Durability Uber Alles

For much of the XX century Western Civilization bowed to the god of profit above all else. Externalities were vehemently, sometimes violently ignored. This mode of thinking brought many, though certainly not all, a vastly more comfortable lifestyle. Meanwhile many planetary systems upon which humans and most other flora and fauna depend suffered greatly. Unchecked pollution of water, air and soil exacerbated biodiversity loss triggered by converting vast swaths of forests to farmland around the globe.

As we round out the first quarter of the XXI century, profit still reigns supreme nearly everywhere though carbon is (finally) beginning to nudge its way into the balance sheet of more and more governments and corporations. Sadly, it looks like we may repeat the ill-begotten singularity of focus with carbon as was done with the god of profit.

The emerging myopic focus being lauded most loudly is known as ‘permanence’ (aka durability). While preventing carbon from converting back into carbon dioxide for as long as possible is definitely a most admirable trait, it should not be viewed as the only trait of relevance.

Curiously (or not if you follow the money behind it) permanence seems to be all everyone is talking about these days. It has begun to outweigh any and all other considerations and criteria for supporting certain carbon removal strategies. Somewhat arbitrarily it seems to have been determined by many influential carbon removal buyers that 1,000 years is the new holy grail for durability, though others acknowledge that removing carbon from the carbon cycle for a century or even a decade has value and should be valorized.

Consideration as to when these removals will actually happen is barely discussed. Given the intense and earnest messaging around how critical the next decade (or less) is in terms of averting the worst impacts of the climate crisis, one might think near term delivery and scalability would factor in at least as high as durability.

Considering all of the other critical problems humanity is facing such as increasingly depleted and toxic soils, our ability to feed a burgeoning population while adapting to the many new climate vagaries, competition for ever scarcer resources, and the need to shift quickly and cost effectively away from our dependance on fossil fuel energy, one might think that co-benefits of carbon removals such as those provided by reforestation, afforestation and biochar would factor at least as high as durability when considering what CDR to invest in.

Considering the mounting mountains of unloved organic materials from sewage sludge to food waste to excessive forest residues looking for safer, end-of-life options, one might think win-win (or even win-win-win) solutions that convert problematic organics into carbon removal opportunities would factor into decisions about what carbon removal strategies should be selected and funded.

At such a critical juncture in human history, all removal solutions should be on the table. That should go without saying. But in a time and resource constrained world, prioritization is paramount. What is doable now and how do we scale it cost-effectively should be at the forefront of investment decision making. Climate change mitigation, while exceedingly important, is not the only crisis needing our immediate attention and funding. Likewise, carbon permanence is important, but it is far too simplistic (and dangerous) to focus so much attention on this aspect to the detriment of all others. (What is that expression about all eggs in one basket?) Complex problems require more than a single, overarching focal point or rallying cry. We can and we must learn from the lessons learned from focusing solely on profits. If we don’t the suffering experienced over the last century will look like child’s play compared to what we will experience in the coming decades.

Decarbonizing Coffee

I have been fascinated by the challenge of decarbonizing coffee for many years. Initially this took the form of diving deep into the research literature on biochar and coffee combined with scanning the globe to see who was doing what with biochar in the real world of coffee growing, milling, roasting and ‘merching’. This culminated in a 2015 white paper which was later updated in 2018. A few years later I started working with some very forward-thinking folks at CarCafe (a subsidiary of VolCafe which is owned by ED&F Mann a global food company) to figure out low-cost, low-tech ways to reduce GHG emissions at small-holder farmers – mostly focused on improved residue management and reduced fertilizer use which is where the vast majority of emissions come from on farms (and a recent study showed that roughly 44% of the entire supply chain emissions are at the grower/milling stages).  Over the past few years, we’ve taught 100+ farmers plus a hotshot group of ‘tecnicos’ (agronomists -mostly- that help farmers to grow more efficiently and sustainably) how to make and use biochar on the farms.  

Most recently I was invited by a friend who formerly headed up a protect at Coop Coffees, an organic coffee trade organization, to attend a gathering in Jaen, Peru with various coffee cooperatives that had gone through a multi-year GHG benchmarking process for 250 smallholder farmers in several LatAm countries. Ostensibly I was invited to introduce them to biochar and how it could help reduce emissions. As it turns out a few of them are well on their way on their own biochar journey and ‘francamente’ (this seems to be an oft used word in Peru which made me smile when I started counting how many times it was used!) it was inspiring to learn more about what they are doing. How could I not share their biochar stories at least a small part of them?

Sol y Café is an impressive coop with more than 1000 farmer partner/owners. While coffee seems to be their mainstay, selling ~200 truckloads per year, they have expanded into cacao, aquaculture on a few farms, and at their central hub they now have an elementary school and small-scale livestock farming (i.e., rabbits, guinea pigs and apparently a somewhat mythical creature which is half goat, half sheep (as with donkeys they cannot reproduce). They make their own EM1 formulations and other fertilizers and soil amendments, they have an impressive coffee tree nursery and a good-sized vegetable garden which grows food for the school and worker’s cafeteria. They also have the tiniest alfalfa field I have ever seen which grows food for the bunnies and guineas.

I gave a short demo on how to produce biochar from a variety of unused biomass found at the central coop and discussed various ways they could use it. Turns out, however, they are already experimenting with a LOT of biochar made from coffee parchment by another coop in the region, Norandino. This small scale, continuous feed machine was recently fabricated in Peru in collaboration with Swiss engineers and has been used to carbonize both coffee and cacao residues. Our Sol y Café hosts showed us the various ways they have been experimenting with the parchment biochar, a very light-weight, consistently small sized type of biochar. To be honest I have never seen so much biochar used in such a small space and I was (francamente) curious as to why they used so much of it as the soils, at first glance, seemed quite dark already. Looks can be deceiving apparently as they told us their veggie plots were rice paddy fields not so long ago and are heavily cracked hard pan soils laden with salt and excess calcium. They were on a quest to remediate these issues organically and were hoping biochar could help. Given they had received a lot of biochar at no cost (for now!), they decided to go big! For each half row, they used 5 ‘quintales’ (coffee sacks) of pure biochar then blended it with homegrown compost. It doesn’t appear that it was tilled into the ground, but they seem fairly protected from erosion and there is a sunscreen overhead. I wish they had done controlled trials which may happen in the future but after several weeks the plants seem very productive, and the Sol team seems quite happy with the growth as well as reduced need for watering.

Prior to receiving the parchment biochar, they apparently learned how to make small amounts of biochar from another coop in Honduras, Comsa, that has an unusual way of making biochar which I have not seen and am still waiting to learn more about it. Comsa also taught the folks at Sol about EM1 and their on-site international school was the model for the recently built one at Sol. This type of collaboration versus competition was so refreshing to see. It is definately the way to spread ideas quickly so you can iterate on customizing what works in different cultures and share improvements.

At the end of my short biochar production demo, I asked the 2 – 3 dozen folks if there was interest in on-farm biochar production and I do believe there is interest, not only as a way to upcycle residues but also to reduce fertilizer purchases. As prices have skyrocketed over the past year, farmers are looking for all manner of ways to reduce their dependency on fertilizers, organic or otherwise. The great side benefit is that the biochar they make and use to reduce fertilizer can help them to both mitigate and adapt to climate change. And soon, very soon, through the Artasanal C-sink methodology being finalized by Carbon Standards International, smallholder farmers that make their own biochar from on-farm residues and use it on their farms, will be able to tap into the ever-expanding carbon removal marketplace.

[NOTE: my Spanish is rusty so I am still verifying a few things I thought I understood from various conversions so I may have to update a few parts of this post!]

Dwelling on Drawdown Part IV – About Grout (with biochar, of course!)

I absolutely love it when I come across contractors willing to consider more sustainable ways of doing things. Too often in my Dwelling on Drawdown (D0D) home-building journey the opposite has been my experience. But recently when I had my shower floor installed by Charlie B from Skip’s Custom Flooring, not only was Charlie willing to consider using biochar in the project, he was downright enthusiastic! I was a bit shocked to find out he’d been reading up on biochar for years and was hoping to build a kiln to char through lots of tree debris on his acreage. (Biochar is still mostly unknown in my part of the world.) We discussed possible ways of using biochar on this small project and tested it as a tint for the grout. Charlie also had other ideas about how biochar could be used in buildings but also knew that it is likely used in certain types of pottery (see La Chamba pottery from Colombia, or Raku from Japan). That was news to me – yet another tantilizing biochar rabbit hole for exploration.

The grout sample dried nicely so we mixed up a batch to use on the 48sf shower floor. It took a lot more biochar than I thought we’d need and we never got it to turn black though that wasn’t really my intent on this project. Roughly one pound was added to 2 gallons of grout . I’ve used Aries Clean Technology’s powdered biochar for other D0D projects and was a little surprised that it didn’t turn a darker shade of grey as it definately tinted my walls a very dark black as I’ve written about before. The only difference Charlie observed was that the mix was a bit ‘greasier’ than a more commercially available tinted grout, meaning it was slightly more difficult to wipe off the tiles when grouting was finished.

Black iron oxide or magnetite is what is commonly used as a black tint for grout and a whole host of other materials. Both natural and synthetic types are used in everything from construction materials, paints, coatings, and plastics, cosmetics, pharmaceuticals and even ceramics, and toners (Pfaff 2021). Imagine if we could start displacing some of that with different types of biochar?! We just need to understand the tinting abilities of different types of biochar across they gray to black spectrum. On our recent EPA project focused on using biochar in drywall we observed quite a variation in coloring based on feedstock types, particle size and obviously amount used.

How else could biochar be used in bathrooms? The plan for the shower walls is tadalakt plaster with a just a touch of biochar to tint it a lighter shade of gray. I’ve tested it out and it works great with a wide variation of grays possible (see picture). Next up though is my sink vanity top which is being custom made using epoxy and biochar. The epoxy artist has already done a test run and is now very interested in using biochar as his black tint is about $60 per pint! More on that soon.

[I know my BURN co-author would remind me that it can be used in composting toilets. Though I I didn’t go that route for my Dwelling on Drawdown, I do have an ‘emergency’ toilet in the basement with biochar in a bucket!]

Biochar’s debut at the United Nations

Two minutes. Two whole minutes to introduce biochar to United Nation’s delegates from around the globe. Far too little time but at least it was on the agenda of the 7th multi-stakeholder ‘Science, Technology and Innovation for the UN Sustainable Development Goals. Thematic session 5, the one I was asked to join as a ‘discussant’ (had to look up what that meant), was focused on ‘Emerging carbon dioxide removal (CDR) technologies for addressing climate change’.

In addition to a high level (very high level, remember two minutes!!) overview of your particular CDR, panelists and discussants were asked to address one of the five guiding questions used for the session which included:

  1. CDR technologies are needed at the local (industrial or power plant), national (NDC), and global scale (reaching net zero global emissions). What partnerships are best at each level?
  2. For companies and funders– how do you plan to scale up your technologies to make a difference at the global scale of 1-10Gt/yr?
  3. How can we better support the innovation ecosystem around these technologies?
  4. How can the UN contribute to a showcase of emerging demonstration projects and best deployment practices of CDR technologies?
  5. How can the UN contribute to a responsible discussion of the potential consequences, costs and trade-offs of various technologies, their interactions with various SDG goals, and their ethical and governance issues alongside conventional mitigation and adaptation strategies?

It’s always interesting to prepare for different audiences but being given such a short period of time, I had to hone my biochar ‘elevator pitch’ down to this:

Biochar is likely the oldest anthropogenic CDR solution yet few have ever even heard of it. Indigenous cultures across the globe figured out thousands of years ago how to carbonize biomass and fill it with nutrients to enrich soils and feed growing populations.

Biochar is safe, scalable and shovel-ready. It is already being produced by smallholder farmers in Africa, Asia and Latin America and it is being produced at industrial scale in Europe, China and North America.

Normally plants decompose and return all of their carbon to the atmosphere, but when heated using high temperatures and low oxygen through a process called pyrolysis, up to half of the carbon is converted into highly stable carbon that can last for centuries when deposited in soils or other long-lived products such as concrete or asphalt. It can also help reduce methane from livestock farming, landfills and even the oil and gas industry. It can immobilize heavy metals and other toxins in soils. It can harvest excess nutrients in contaminated water bodies. And it can help farmers and cities to both adapt to and reduce the impact of climate change while supporting 12 of the UN SDGs.

Importantly biochar may be able to help countries increase their climate ambition and we are building a standardized framework for countries to quantify how much carbon could be sequestered based on available, unused biomass which includes livestock manure, crop residues, disaster, demolition and forestry debris and even sewage sludge.

Given the huge appetite for carbon removal credits and the extremely limited supply, biochar production is scaling quickly to meet current demand while bringing needed revenues to smallholder farmers and other producers.

But we need your help to get the word out, to build markets for biochar, to showcase current projects or future possibilities, to secure funding for scaling and to encourage countries to develop biochar based decarbonization plans.

I would love to hear what others would focus on if only given two minutes!

Dwelling on Drawdown Part II – C walls

Converting walls to carbon caches could be compelling when you consider just how much wall space there is in the average US home. Shifting from a high embodied carbon material such as drywall, to a carbon storing material could create a colossal carbon sink opportunity while also reducing current emissions from manufacturing materials such as drywall and making homes generally healthier at the same time.

The vast majority of inside walls in the US are covered using drywall (also called plaster board or wallboard), which is largely made from gypsum. The average American home, which is now close to 2,500 sf contains roughly 11,225sf of wall space.  A typical US home might therefore have 15,000+ lbs of drywall. The environmental impacts of mining, transporting and end of life for 15M tons of wallboard produced per year are enormous. Though it is recyclable, most of it heads to a landfill where it proceeds to off-gas sulfur dioxide, nitrous oxide (though this is also called laughing gas it is no laughing matter as it is a potent GHG), carbon monoxide and odors that you do not want to be smelling!

Covering walls with carbon storing materials is not new. Wood has long been used in many cultures, though it has fallen out of favor with many builders and homeowners. More recently we are seeing other carbon storage materials such as straw board or hemp begin to emerge.

One of the parameters for building my drawdown dwelling was to avoid drywall to the maximum extent possible and to utilize a variety of carbon storing materials instead. The exterior walls are built using straw bales – it took less than 2 acres roughly half a year to grow my walls – plus lumber of various flavors; dimensional, composite, etc. Interior walls (window sills and floors too) have been covered with rescued wood from barns and fences as well as locally and regionally harvested ash, cherry, maple and pine – a veritable forest or at least the ghosts thereof. All were sustainably harvested and putting them inside homes is a sure fired way to prevent the carbon absorbed during the tree’s lifetime from converting back into CO2 for as long as the house shall live!

As I am in the biochar world, I really wanted to have a biochar plaster wall similar to the one done at the Ithaka Institute headquarters in Switzerland. I procrastinated until all other interior walls were done which allowed me to get more comfortable with plastering in general. Now after two days of burnishing (i.e. rubbing walls gently with a mildly wet sponge to smooth lines, heal cracks and remove surface particles), the plaster is thankfully still on the wall and, all modesty aside, looks gorgeous (except for the tarps on the windows and the not completely finished window trim). Although originally I thought this was beyond my abilities, this is a project anyone can do but for those fastidious few, I warn you it is dirty to do (but pretty to view!).

Before taking the plunge, my co-conspirator and plaster master, Jill and I did some testing using different sized biochar, both of which came from Aries Clean Technology (Many Thanks Nancy at Aries!). Aries makes biochar from urban wood waste in Tennessee, and I knew they produce an IBI certified, very fine powdery size (2 – 300 microns) biochar that I’d wanted to test in plaster. They also had a chunkier size (<1/8”) which was worth exploring. Using the same recipe [50/30/20 v/v biochar, sand, clay] results in very different colors and textures which you can see in Figure 1.

Figure 1: On the left is the powdery biochar plaster which had a texture almost like frosting and on the right is much greyer and more like oatmeal.

The oatmeal version took quite a while longer to dry than the frosting.  In speaking with my colleague who pioneered this technique in Switzerland, he advised that the chunkier plaster can be used as a base coat to increase insulation and the finer biochar plaster makes a nice finish coat. Alas I already had a base coat, so decided to move along with the blacker finish coat. [For those that don’t fancy black walls, you can cover it using clay paint which comes in a variety of colors.]

We premeasured each ingredient and added them dry into a large bin before adding water. In hindsight, I would recommend wetting the biochar and/or clay beforehand to reduce dust while blending (kind of like slaking lime).  

We started with a 5 gallon bucket of Aries Green Tech powdery biochar, plus the requisite amount of sand and clay. We used roughly 3 gallons of water to get it into something just a bit heavier than frosting. This took quite a lot of time with a drill and paddle mixer to get to the right consistency and make sure everything was well blended. (If you are doing a bigger wall it would be easier to use a hydraulic mixer.)  I recommend doing this outside as there is a certain amount of splattering and in the beginning some of the particulate matter does get airborne. This ended up being not quite enough to cover a 80 – 90 square foot all, so we made up another smaller batch in a 5 gallon bucket.  

All in all, there is likely about 10 lbs of carbon (the Aries powdery char has 85% carbon) or about 36 lbs of CO2e; not a huge amount, but it was a very thin layer (1/8” – ¼”) and a pretty small wall!

Now let’s do some carbon math. Say this thin layer contains about .1 lb of carbon per sf (.367 lbs CO2e). That could easily be doubled or tripled as the average drywall width is 1/2″. Now imagine putting that on a majority of the 11,225sf of wall space in each home. Now multiply that by the nearly 1 million new homes built each year. That is big C storage opportunity with multiple side benefits. Those are the (C) walls we need to start building!

Side note: doing this type of project turns many a sponge and all clean up water very, very black. Knowing that the black comes from biochar means that tossing the black water out onto the soil or down the drain puts a guilt-free smile on my face knowing that it will enrich the soil and septic system!

2020 was not all doom, gloom & zoom for the US Biochar Industry

Good riddance 2020! Though I am not sad to see 2020 ride off into the history books, upon reflection there were a few highlights within the US Biochar Industry that should not go unacknowledged.  Here are a five worth celebrating as they may well help the biochar industry scale quickly in the year to come.

  1. An explosion of biochar related webinars! For many years I have hosted biochar webinars for the International Biochar Initiative to fill a void in biochar education. This year that void was filled to overflowing from many different organizations hosting a wide variety of biochar presentations, forums and continuing education credit opportunities. Most of these webinars or forums recorded the presentations which are now available for free. Several worth watching include:
  • The US Forest Service hosted a series of 8 webinars on a wide variety of topics including: what is it, production technologies, economics and several more. Mostly these were presented by US Forest Service employees that have been working with biochar for many years. (There were a few exceptions including one I gave on Innovative Products.)
  • The Scaling Biochar Forum, held in mid-October, was a 2 day event aimed at educating investors and philanthropists about the growing number of opportunities and funding needs within the biochar industry.
  • Cornell Cooperative Extension of Suffolk County hosted 4 webinars in November thanks to funding from SARE. Topics included: Biochar Basics, Science Behind Biochar, Ornamental Nursery Applications, and Landscape Applications of Biochar.
  • Thermochemical Conversion & Biochar workshop hosted virtually by the Rochester Institute of Technology was aimed at educating New York State policymakers, farmers, investors and more. The full recording is here and an overview of the event found here.
  • National Biochar Week – for 5 half days in December, biochar experts from around the country discussed many different applications and opportunities within the biochar industry. Recordings still being posted here.

2. First US producers receive carbon removal credits – the long awaited opportunity to tap into finance from the voluntary carbon markets arrived in 2020 for US biochar producers. Pacific Biochar was the first commercial biochar producer to profit from a collaboration with Carbon Future. Carbo Culture, a pre-commercial biochar producer also based in California has also been approved to sell carbon removal credits through Puro, the first carbon market to acknowledge biochar on a carbon marketplace.  Biochar credits are trading at significantly higher values than carbon offsets at least at this early stage. VERRA, a global leader in GHG reduction standards and methodologies, has also committed to developing and deploying a biochar GHG methodology in 2021.

3. USDA NRCS Soil Carbon Amendment Protocol (Code 808) – The USDA Natural Resource Conservation Service developed a protocol focused on increasing soil carbon specifically through the use of compost, biochar or a combination of the two. To date 20 States have adopted Code 808 and funding is apparently available up to $845 per acre for farms that have soil carbon issues. [Most of the information on this is only available in PDFs, so Google NRCS code 808 to find out more or visit your local County USDA to find out if your State is participating.]

4. Biochar allowed as a feed additive – but only in California so far! For years now the US Biochar industry has envied the European and other markets that have been able to sell high quality biochar as a livestock feed additive. Until quite recently that was not possible as the FDA had taken it off the approved list of feed amendments. In 2020 the California Department of Food & Agriculture approved the use of biochar (called charcoal in their regulations) in livestock feed. The Official California Code of Regulations for Food and Agriculture related to commercial feed states the following: (e) Charcoal (vegetable) is charred hard or soft wood, nut shells, or fruit pits. If it is wood charcoal, it shall bear a designation indicating whether it is hard wood charcoal or soft wood charcoal. Charcoal from nut shells or fruit pits shall be designated as shell charcoal. When used in a mixed feed the maximum percent shall be stated on the label. (Barclay’s Official California Code of Regulations)

5. Biochar Policy Task Force for the Biden Transition Team – As a majority of Americans (by at least 7M) breath a sigh of relief that the incoming administration understands, supports and ‘believes’ in science and climate change, the winds of policy change for the biochar industry began to formulate last month. The Biden Transition Team formed a bioenergy/biochar task force made up of a few biochar experts as well as policy wonks from many of the large US crop growers associations. They learned from various biochar academic and industry folk about the potential for US farmers and strategized about ways to help the industry scale quickly in 2021. Even just having this kind of dialogue signals a complete shift from the out-going administration.

One other anecdotal impact heard from various biochar industry players was that many folks around the world began to garden as a safe way to get out of the house and to feel more resilient. This created increased demand for the biochar industry in many parts of the world!

So, while 2020 seemed filled with doom, gloom and way too much Zoom, I hope you will agree that good things happened within the biochar world which laid a solid foundation for more to come in 2021.

Side note: I often use a picture of burned toast to describe the difference between torrefaction (regular toast) and pyrolysis (burned toast). It seems like a good visual to show why microbes prefer to leave it alone thereby allowing for long term sequestration versus decomposition.

From Wildcatter to Carbon Capper

Hopefully, for the sake of a livable planet, the days of wildcatting are nearly over. Prospectors drilling for oil and gas in regions not generally known to contain these materials came to be called wildcatters in the late 1800s. Prior to that a wildcat referred more generally to a risky venture. In retrospect wildcatters were gambling far more than their personal fortunes when they drilled hither and yon. Although to be fair, they could not have known that unearthing long dead plants to be burned as fuel could lead to catastrophic climate change.

What if there was a means of redemption for historical and current wildcatters? Perhaps those thousands or millions of wells, long since abandoned yet still able to wreak havoc below and above ground, could be converted into an ally in our urgent quest to rebalance atmospheric carbon. Perhaps wildcatters could become carbon cappers. Indulge me for a moment while I paint a picture perhaps with rose-colored glasses, and then feel free to join the conversation to figure out if this is even remotely possible, and if it is what is the potential for carbon sequestration, and how do we scale it in a time frame that makes a material difference.

Grist wrote an intriguing article earlier this month cheekily entitled Abandonment Issues. The gist of it is that carbon offset credits are beginning to be used to help finance the capping of old wells that are leaking methane, hydrogen sulfide and other toxins. Since many oil companies have declared bankruptcy to avoid covering clean-up costs, the bill is often left to taxpayers. Nowadays with Federal, State and Local government coffers severely depleted due to Covid, funding for this type of activity is challenging at best, even though it promises to provide needed jobs to unemployed oil & gas workers.

Non-producing wells seem to be categorized as abandoned, orphaned or idle. An estimated 3+ million of these wells in the US emitted 281 kilotons of CH4, a GHG far more potent than CO2. Currently a mere 50,000 are listed on State lists for clean up and even those will take years to properly close due to financial constraints. While a small minority may leak enough methane to cover the cost of capping the wells, the rest of the funds are currently being raised through donations or taxpayer dollars.

Typical materials used to cap wells include sand, gravel, native clay, sodium bentonite and cement (note: cement comes with a high carbon footprint which should be factored into the overall life cycle assessment for carbon offsets and removals). Now imagine if instead of sand or clay or cement, biochar could be used to displace some portion of these imported materials.

Apparently some of these wells, at least in my part of the world, are thousands of feet deep so could potentially sequester vast amounts of solid carbon in the form of biochar. While the volumes for filling smaller holes might not be large enough to raise sufficient carbon removal funds to cover the entire cost of capping, biochar could also be used to remediate nearby contaminated soil and water. It might also be better at sorbing hydrogen sulfine, benzene or other toxins than sand or clay.

One thing to note is that while revenues related to carbon offsets are still languishing at an average of $10/t of CO2e, carbon removal credits are currently garnering far higher prices. Though biochar has only recently debuted on 2 carbon removal marketplaces (Puro.earth and carbonfuture.earth), it is poised to become part of much larger marketplaces as VERRA, the world’s largest standards registry, just announced it is developing a biochar GHG methodology to be finalized by the end of 2021. Prices per ton of CO2e for biochar have ranged from $75 – 145 so far. Converting that back into dry tons of biochar generates $200 – $350 meaning the price of biochar could become cost competitive with other fill material if it is locally produced from waste material. To state that differently, for every ton of biochar used, between 2.5 – 3.0 tons of CO2e credits can be sold. (The multiplier depends on various things including emissions related to feedstock acquisition & transportation, processing emissions, carbon content within the biochar, etc.)

With insufficient experience in calculating the volume of materials needed for different sized wells as well as average land area needed to remediate, it is hard to calculate how much carbon removal revenues could be generated. But any additional revenues would no doubt be welcomed to plug these toxic legacy wells. I invite those that know far more than I do on this topic to discuss and hopefully demonstrate feasibility.

Dwelling on Drawdown Part II– Draining the Swamp

For the past several months I have been building my ‘Dwelling on Drawdown’ forever home. As the project name implies, a key emphasis is on sequestering carbon in as many ways as possible. So far biochar has not been the center of attention, but this week that changed as my septic system began to take shape.

First some background. On a freezing cold day last January when the civil engineer, accompanied by the local lake water quality control agent, performed a perc test to see how quickly water drains, the results were (unsurprisingly) not good. In my part of the world heavy clay soils are the norm. During the test, I (also unsurprisingly) waxed poetic about the potential benefits of adding biochar to the leach field – or drain field as it is also called. This was met with more than a little skepticism (and I suspect some eye rolling). However, much to his credit, when the civil engineer sent me the final design for the raised bed system, he outlined how biochar could be utilized effectively without raising regulatory concerns. Seemed like he may have read up on biochar after our little conversation!

Fast forward to the need to source sufficient amounts of biochar for draining the swamp, er… septic system.  What type of biochar is best? I don’t know if there is consensus on that as this might just be the first time it has been used in a residential drain field. There is no large-scale biochar production yet in Western New York and I’d already used up my own home-made supply in the water trench. I ended up ordering 6 super sacks from National Carbon Technologies (thanks to Cary Johnson!). NCT is probably one of the largest producers of ‘renewable carbon’ in the United States. Some of the carbon is used in carbon neutral markets but increasingly they are looking at carbon negative markets such as soil amendments. The biochar is made from sustainably sourced wood with high carbon content (>90%) and can be granular or pulverized – I chose granular.

Thankfully, the excavator (Schwartz Excavation) is a family friend and was game to try out the use of biochar. Eight truckloads of sand, mined about 20 miles away, were brought in to raise up the entire drain field. Next a trench was built for a distribution box to send out the effluent into 5 different trenches about 60’L x 2’W x2 1/3’D. The Civil Engineer advised digging deeper trenches and then first adding a layer of biochar to the subsoil. This meant that instead of digging only 2’ deep, trenches were 4” deeper to accommodate the biochar. Super sacks turned out to be the ideal packaging for adding biochar to trenches; it was no fuss, no muss and surprisingly little to no dust during the application. Randy, the excavator, declared that the biochar was too pretty to cover up after the first trench was filled. But cover it they did; first with 6” gravel, then they laid in the perforated pipe, 6” more gravel was added to cover the pipe, next a geotextile was used to cover the gravel to prevent soil from clogging the gravel and finally 12” of topsoil.

In total three super sacks were used or roughly 1 ton for the whole system. The carbon math on that means that nearly 3 tons of CO2e were sequestered in the drain field.

Why add biochar to a drain field? While I think most drain fields could benefit from biochar, living next to a lake makes reduction of excess nutrients and contaminants particularly important. Biochar will also likely help with water management. Given my druthers, I would have mixed the sand with significant amounts of biochar to reduce trucking, improve water management and boost soil fertility, but that will require more study and education of regulators. It might not be cost effective to do that at this stage, though with carbon removal credits beginning to evolve for biochar, that may soon change the economics significantly.

Wouldn’t it be something to design drain fields that are built to serve not only as filtration devices but could purposely be used as soil builders where enriched biochar is harvested every decade or two and used to rejuvenate or decontaminate poor soils and new biochar is added to start the process all over again? Hopefully some environmentally woke civil engineers are already hard at work on this!

Biochar in the time of Coronavirus

I have lost count of the number of people that have asked if or how biochar might be able to help when it comes to our current pandemic. Years ago I wrote about how biochar might be able to help prevent the spread of cholera, looking mostly at a post disaster scenario where this bacterial disease can often become commonplace. Containing a virus that has gone global is a totally different tragedy. Nevertheless, there are still ways that biochar may be able to help.

Masks made with biochar: Activated carbon has long been used in personal protective gear (PPE) and there is some indication that certain types of carbon may be effective in inactivated viruses (Matsushita et al 2013). Robert Tonks has pioneered a truly innovative, reusable mask (pictured above) that contains biochar which could be made in mobile manufacturing facilities. 

Carbonizing contaminated medical waste: At the moment, vast amounts of PPE are being used and discarded at an ever-increasing rate. Presumably much of this will be incinerated at least in those parts of the world where incineration is available. Carbonization might be a viable option however, at least for the paper-based PPE. The high heat temperatures should eliminate the virus and the resulting biochar could be used for a variety of purposes including potentially masks!

Carbonizing human feces: There is some indication that human feces may contain traces of the virus though more research is needed to understand if the virus can be spread from it.  To be on the safe side, putting sludge through a thermochemical conversion system would eliminate that risk – and provide substantial other benefits as well.

Carbonization vs. cremation: funeral homes are overloaded in hot spot zones for the pandemic. Though the concept of carbonizing human remains is still largely theoretical, it is feasible.  Keeping part of a loved-one’s carbon from returning to the atmosphere might seem like purgatory to some, but it might be one small way to help rebalance carbon levels!

Perhaps the most interesting take I’ve heard about how biochar can help during this pandemic has to do with stalled international deliveries of things like fertilizer.  Farmers in the Northern Hemisphere are just about ready to start planting and going without fertilizer is causing many to panic.  However, those that know how to convert biomass to biochar and blend it with locally available nutrients (e.g. manure, urine, compost, etc.) can wean themselves off their dependency on imported fertilizer. This not only increases their resiliency but also reduces costs and emissions related to fertilizer use It can also alleviate leaching of excess nutrients into local water bodies.

Sensitizing the sanitation community to sequestration (and biochar!)

I was recently asked by the NYC Department of Sanitation to keynote at their SOAR Strategic Partnership Breakfast which was also highlighting International Women’s Day. It was a great opportunity to enlighten urban sanitation folks about biochar. With a few edits, here is my talk (warning – longer than most of my blog posts but hopefully it will be of interest).

It’s been far too long since I roamed the streets of NYC as one who called it home, but the invitation to return and hear about what is going on in the world of waste, or as I prefer to call it, unloved organics, was more than a little appealing. When I last lived here my career was about as far away from reimaging or repurposing organics as it is possible to get. I did a mid-life career 180 after going back to complete a Masters in Sustainability about a decade ago. It was during that time that I read about a little something called biochar which changed the entire course of my life! At the time I had no idea how few people had ever heard of it, nor did I think that 10 years later, roughly 98% of anyone I’ve ever talked to about biochar would respond with ‘bio-what’. But over the last year or so, things have really started to change rapidly on so many different fronts within the industry, that I am convinced the future for biochar is bright. So if you had never heard of biochar before getting your invitation to this event, know that you are in the vast majority, but please allow me to enlighten you just a bit about this exciting and diverse material and the process by which it is made.

Biochar is a fancy new name for a material born from an ancient indigenous waste management practice – most likely devised by women in my humble opinion – since it centered around cooking. The process seems astonishingly simple in retrospect yet had profoundly positive and long-lasting impacts.  As you might imagine cooking in fire pits produces prodigious amounts of hot coals. It appears that human urine and probably other ‘leftovers’, were dumped on top of the burning coals in an effort to both reduce odors from urine and feces and to thoroughly quench the fires. Whether by accident or design this combination eventually converted crappy soils – that’s not the technical term but I grew up on a farm and that is how you usually hear low fertility soils described – into highly productive soils capable of feeding a population far greater than had been previously imagined. Fast forward a few millenia and those same soils are still up to 4x more fertile than surrounding soils in the Amazon which were untouched by human hands. In fact, those same soils are being dug up and sold to boost soil fertility elsewhere.

Late last century these highly fertile soils were re-discovered and piqued the interest of soil scientists and archeologists.  More recently the biochar industry has garned interest from a much more diverse flock such as waste managers, urban planners, the construction industry and climate change scientists and activists.  The reason for this diverse interest is that the production and use of biochar brings with it a range of benefits. Those of interest to this gathering include:

  • Volume reduction – depending on the temperatures used and the organic material volume can be reduced by 70 – 95%!
  • Speed – compared to other organic management practices, the use of high heat and low oxygen, what we refer to in the industry as thermo-chemical conversion or TCC can be done in minutes or hours versus weeks. Thermochemical conversion includes technologies such as pyrolysis and gasification, but it should not be confused with incineration. Think of it more like baking; you put something in the oven, close the door and crank up the heat. If you are anything like me, sometimes you get something that is not at all appetizing, but it is my favorite color – black! This unappealing taste may be why soil microbes and decomposers don’t like to consume it allowing carbon to persists in soils for millennia.
  • Odor & pathogen control – TCC can also significantly reduce and in many cases eliminate odors and pathogens both directly and indirectly – meaning when added to landfills, compost piles or manure slurries, it can bind or hug toxins to prevent them from leaching and do the same with ammonia which causes the all too-familiar smell of ‘eau de landfill’.
  • Scalability – technologies for converting organics to biochar range from backyard kilns capable of carbonizing tree debris, to community scale, to multi-million dollar production facilities.
  • Renewable energy – some TCC technologies can harvest the heat generated from baking the organic matter. This heat can either be used for drying wetter material or can be used for other heating needs.  Other equipment produces syngas which can be used to generate electricity while still others produce bio-oil which can be refined to be used as a fuel.
  • And finally, there is the carbon impact. Organics sent to landfills or even to compost facilities can emit significant GHGs. While carbonizing organics with high heat and low oxygen does produce some GHGs, when managed properly TCC is considered a negative emission technology (or NET), meaning the overall impact is that more carbon will be prevented from returning to the atmosphere than is emitted. Think of it as carbon interruptus.  This is something the IPCC and others have said is critical to avoiding climate chaos.

We are seeing more requirements to reduce and neutralize emissions at least in NY, if not at a national level. Given that, shifting from a carbon belching process to a carbon banking one, may be well worth considering.  And though the carbon markets in the US don’t yet recognize biochar production and use as a product category, that is one of the areas that is starting to change very quickly. I predict we will start to see increasing revenues focused on carbon removal (e.g. NETs) versus carbon reductions (i.e. from renewable energy generation). Biochar is likely to be a key component of carbon removal markets.

A growing number of closed loop biochar production scenarios are sprouting up across the globe. Here are just a smattering.

  • One of the oldest can be found in Austria where a compost company, Sonnenerde, began accepting paper mill waste and turning it into biochar which was then blended with different compost recipes.  Adding biochar to compost can not only reduce odors and pathogens as I mentioned, but it can boost temperatures, speed up the processing time, hold on to more nutrients, serve as a bulking agent and provide longer lasting carbon to the soil.
  • One of the most talked about models hails from Stockholm where the city converts green waste from residents and city Parks into heat that is fed into a district heating system and biochar.  Their first demo plant was launched as a way to reduce the amount of biochar they imported from other countries which they had been using to improve urban tree survival.  An unanticipated benefit they discovered as they began to use more and more structured soil made up of gravel, compost & biochar is that the amount of rainwater that could be stored during storms increased significantly while the amount of toxins from roads and roofs that had to be dealt with at the waste water treatment plant decreased. These toxins were bound in the biochar. City officials took notice and now this model is being replicated not only across Sweden and Europe, but here in the US as well where I believe Minneapolis is the first large city to be planning a pyrolysis plant.
  • More recently an Australian company, Rainbow Bee Eater, located a carbonizer in an enormous 2 acre greenhouse to provide renewable energy. The fuel for the carbonizer is wood supplied by a local composter who provides it for free in exchange for taking the biochar produced from the machine which is added back to their compost.
  • Closer to home is an enormous gasification plant being built in New Jersey by Aries Clean Energy. They plan to convert 440 tons per day of sewage sludge into 22 tons per day of char. A long-term offtake agreement has been signed with a local cement company that will be using it as a filler instead of fly-ash, a by-product from coal fired electricity generation plants. In the past decade alone roughly half of the coal generating capacity has been shuttered so cement manufacturers are on the look-out for new alternatives.  
  • East of here, out on Long Island, 2 projects are being investigated aimed at carbonizing mountains of wood chips which are leaching heavy metals into the groundwater.  The goal for at least some of the biochar to be produced is to use it in bio-filters across the island to reduce the amount of nutrients, phosphorus mostly, leaching from hundreds of thousands of septic systems into local water bodies causing massive algae blooms and die off of various native aquatic species.
  • And in Western NY where I live Cornell University in collaboration with NYSERDA is looking at siting the first pyrolysis plant on a dairy farm to deal with excess manure. Amongst other end uses for dairy manure biochar, we will be looking to use it to filter the wastewater from dairy production or possibly the effluents from nearby food processing companies such as yogurt or tofu manufacturing. Using biochar in this way harvests the nutrients and allows them to be cycled back into the soil for use by plants. We dubbed this kind of beneficial carbon cascade the ‘filtration to fertilizer’ approach
  • I’ve also been working with the Rochester Institute of Technology for the past several years on converting different types of food waste into biochar. Biochar made from mixed food waste may have a lot of salt or chlorine, so using it in soils may not be the best solution. Instead we’ve been looking at using it in different types of composites. I have a prototype here which is a non-plastic, compostable tray made using 20% coffee waste biochar. One could call it biodegradable but I don’t love the term biodegradable due to the negative connotations of the word ‘degrade’. Instead I prefer bioUPgradable, since biochar-based products will sequester carbon and not produce GHG emissions whether you compost it or toss it in the landfill.

Low or variable quality biochar from mixed food waste or sewage sludge is also being tested in asphalt while higher quality and more consistent biochar is starting to be used in building materials such as flooring, composite lumber, and exterior siding. This will hopefully encourage the construction industry to build vast new above-ground carbon sinks.


There are a growing number of ways biochar can help New York achieve some of the ambitious legislation that has been passed in the past year or so.  The Organics Mandate prohibiting large scale food waste from being sent to landfills is one example.  Providing additional ways to deal with food waste such as TCC, could support broader adoption.  Co-locating pyrolysis with composting operations or anaerobic digesters may make a lot of sense.

I’ve mentioned the boost to compost that adding biochar can make but there are also synergies with anaerobic digestion as well. One issue some AD operators have is managing the excess fiber or digestate.  Digestate can be used as a feedstock for biochar and help reduce volumes.  The resulting digestate biochar can be fed into the digester as a carbon source. Research has shown that this can improve the quantity and quality of methane produced making the economics of operating a biogas plant more attractive. Biochar also seems to provide a kind of buffer which helps smooths out production ups and downs which occur when the substrate mix is changed. Adding biochar can also reduce the amount of hydrogen sulfide produced which can be harsh on equipment, reducing its operating life.

Biochar can help New York achieve the aggressive yet vital goals that were set forth last year in the Climate Leadership and Community Protection Act.  That legislation committed NY to a goal of 85% reduction by 2050 with all sectors being net zero emissions by then as well. To reach net zero, those that cannot completely eliminate all emissions must offset any remaining emissions through projects that permanently remove GHG from the atmosphere. What is new and I think important that NY has done with this legislation is that they will not allow renewable energy to be used as an offset as that is already baked into the reduction goals.  There are not that many ways to permanently remove GHGs from the atmosphere. Trees can do an excellent job pulling CO2 from the atmosphere, but as we’ve seen out West and Down Under, those trees are increasingly at risk of going up in smoke and giving back all the CO2 they absorbed during their lifetime.

According to the IPCC biochar is one of only 6 technologies touted as being able to make a material difference in rebalancing atmospheric carbon levels. Half of the other suggested technologies have yet to be proven economical viable or environmentally benign. In comparison biochar production and use is safe, scalable and shovel ready. It provides multiple benefits above and beyond the ability to help mitigate and adapt to climate change as I’ve already described.  

So with all this good news, why haven’t more people heard of biochar and why haven’t more communities adopted this kind of waste management approach? That is a question I get asked A LOT. In fact, I ask myself this question all the time.

A few years ago, the lack of biochar adoption could have been blamed on the lack of sufficient time-tested equipment or, importantly, local technical support available to make a good quality, consistent biochar. That has begun to change.   

One of the reasons I believe biochar has so far struggled is that the primary market targeted over the past decade has been agriculture. In the early days of any new industry when production is low and prices are high, going after a market that is already very low margin and high risk is probably not the best first step. Until or unless farmers start getting paid to build soil carbon their focus must, of necessity, be on the lowest cost means of production and right now biochar is too expensive for many annual crops when you compare it to cheap chemical fertilizers

Over the past few years though the industry has begun to expand their market focus beyond soil applications. Nowadays we are looking at less seasonal and more repeatable markets such as filtration where it can compete cost effectively against activated carbon, or in plastics and other composites where it can displace carbon black, a high cost fossil fuel product used in everything from back plastic bags to tires. It’s even finding its way into batteries. Those higher value markets will enable production to scale which will enable prices to fall which will hopefully then make it more economically feasible for most farmers to use it.

As with every young industry, we have seen companies enter and fold, we have had our fair share of snake oil salesmen and those hoping to quickly cash in on a perceived gold-rush – mind you many of those are the ones that have already departed, thankfully. Right now we are seeing an unprecedented level of interest from impact investors, carbon brokers, communities choking on waste, foresters desperate to remove excess biomass and of course many who are beginning to panic when it comes to climate change.

We are thrilled at all the new interest but those of us that have been in the industry for years understand and want to make sure that others understand that biochar is not a silver bullet nor is it like the Field of Dreams where you can expect to have unlimited demand once you start making biochar. To make the economics work and to maximize the carbon impact, it is critical to create biochar production scenarios that embrace the circular economy, that utilize all possible co-products including heat, and to build local markets instead of shipping biochar half way around the world – something which is happening far too frequently. Waste managers are uniquely poised to help build this industry but my advice would be to partner with someone that knows biochar well before you dive it. There are as many different kinds of biochar as there are different kinds of biomass; more really since different production parameters generate different qualities in biochar. Each of these types of biochar may be good for different markets and therefore the expected price for it will differ.

With that said, I welcome each and everyone of you to learn more about biochar. We need to scale this industry quickly and efficiently. 

If you are interested in learning more about biochar, the Rochester Institute of Technology will be hosting a free one-day thermo-chemical conversion and biochar workshop on April 20th up in Rochester. All are invited though registration is limited and required.

I also need to give a shameless plug for a book I co-authored last year called BURN: Using Fire to Cool the Earth.  In this book we explore many of the markets I’ve mentioned today and more. 

Many thanks for listening (well reading in this case!) and Charpe Diem!