Let's do something with enhanced weathering
In our endeavor to enable negative emissions one of our next goals is to set up olivine based pilot projects for enhanced weathering together with our partner company Fieldcode.
This blog article explains WHY we do this and WHAT questions we need to find answers for.
Motivation and Reasoning
Life on earth and human civilization are at risk due to climate change. Although the details are rather complex there is in fact a simple linear relationship between the CO₂ content of the atmosphere and the global temperature. Doubling the CO₂ levels will make earth 2.9°-4.3°C warmer. We have already added 48% since the 1850s, which gives us 1.25°C warming, and we are currently adding another ~1% (=one percentage point) each year.
This linear relationship forces us to think about three brutal facts:
It will continue to get warmer as long as we add even the tiniest bit of CO₂ to the atmosphere (just stopping emissions is not enough)
Since there are various processes that we can’t fully decarbonize everything we need some kind of negative emissions to mitigate these hard-to-avoid emissions (otherwise we will never reach zero)
When we reach zero emissions it will not get cooler unless we actively suck CO₂ out of the air.
In essence we believe that in 20-30 years humans will need a massive industry that sucks CO₂ out of the atmosphere at epic scale. Current annual emissions are ca. 50 gigatons of CO₂ equivalents (includes the effects of CH₄ and N₂O). Gigatons are 1000 x 1000 x 1000 tons, a hard to comprehend scale. In 2050 this industry will need to be 3-4 times as big as the current global oil industry.
We need to get going
It will obviously require the cooperation of most humans, countries and organizations to reach the massive scale that is needed, and speed is crucial. Unfortunately there is still very little activity going into negative emissions (except academia), mostly because most people don’t realize that this will also become a business opportunity which will at least pay for itself which will drive this technology forward. With more and more organizations and countries announcing plans to reach carbon neutrality in 10-50 years there will be a massive demand for negative emissions because without them zero-CO₂ is impossible. This, together with policy changes, will make a carbon price of €100 per removed ton of CO₂ possible in 10-20 (?) years.
We will do something now
Our goal is to find an approach that
will theoretically be able to remove at least 400 megatons of CO₂ per year by 2040 (1% of global emissions, this does not imply that WE alone will be the people doing this)
will cost < €100 per ton of CO₂ by 2030
is permanent (secure storage >90% for >100 years, preferably much longer)
does not involve massive custom-designed/built machinery
has acceptable socio-economic and environmental impacts
executes at least 50% of its lifetime removal potential in 5 years or less
Why we will go for enhanced weathering
Enhanced weathering is the accelerated version of the natural geological process that collects CO₂ from the air by reacting it with minerals. And it checks all the boxes of our requirements:
Minerals like olivine react spontaneously with CO₂ from the air in an exothermic reaction which creates stable carbonates that last for millenia.
There is far more olivine available to us than we will ever need to remove all accumulated unwanted CO₂ from the air.
Mining one ton of olivine costs between €10 and €30, processing costs a few €, emissions from mining and grinding are negligible in a lifetime CO₂ assessment, and even transport emissions are no problem if we don’t ship/drive the stuff around the world.
All necessary mining technology is already developed and commercially available.
With proper grain size and reaction-environment 5 years to reach 50% potential may be feasible.
With enhanced weathering humans would be able to mitigate all current annual CO₂ emissions (40 Gt) at a cost of 400-1.200 billion euros, 0,4%-1,2% of global GDP. That’s not impossible.
It is obvious that geology must be a part of the solution
Humans have created this problem by using technology (oil drills) to pump carbon from the ground into the atmosphere. Solving this problem will also require us to use technology to move the carbon back into geology (we don’t have any other use for it at the necessary scale). The superfluous CO₂ in the air is effectively useless and dangerous waste and we must pay for dumping it off properly.
Many other carbon removal options do not meet our stated requirements. E.g. trees, algae or biochar are not permanent enough or don’t scale far enough and fast enough, others are (still) too expensive.
Science says it works - But nobody actually does it
Until 2017 there were already >2500 studies about enhanced weathering and their conclusions are all similar: It works, but further studies and actual field experiments are necessary. As far as we know for dedicated carbon removal projects there are no larger pilot projects beyond 1x1 m² test-plots (except for Project Vesta, which we already support).
Here are some facts from selected studies:
1 ton of olivine can remove 0,5-1,5t of CO₂ (Schuiling 2013)
Reactivity (speed of removal) is faster the smaller the ground particles are (Summers 2005)
In ground/humus the CO₂ concentration is up to 100 times higher than in the air (Schachtleben 1982)
To grind olivine you don’t need more than 100 kWh of energy per ton of olivine (Summers 2005)
The more acidic the surrounding the faster the reaction (Oelkers 2018)
All anthropogenic CO₂ can easily be compensated with olivine (Renforth 2012)
Mine tailings spontaneously and autonomously remove CO₂ just by being there (Wilson 2009)
Practically no Cr and Ni emissions found for 2.000 tons of olivine on one hectare (Renforth 2015)
With particle size of 1µm they found removal of 200 tons of CO₂ per km² in 1-5 years (Renforth 2015)
What do we do?
There is a lot you can do with olivine - What is our choice? Our goal is to actually do practical work with olivine as soon as possible. We clearly don‘t want to start a „concept study“ for 2 years („academic approach“), and then start with the rocks afterwards. Of course there are a few questions that need to be answered before we can drive around with a truck. This happens in Phase 1 (2020). The questions are (incomplete list, to be extended!):
Where can we start a pilot project?
What are the legal requirements we need to comply with?
Physical: What tests and/or pilot projects will we do? What equipment and manpower will we need? DIY, or shall we onboard a science team/university for that?
Measurements: How do we measure the removal when we perform real world tests?
Logistics: Where do we get our olivine from and how?
Legal: May we cross borders, may we throw it on the ground and into the sea?
Our goal is actually to “work with stones” in Phase 2 (starting early 2021, preferably somewhere in the range of 50-500 tons?): Here our goal is to learn and understand the various options. The questions that we need to answer to are:
Which of the enhanced weathering mechanisms that are available to us has what physical, economic, and socio-economic effects?
Do we need beaches, rivers and/or the ocean floor (movement/crushing of grains)?
Or can we do this on land?
Can we use unused wastelands?
Or are farmed soils much better (side effect olivine as fertilizer) and more accessible?
How small must we grind for acceptable speed? Will it be blown away by the wind?
How long will it take to achieve 10%, 30%, 50% of the stone‘s CO₂ removal potential?
Then there are some practical questions:
Financial: How much money do we need over the next 2 years?
Public relations: Regardless of WHERE we do something, we will need acceptance from the government, city/county council, and our neighbors. How do we get their buy-in?
Knowledge: Who are the most knowledgeable people about these topics, can we get them to join/help us?
Science: How can we make our findings public in a trustworthy way so the results can be replicated by others (to achieve more scale)?
In Phase 3 (2022) we will apply what we have learnt and try to scale it into a pilot project that removes a few hundred or thousands of tons of CO₂. Followed by phase 4 (2023+) where we… well… we have no idea yet.
This is our understanding as of now, we do have some answers (or at least a hunch) for the questions above, but there is still a lot to figure out. Our understanding will change as soon as we have new knowledge…
If you’d like to help or if you have feedback we would like to hear from you. Please write to info@carbon-drawdown.de or contact us on Twitter @carbon_drawdown.