[lorenzo]

Hi, I have some great inside information (thank you Lorenzo for this scoop). Next week, scientists will publish a letter to "the governments in Bali" (and to the public at large), in which they call for the promotion of carbon negative bioenergy and biofuels.

With these fuels you can actually take carbon dioxide out of the atmosphere and avoid catastrophic climate change.

Renewables like wind or solar, and nuclear and other so-called clean forms of energy are "carbon neutral" at best. They don't add "new" emissions to the atmosphere (in reality they do add small amounts over their entire lifecycle). But with the prospect of catastrophic and abrupt climate change this is too weak an offer.

Therefor the scientists will be calling for a far more radical energy concept, to know: carbon negative biofuels and bioenergy.

You obtain these by coupling biofuel and bio-electricity production to carbon capture and storage (CCS) - you capture and lock up the carbon dioxide before it enters the atmosphere - either in soils in the form of agrichar, or in geological sites like depleted oil and gas fields or saline aquifers.

This way, when you use this energy, you effectively take carbon from the past out of the atmosphere. Negative emissions! Projections show that if implemented on a global scale ("geoengineering" scale) today, we can reduce atmospheric carbon dioxide levels from the current 425ppm to pre-industrial levels (270ppm) by mid-century, and avoid catastrophic climate change.

Compare:
-a kilowatt of electricity from coal results in 800 grams of CO2
-gas combined cycle: 500 g/kWh
-gas & coal with carbon capture and storage: 100 g/kWh
-photovoltaic: 100g/kWh
-wind power: 20-50 g/kWh
-nuclear: 10-30 g/kWh
-bioenergy with carbon capture and storage: -1000 g/kWh!!!

You read that right: minus a thousand grams!! Negative emissions!!!

They will say that the time has come for this most radical of concepts and that the post-Kyoto framework should give it absolute priority.


Negative emissions can only be gotten from biomass (because it acts as a machine that captures CO2). Other "geoengineering" options to take CO2 out of the atmosphere don't generate energy and have been dismissed as too risky: iron seeding the oceans to cause algae blooms (won't work and could be very damaging), emulating the cooling effects of a volcano by seeding the atmosphere with sulphur, etc... way too dangerous and risky.

Carbon negative biofuels and bioenergy in contrast offer a safe, efficient and low-risk geoengineering strategy.

So watch out next week!

[lorenzo]

$this->bbcode_second_pass_quote('pstarr', 'L')orenzo would you mind sharing the original science with us. The science that promotes these incredible energy and carbon savings. I would just so much like to see the data and methods. and stuff.

[americandream]

I'ld like some of what you're smoking to keep me busy this weekend.

[highlander]

How about starting a fund to buy Lorenzo some books.
Lets start with "physics for dummies"

[Aaron]

[lorenzo]

So what exactly don't you understand about the concept?

[Narz]

If I didn't know any better I'd swear you hecklers want the world to be destroied and the lifes of human beings to be turned to s***.

[Andrew_S]

$this->bbcode_second_pass_quote('lorenzo', 'T')herefore the scientists will be calling for a far more radical energy concept, to know: carbon negative biofuels and bioenergy.

You obtain these by coupling biofuel and bio-electricity production to carbon capture and storage (CCS) - you capture and lock up the carbon dioxide before it enters the atmosphere - either in soils in the form of agrichar, or in geological sites like depleted oil and gas fields or saline aquifers.

This way, when you use this energy, you effectively take carbon from the past out of the atmosphere. Negative emissions! Projections show that if implemented on a global scale ("geoengineering" scale) today, we can reduce atmospheric carbon dioxide levels from the current 425ppm to pre-industrial levels (270ppm) by mid-century, and avoid catastrophic climate change.

[Valdemar]

So, a large scale programme to switch over to bio-fuels and bio-electricity that not only is neutral, but reduces carbon and carbon equivalent output?

Why don't I believe that? I, too, would like a nice concise explanation of the workings of such a project, rather than wade through numerous papers that, from what I can see, have had no impact on things thus far.

[efarmer]

Doggone it Lorenzo. I was reading through that laundry list answer of yours to Pstarr and forgot I had food on the stove.
I'm heading outside to sequester my first big batch of biochar in a little while. I admire your optimism and believe it is a good thing to set a high goal as well. But there is a danger in putting optimism on steroids, it tends to convert it into fantasy.
I hope if scientist really do aim for carbon negative, they at least pull the trigger and hit lower carbon or carbon neutral first.

[lorenzo]

The concept really isn't that difficult to understand. It is the combination of producing bioenergy with carbon capture and sequestration. There are two ways to do this: a high tech and a low tech route.

"HIGH TECH"
1. if you produce bioenergy, say electricity and heat from biomass, you do a "carbon neutral" operation: you grow biomass, burn it, it releases CO2, which is taken up again by the new biomass.

Of course, no renewable is ever an entirely carbon neutral operation, because you emit some GHGs during the harvesting of the biomass and the construction of the plant, or during the manufacture of wind turbines, etc...

But for the sake of clarity, let's call these classic renewables like wind, biomass or solar "carbon neutral".

2. electricity from fossil fuels is "carbon positive": you emit GHGs during their combustion.

3. the coal & gas industry are looking at reducing these emissions. How? By capturing the CO2 before, during or after the combustion of the fuel, and by then transporting and storing this CO2 into geological formations, such as depleted oil and gas fields, or saline aquifers. This process is known as "carbon capture and storage" (CCS).
Emissions can be reduced considerably, but can of course never go below zero. Coal + CCS makes the electricity "carbon neutral" at best - no new emissions into the atmosphere.

4. Now if you couple CCS to bioenergy production you obtain "carbon negative" energy.
Why? Because your biomass crops take CO2 out of the atmosphere, but when you burn them in your power plant, and consequently capture and sequester the CO2 in geological formations, you effectively take more CO2 out of the atmosphere than you put in.
You alter the carbon cycle and you take emissions from the past out of the atmosphere.

This is "carbon negative" energy. It's not so difficult to grasp, is it?

How do you capture CO2? There are three basic pathways:
1. capturing it before you burn the fuel, by first gasifying it so that you obtain a carbon monoxide and hydrogen rich gas, which you reform (via water shifting or other methods) so that you obtain a separate stream of CO2; you can then burn the decarbonized fuel, as hydrogen, in a gas turbine, and capture the CO2.
2. capturing it during the combustion (oxyfuel combustion)
3. capturing it after the combustion, sifting it out of the flue gas, with membranes and other technologies.

A special case is the production of carbon negative bio-hydrogen: you ferment biomass into hydrogen, which releases a pure stream of CO2, which you can then capture in a pretty straightforward way, without the need for the gasification step.

Finally, you can produce biogas in such a way that you obtain a larger than 50% CO2 fraction; this is quite easy to capture; after you have separated the CO2, you obtain pure methane, which you can then reform into hydrogen. During this step, you again take out the CO2 and add it to the already captured, large fraction of CO2 from the biogas; you then transport and put all this gas under the ground.
The end result: hydrogen with a negative carbon balance.


But let's stick to the most straightforward way to generate "negative emissions": producing bio-electricity with Carbon Capture and Storage (CCS).

-The emissions from ordinary coal electricity are around 800 grams of CO2 per kWh
-The emissions from ordinary coal electricity but with CCS are around 100 grams of CO2 per kWh (you can never get to real "clean coal" because you always need some energy to drive the CCS process)
-The emissions from ordinary bio-electricity are around 30 grams per kWh (this is commonly seen as "carbon neutral", in reality slightly "carbon positive")
-The emissions from bio-electricity with CCS can be up to -1000 grams per kWh (yes, that is: minus 1000 grams).

$this->bbcode_second_pass_quote('', '[')Figure 3] illustrates the concept. Atmospheric CO2 is adsorbed by growing biomass which is then used to produce electricity. If the CO2 produced is returned to atmosphere, the process is essentially carbon-neutral (typical emission factors for biomass energy schemes are in the range 10-20 gCO2/kWh; c.f. about 800 gCO2/kWh for a modern coal-fired power station). However, if the CO2 produced by burning biomass is captured and permanently stored, e.g. in an underground geological formation, the overall process would result in a net removal of CO2 from the atmosphere.

[Andrew_S]

Thanks, lorenzo, for your good overview. I shall now take the trouble to read the references.

[Valdemar]

Indeed. I am interested to know more now and see how this progresses, if at all.

[steam_cannon]

$this->bbcode_second_pass_quote('lorenzo', 'S')orry, I cannot explain the concept in any simpler way. Hope you get the basics of it now.

[steam_cannon]

Different names for the same thing: "biochar" or "agrichar" or "terra preta"
Apparently it does make a good fertilizer and stays in the soil a long time...
$this->bbcode_second_pass_quote('wiki', 'O')rigin of terra preta

For a long time, the origins of the Amazonian dark earths were not immediately clear and several theories were considered. One idea was that they resulted from ashfall from volcanoes in the Andes, since they occur more frequently on the brows of higher terraces. Another theory considered formation as a result of sedimentation in Tertiary lakes or in recent ponds.

However, because of their elevated charcoal content and the common presence of pottery remains, it is now widely accepted that these soils are a product of indigenous soil management involving a labor intensive technique termed slash-and-char. The technique is differentiated from slash and burn by a lower temperature burn and in being a tool for soil improvement. Amending soil with low temperature charcoal produced from a mix of wood and leafy biomass (termed biochar) has been observed to increase the activity of arbuscular mycorrhizal fungi. It is theorized that terra preta self-propagates via this mechanism; a virtuous cycle established as the fungus spreads from the charcoal, fixing additional carbon and stabilizing the soil with glomalin, and increasing nutrient availability for nearby plants. The widespread peregrine earthworm Pontoscolex corethrurus (Oligochaeta: Glossoscolecidae), which thrives after burning of the rainforest, due to its tolerance of a low content of the soil in organic matter, has been shown to ingest pieces of charcoal and to mix them in a finely ground form with the mineral soil, pointing to its possible role in the formation of terra preta.

About 10% of the original terra comum appears to have converted to terra preta. Whether all Amazonian dark earth was intentionally created for soil improvement or whether the lightest variants are a by-product of habitation is not clear at present time. This is in part due to the varied features of the dark earths throughout the Amazon Basin. Thus suggesting the existence of an extensive ancient native civilization dating back 500 to 2500 years bp.

http://en.wikipedia.org/wiki/Terra_preta

[eastbay]

Does this mean humans can continue to manufacture 50 million cars (with a 5% annual growth rate) annually?

And produce around 2,000 commercial passenger aircraft annually too?

Plus maintain a fleet of tens of thousands of commercial seagoing vessels in operation?

[lorenzo]

$this->bbcode_second_pass_quote('eastbay', 'D')oes this mean humans can continue to manufacture 50 million cars (with a 5% annual growth rate) annually?

And produce around 2,000 commercial passenger aircraft annually too?

Plus maintain a fleet of tens of thousands of commercial seagoing vessels in operation?

[eastbay]

Ok, just so I understand you correctly:

The 750 million passengers who flew on domestic airliners within the USA on 11 million commercial domestic flights and the uncountable millions of interstate truck runs and and billions of passenger car trips across state lines in the year 2005 could all take the train instead.

That's what I'm talkin' about. Avoid the radical stuff. I'm down with that.

[steam_cannon]

$this->bbcode_second_pass_quote('Narz', 'I')f I didn't know any better I'd swear you hecklers want the world to be destroyed and the lives of human beings to be turned to sh!t.