can put up with.

But in the long term it's always better to burn plants instead of oil since burning oil introduces new C into our biosystem while burning plants only raises the C-level in the atmosphere but not in the biosystem.

By the way, this only works if you assume each burned plant will be replaced by a equivalent plant. Burning more plants means the average age and therefore size of plants will decrease and therefore the amount of C these plants can hold will also decrease. And then even the space that's available for plants is declining.

Re:Reduction in Co2?

[misterpies]

Wrong wrong wrong. A nut grows in a single season. The carbon in the nut can only come from CO2 in the atmosphere. Therefore burning nuts is carbon neutral over a single nut-growing season.

Similarly, I fail to follow your example of a plant in a box. OK, while the seeds are actually aflame CO2 will be produced faster than it's being absorbed. But overall, the amount of carbon in the system is constant: anything which is not in the plant is in the atmosphere. Therefore so long as you burn the plant no more quickly than it grows, you'll never end up with a higher CO2 concentration than when you started.

Your argument only applies if you start burning something which has been growing for decades -- eg old-growth forest -- in which case you're releasing CO2 that took decades to remove from the atmosphere. But so long as you burn material grown only over, say, the last year -- eg fast-growing bamboo -- then the net amount of CO2 released into the atmosphere over that year must be zero.

Re:Reduction in Co2?

[famebait]

Just compare it to a closed system in a box with a plant and a device burning it's seeds; the plant will consume the CO2 a lot slower than the device can produce it

What makes you believe that? Are you assuming that the plant produces seeds at a diminishing rate, or that burning a seed releases more carbon than was put into building it? Because something doesn't add up here.

You are describing a closed system with a net production of carbon. If you have one of those you could be very rich indeed.

Just like a sink will fill when the tap runs faster than the drain can put up with.

That's not a closed system.

The only problem is that it is generally assumed it takes about 100 years for nature to create a balance between CO2-production ans CO2-consumption by plants.

That's a little out of context. Yes, if you completely cut down a forest, it takes a long time until there is once again the same amount of biomass contained on that area. But we're not _removing_ the ecosystem and waiting for it to return here, we're burning a nutshell in stead of allowing it to rot. The tree is still there, and it doesn't take a 100 years to replace a nutshell. If you burn a billion shells a year and produce a billion too, you have a net emission of zero. You're basically just extracting solar energy, the shells and the carbon are just carriers in the process.

There would be an minor initial 'cost' in that you're shortening the cycle a little, releasing the carbon more shortly after it's trapped compared to natural decomposition. So you get an initial emission over the first year or two after start up, as the 'cache' of decomposing shells releases its carbon at the same time as new shells are burnt immediately. But after they're gone you'll be running in balance. Or you could avoid that too by imitating nature and storing the shells a couple of years before burning them.

Re:Reduction in Co2?

[shokk]

Bullshit. Plants absorb quite a bit of carbon from the ground. That's a lot of old carbon that's released there. They estimate about 30% of the plant is old carbon.

http://www.sciencenet.org.uk/database/earth/natura lenvironment/e00077d.html

Re:Reduction in Co2?

[gl4ss]

so what you're saying is that we should kill all the plants, stop them from growing, dying? or use fossil fuels instead of something available?

yeah. that's the ticket.

from your link:
" The most important points to draw out from this briefing are as follows:

* Fossil fuel consumption is the greatest source of greenhouse gas emissions.
* Deforestation in the tropics is the second most important source of greenhouse gas emissions.
* Forests are net absorbers of CO2 while they are growing (which is stored as carbon) but then release the accumulated carbon when they die.
* Young forests absorb more CO2 than old forests, but old forests have much greater stores of carbon.It is widely recognised that old forests are valuable storehouses of carbon and should be protected.
* Logging old-growth forests and replacing them with plantations intended for timber/paper production results in a net loss of carbon which is released into the atmosphere. This is especially relevant in Canada, Russia and the Baltic States where this is most widespread, and also in Scandinavia. "

however the whole text was fairly anti-paper industry disquised as something scientific and relevant(there's barely any logging of _old_ forests in finland anyways, and the total yearly growth is _more_ than what we cut down yearly).

sure the russians do log real old forests.. but they do lots of other stuff too(bad for the environment) that is seriously in need of more attention.

i've planted ~500+ trees myself(in last 2 years, double the amount for total during my life and i'm 22), so i'm not worrying too much about our forests being robbed as forests are seen as a source of income that needs to be taken care of, not just exploited silly. the worrying thing is that people in (for example) amazonia just burn down some area of forest and farm on it for few years and then just move on, to burn more forest to be used for farming.

anything to cut down on fossil fuels is good anyways, at least as an alternative. what the article says is that old forests bind more co2 than young forests, which has nothing to do with it 'coming from dimension x' or something.

Re:Reduction in Co2?

[stephenbooth]

I think you're missing a fairly big hole in your arguement. Burning the nut shells will release C into the atmosphere, so will the rotting process. However burning the shells will mean that you will need to burn less oil and coal (C removed a very long time ago when there was a greenhouse effect in place due to the high levels of CO2 in the atmosphere) so you are reducing the overall amount of C released by putting the inevitable release of C due to the nut shells to use and reducing or eliminating the need to burn oil and coal.

If we assume that qualtity of C released from the nut shells (N) is the same for both burning and rotting, that the quantity of C removed from the atmosphere growing the nuts (P) is costant in both cases (we are talking about using a waste product of an existing industry here, not about growing the nuts as a fuel source) and the the burning of the nuts will provide the same energy as burning oil and coal that would release a quantity of C we label F then the quantity of C released to the atmosphere (A) will be for each scenario):

Rotting: A=(N+F)-P

Burning: A=N-P

Stephen

Nuts

[CGP314]

The power plant, located in Gympie, Queensland, is expected to reduce greenhouse gas emissions by around 9500 tonnes in its first year of operation.

In an unrelated story, macadamia nut consumption is up 10,000%

This is a failed experiment...

[shadowcabbit]

...after trying to harness the power of looney, wacky, zany, or crazy, they succeeded only in making use of nutty power.

Now if only...

[thesuperjason]

we could develop a plant that converted empty XXXX (local QLD beer) cans into usable power. Now that'd be something! Well, it'd ease my concience anyway...

Can you see the O'Reilly user manual?

[WIAKywbfatw]

Nutshell Power in a Nutshell.

I'm guessing it'd have a monkey on the cover. Or perhaps, sticking with the power plant theme, a picture of Homer Simpson eating nuts.

I know I'd pay good money for that book.

Yeah, cos macademia nut shells are a big problem

[Moderation abuser]

Unlike the thousands of tonnes of domestic rubbish we throw into huge steaming pits every day.

Efficiency?

[brucmack]

It would be nice to know what the cost efficiency of this plant is... seeing as how this has always been the big problem with "green" power.

Also, is there any inherent advantage to using macadamia nuts rather than some other biomass?

Re:Efficiency?

[Thomas M Hughes]

The main advantage in this case is that they were already growing the macadamia nuts in the area, and they were already shelling them. The shells were then, previously, just being discarded. Because the "fuel" for this power plant was previously considered "waste", the result is much more efficient economically then a lot of things.

Think of it like this:

macadamia = shell + nut

Old equasion:
profit = sale of nut - disposal of shell

New equasion:
profit = sale of nut + electricity generation from shell

This, of course, assumes that the electricity produced from the shells can be sold at a profit that is greater than the cost of disposing of the nuts. From everything I've heard here, the power plant is relatively inexpensive to construct ($3 million), as such, the cost of electricity generation probably won't be that great. However, we'd need more data to say that for sure.

As an added bonus, the CO2 output is neutral over a single year. Ie: shell takes 1 year's worth of CO2 in as it grows, we then burn it, and 1 years worth of CO2 is released. Comparatively, coal takes in X number of years (thousands of years ago), we burn it, and it releases it into the atmosphere now, resulting in a gain in CO2 in the atmosphere.

Keep in mind that this means we won't be powering the entire country with macadamia nut shells. This plant only powers 1200 homes. The brilliant aspect of this is that its powered off of waste that was already present in the region. This would be similar to a facility that produces corn creating a power plant next to it that is fueled by corn husks and the unedible parts of the corn. Its simply just a comparative advantage. Its fuel that you have here and now, so there are little to no transportation costs. Even if another biomass is more efficient, you'd have to transport it to the generation facility, decreasing its overall efficiency.

Ideally, for something like this, you'd build lots of smaller facilities, wherever burnable bio-waste is produced. 1200 homes here, 1200 homes there, mix it with some solar and wind generation, and other alternative energies, and eventually the fossil fuel habit might be kicked.

Energy in/Energy out.

[CGP314]

How much energy goes into getting the nuts out of the shells in the first place? I remember going to a macadamia nut farm in Hawaii once. They had a prize of a lifetime supply of macadamias if you could get a nut out of a shell without using a saw. I tried smashing it with a rock with no luck. Apparently, no one had ever collected the prize.

Re:Energy in/Energy out.

[deek]

• How much energy goes into getting the nuts out of the shells in the first place?

I've visited a macadamia farm, and seen the machine that they use to remove the shells. It resembles something like an engine, with rows of levers catching the nut and compressing it just a few millimeters. The shell is very brittle and cracks completely if you can compress it just a little.

• They had a prize of a lifetime supply of macadamias if you could get a nut out of a shell without using a saw. I tried smashing it with a rock with no luck. Apparently, no one had ever collected the prize.

I can't say I'm surprised. I regularly crack open macadamia nuts. Handheld nutcrackers are useless. I've actually broken the nutcracker before I've broken the nut. My method involves an irresistable force and an immovable object (who said that theoretical physics wasn't practical?! 8)) . But seriously, I use a hammer and a rock slab. I literally have to pound the nut a good three or four times with the hammer. And I mean serious swings ... with the kind of force you need to drive a nail. But the nut always gives way, and on rare occasion, the finger too (ouch!).

Whoever came up with the phrase "a hard nut to crack", obviously worked in the macadamia business.

DeeK

Rogue Nation

[Potor]

How did they get the technology to split the nut?

Re:Rogue Nation

[Mattcelt]

Well, basically, they take another nut and shoot it at high velocity at a group of nuts. (This group must be large enough to have a "critical mass".) When the accelerated nut hits the group of nuts, it breaks, sending portions of its innards (the meat, in technical terms) into the other nuts, which break open other nuts, which cause them to release their meat, with each nut releasing its potential energy in an ever-increasing "chain reaction".

But they need to control this highly dangerous process, so they use a fluid which surrounds the nuts to slow the reaction at the edges of the mass. They looked for a long time before they chose just the right formula, but they've settled on a standard, something physicists call "dark chocolate".

The major byproduct is a nutmeat-filled candy bar called "Hershey's", named after the scientist/confectioner who invented the process. While highly dangerous to a small portion of the population, most people are only subject to a small subset of detrimental effects.

In related news, recently the doorways in the plant had to be widened considerably to accomodate the plant's regular staff, who seem to have taken to eating the power plant's byproduct.

Thats nothing

[mphase]

Watch this process turn your garbage into oil.

Higher usable energy

[moscow]

According to ABC Queensland , Macadamia shells are actually prime material for electricity generation - they burn more cleanly than coal, and produce more energy.

Of course, natural decay of the shells would release the CO2 in any case.

Re:The article doesn't say...

[madbastd]

But does anyone know why they chose macadamia nuts? Seems a very strange choice.

Macadamia trees are a native plant in that part of Australia, and grow very well. There's a large macadamia nut industry there, which was throwing out huge amounts of nutshell.

Hello, 1970?

[heironymouscoward]

This is the scene. I'm a young boy, 8 years old, in Dar-es-Salaam, capital of Tanzania. On the horizon sits a squat building with a tall tower, belching some kind of gray-white smoke.

"Mummy, what's that?"
"It's a power plant, Heirony"
"What does it burn, Mummy?"
"Caschew nut fruits, Heirony"

The caschew nut grows as a small nut on a huge fruit which is rich and oily. For each of those tiny caschew nuts, a fruit weighing perhaps 500gr is grown, harvested, and then discarded.

In Tanzania in 1970, and probably still today, these fruits were dried and then burnt for power. Glad to see that some third-world technology had finally made it to the rich west.

I'll be here all week.

[Docrates]

So, in a Nut shell, there's a lot of energy.

Other biomass/CO2 neutral examples

[Zog The Undeniable]

There are biomass power stations in Europe that use willow as a fuel. Willow trees grow very quickly and, as has been done for centuries, can be "pollarded" to remove the last year's growth for fuel without killing the tree. These plants are CO2 neutral. over the timespan of a year. Biodiesel, which works in the majority of new diesel cars, is also CO2 neutral because it comes from quick-growing crops such as soya beans.

All this makes more sense than GWB's hydrogen economy, which needs electricity to make the hydrogen. As electricity generation is about 30% efficient, there's not much point in using biomass to produce hydrogen for fuel cells - you might as well stick biodiesel straight in the car.

Re:Other biomass/CO2 neutral examples

[panurge]

In fact, why aren't we trying to replace 3rd world drug crops with biomass fuel crops? Support poor farmers, reduce dependence on imported oil, benefit the population as a whole rather than the drug cartels and the oil company executives...oops, there went the economies of Florida and Texas. Why don't I think it's going to happen? Because biomass is good for the public, but it's bad for the bushes.