Meet the Black Phantom, the Huge Microwave Oven That Fights Climate Change

By Eliza Strickland | March 13, 2009 3:58 pm

charcoalA climate scientist in England has invented a new process for turning wood into charcoal with giant microwaves, and says that the technique may be the best tool humans have for sequestering carbon and slowing global warming. The “biochar” created in the process locks in carbon from the wood, and sequesters it for thousands of years before the charcoal finally decomposes.

Biochar received new attention recently when researchers ranked geoengineering schemes based on their ability to slow global warming, and listed biochar as one of the most effective (and cheapest) approaches. The English scientist, Chris Turney, is eager to move from theory to practice, and has founded a company called Carbonscape that set up a microwave-powered kiln in Blenheim, in New Zealand’s South Island, in October last year…. The stove the Carbonscape directors call the Black Phantom can fix up to one tonne of carbon a day [The Australian].

Charcoal is typically produced by slowly heating wood in industrial ovens, but Turney says his microwave process is cleaner and more efficient. The idea came from a cooking accident when he was a teenager, in which he mistakenly microwaved a potato for 40 minutes and found that the vegetable had turned into charcoal. “Years later when we were talking about carbon sequestration I thought maybe charcoal was the way to go,” he said [The Guardian].

Turney says that if biochar operations are adopted across the globe, the technique could take out billions of tonnes of CO2 from the atmosphere every year. Fast-growing trees such as pine could be “farmed” to act specifically as carbon traps — microwaved, buried and replaced with a fresh crop to do the same thing again [The Guardian]. He notes that traditional methods of producing charcoal convert only 20 to 30 percent of the wood’s mass into charcoal, while his process can lock in about 50 percent.

There’s another upside to biochar: It could also be tilled into the ground to make soil more fertile. Its porous structure is ideal for trapping nutrients and beneficial micro-organisms that help plants grow. It also improves drainage and can prevent up to 80% of greenhouse gases such as nitrous oxides and methane from escaping from the soil [The Guardian]. Archeologists think that Amazonian people were using biochar to improve their nutrient-poor soils by 400 A.D., and possibly hundreds of years earlier.

Related Content:
80beats: Ancient Agriculture Trick, Not Hi-Tech Engineering, Is Best Climate Defense
Discoblog: The Softer Side of Climate Control?
DISCOVER: Black Gold of the Amazon, a look at how pre-Columbian South Americans used biochar agriculture

Image: Wikimedia Commons

  • UncleAl

    Wood is cellulose, polyanhydroglucose ( C6H10O5)n, plus some lignin around C9H10.4O3.6 that is 24–35 wt-% softwood dry weight and 17–25 wt-% hardwood dry weight. Go for 72 wt-% cellulose and 28 wt-% lignin for C6.8H10O4.6, average MW = 165.35 49.4 wt-% carbon, 6.1 wt-% hydrogen, 44.5 wt-% oxygen for absolutely dry wood (10 wt-% water at atmospheric equilibrium,

    traditional methods of producing charcoal convert only 20 to 30 percent of the wood’s mass into charcoal, while his process can lock in about 50 percent.]

    How about is “about”? Is it about 100% conversion on anhydrous high-lignin wood? One tonne of fixed carbon/day hardly cancels fossil fuel electricity to run the microwave oven. 2000 global wood harvest was 3.35 billion cubic meters massing about 1.88 billion tonnes then holding 0.938 billion tonnes of carbon equal to 3.4 billion tonnes of CO2.

    billions of tonnes of CO2 from the atmosphere every year

  • Darr Sandberg

    What would be really useful is a way for everyone to do this at home, without radically increase our use of electrity. Imagine if you could just biochar your leftovers each evening, and in the spring, till it into your backyard garden or lawn, or donate it to the city park.

    These big mega projects are not bad ideas, but we also need lifestyle changes everyone can do, to involve everyone possible in undoing centuries of something we’ve all been doing.

  • Darrell

    I agree^

  • mj233

    Any one of the thousands of active volcanoes put more greenhouse gas into the air in a single day than a modern coal fired plant does in 100 years. You people are either nuts or a bunch of hysterical fruitcakes… I got your lifestyle change right here, buddy…..

  • Wisco

    Perhaps I am missing something, but where does the power for these giant microwave ovens come from? Is there a bunch of low-cost, non-CO2 emitting electricity sitting around somewhere?

    Re: Volcanoes. Yes, of course they add to the atmosphere, but at a geological timescale their contributions of greenhouse gasses have been roughly “balanced” such that the planet rarely experiences a catastrophic change in climate. Our burning of fossil fuels ADDS ON TOP OF that background volcanic contribution to tip the scales in a direction that is unlikely to yield desirable consequences for global human populations. If you think that the trillions of tons of CO2 stored away in coal and oil can be placed into the atmosphere with minimal effect, you are either stupid or an industry shill.

  • mRogers

    I don’t see how this could be workable with the current energy infrastructure. Like much of the world, in the southeastern US most of our electricity is produced from COAL. So we burn coal to make electricity to run a giant microwave to make……coal? Efficiency leaks will insure that you’re far in the red on that carbon transaction. And if you’re going to make your product available to farmers to till into their soil exactly how do you prevent its diversion as a low grade fuel or purchase by charcoal briquette makers either of which would cut your carbon sequestration quite short. Or is this ultimately an elaborate way for carbon credits to subsidize the backyard barbecue?

  • AzureRaptor

    I wonder if it’d be possible to use a process similar to this, but use something like a giant fresnel oven for the heating. Possibly with a filter to only let certain wavelengths of light through for the most efficient heating. It might need to happen in some kind of sealed chamber to capture offgassing, but there also might be a way to hook up a low-energy/high-efficiency blower and filter or pump system to capture that, so you’re still net-carbon positive. Hopefully the process would scale up to greater efficiencies.

  • JDH

    What the heck? This is ridiculous on every level.
    Plant trees, cut them down and carbonize them.

    We cant reforest shite right now. What makes people think we could geo engineer this way?
    I mean aside from the “free energy” microwave nonsense.

    If we reforested the planet to 1900 levels that might be enough but nobodies listening.

  • John

    Let me get this straight, volcanoes have been pumpiing carbon, methan, etc. into the air since the mass of the planet got big enough to create these geophysical structures. There are currently volcanoes spewing out “greenhouse” gases and there have always been active volcanoes. Somehow you think that 3.7 million years of this activity has been greatly increased on in the last 200 years of industrial contributions. Even with that said co2 only makes up a small portion of the atmosphere and most “intelligent” studies have found that the “sun” is the single major causal driver in what has always been an ever changing climate. But I do think that we as a species can do things in a better way to prevent pollution not global catastrophic failure…”the sky is falling, help Al Gore, help maybe with a breathing tax….”

  • YouRang

    I may have missed it in the comments above; but it seems to me a better use for the char machine would be to convert biological waste into fuel for electric plants. If we didn’t have to worry about the pollution, we could already be using leaves, brush, roadway construction debris for fuel in lieu of coal.
    And you people who totally miss the point about co2′ contribution to global warming. There may be a lot more of other gases but co2 has absorption/emission bands in the right energy range for absorbing/back emitting to the ground. I might point out that co2 is expected to warm the lower atmosphere; but since it’s such a great emitter, you would expect it to cool the upper stratosphere.

  • YouRang

    One other item not mentioned: The greatest soil conditioner is not humus but charcoal. Unlike humus, it doesn’t degrade readily or be metabolized. The indians in the Amazon rain forest just before Columbus actually had a thriving culture despite the normal poorness of rain forest soil. They practiced a valuable variety of slash and burn. Instead of just burning the trees for clearing– a process in which the soil is depleted about as soon as it’s cleared–they charred the wood. Of course, no one has been advocating that kind of process just because someone has to inhale the smoke from the charring wood; but if anthropologists could get them to char in an appropriate oven?

  • Hydrophilia

    And use the biogas driven off as a fuel rather than letting it pollute?

    Still, digging coal from the ground and burning it while making charcoal and burying it does seem silly. Although the different structures of charcoal and coal make charcoal a lot better to add to the earth than coal. So, if we stop burning coal and remove atmospheric CO2 with biochar, as long as we can create it efficiently and cleanly, we might have a winner: better soil, less CO2 in the air, possibly a good fuel or chemical feedstock from the volatiles…

  • Luis Enrique

    so, how many solar panels would be needed to power one of these, and what is the estimated cost (including some amortised capital expenditure, costs of getting the biomass then storing the charcoal) of sequestering 1 tonne of carbon this way?

  • Jason

    When charcoal is produced methanol, hydrogen and carbon monoxide are off gassed. These could be run through a ceramic fuel cell to produce power and offset the energy used for the microwave. The waste heat from the fuel cell could be channeled into the incoming material with the use of a heat exchanger to make the overall process more efficient.

  • nparikh

    Think of all the pine trees that are cut down every year for Christmas and then discarded a few weeks later. Instead of trashing them we could char them. That is already an existing tree farming operation on a fairly large scale, at least in the US.

  • seer

    Comments about taking various biomass and charring it, or using it for energy, overlook the soil building contributions of the biomass. Always remember: nature doesn’t waste!

    Trying to speed up natural processes ALWAYS costs energy. Using electricity from coal-fired power plants is, I agree, absurd: there’s no way that you can offset the CO2 releases from all activities associated with mining, processing, hauling and burning the coal: and this doesn’t include all the accounting for the machinery necessary to accomplish all of this, nor the environmental toll!

    Getting back to the notion of using biomass as an energy source… biomass isn’t as energy dense as our current fuels of choice. Collecting up and processing biomass is no small task! The further that you have to haul this lesser return on investment (be it money and or energy), the closer you come to energy deficits (if not already starting from a negative position!).

    Most of these schemes take advantage of ignorance, and the notion that technology can actually save us (when technology is only a process: people confuse it as being able to produce resources). All people should be familiar with Jevons Paradox.

  • Hawk Hogan

    I prefer using more efficient microwaves to cure recyclable materials such as tires and other waste into fuels through a closed loop oxygen depleted environment and without emissions.

    I prefer not to impact living organics especially food sources to extract fuels from and use the carbon ash from that process for CO2 absorption materials.

  • nick

    The point with biochar is that it should be considered as a solution for many aspects; primary feedstock should be waste products, agricultural biproducts such as rice husks, peanut shells, pine needles, xmas trees, animal bone and even excrement.

    The pyrolysis process uses energy to convert the feedstock to charcoal, but also releases a variety of useful biofuels (oils and gases) that can be captured and used for their energy.

    The charcoal is a wonderful soil amending substance that has provided startling results in trials, significantly boosting yields, reducing the requirement for fertilizers and water for irrigation, whilst also maintaining the quality of the soil and preventing desertification.

    If implemented properly, it is almost a miracle solution to so many problems environmental problems.

  • Larissa

    I think that the idea is to cook the wood in the absence of oxygen, which prevents the formation of CO2, and locks the carbon away. My issue with this idea is that it is sold as getting rid of agricultural waste, instead of it “rotting in the field”. The trouble is that the rotting vegetation provides nutrients for the next season, and without it they will need fertiliser, which is very CO2 intensive.


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