SCF #11

Stellarcarbon provides transparent nature-based carbon offsetting with proof of retirement on Stellar and in the Verra Registry.

Budget request:

Project Stage



Micro & B2B Payments

Based in

Australia & Netherlands

Team size


Active since

Xpollinate was registered in 2018 and Stellarcarbon registered as a trading name in 2021.
Products & Services

With Stellarcarbon, anyone with a Stellar account can do a voluntary carbon offset that is registered both on-chain and off-chain. We have been building the infrastructure needed to connect legacy carbon markets with the new digital economy taking place on public ledgers. Other companies building on Stellar will be able to integrate our backend service into their products and services, to give users easy access to carbon offsets. On top of this infrastructure, Stellarcarbon itself wants to develop and launch a retail shop for carbon offsetting aimed at individuals and businesses.

What We Do Better

A major problem that voluntary carbon markets have faced over the past decades is low trustworthiness, on both the supply and demand side. While several governance bodies have stepped up to increase the integrity of carbon markets, it is still possible for providers to offer carbon credits without any oversight. Stellarcarbon addresses this problem by only working with a subset of VCS and CCB certified offsets, and by individually vetting projects.

Centralized registries are still essential, and we need to rely on them for the safeguards they provide. Unfortunately, they offer no way to intervene when an offset is used to make inaccurate claims about a company’s sustainability, or is even used to cover up environmental or social damage caused elsewhere. Stellarcarbon will develop terms of purchase that, together with a clawback mechanism, will allow us to invalidate malicious offsets on-chain.

Stellar provides us with the payment rails to fund offsets, and with transparent accounts onto which we can lock a carbon offset. An offsetter can pay with any liquid asset in their account to receive CARBON, select a vetted offset project to fund, and receive CarbonSINK as on-chain proof of retirement. Their offset is recorded in the Verra Registry, and the offsetter receives an off-chain certificate directly from Verra.

No items found.
Previous Project(s)
SCF #9
Award recipient
Sinking carbon with Stellar
Learn more
Progress so far

Since our participation in SCF#9 we have taken the time to focus on our core proposition. The prototype we showed a year ago still involved many manual steps, which we’ve had to automate to improve the scalability of our operations.

We have purchased a larger supply of VCUs and minted 176 CARBON in several blocks on February 1st.

Most of the progress was made on our API:

  • The API has been deployed on a production server
  • The API now provides XDR for sinking transactions that are signed by Stellarcarbon
  • Implemented a pricing curve that takes into account variable VCU procurement prices
  • Offsets are now funded with CARBON if the account holds a sufficient amount, and only with a path payment if it doesn’t
  • We’re now alerted by email of pending transactions and low pool balances
  • Added a “get quote” endpoint for offsets funded by path payments
  • Started implementing fractional on-chain offsets
  • Expanded API endpoint documentation

During the SCF#11 bootcamp facilitated by DFS Lab, we were able to make rapid progress on a retail-oriented offset shop. The bootcamp process allowed us to critically look at our proposition with fresh eyes and encouraged us to learn from existing solutions. At the end we delivered a prototype that lets users sign the transactions prepared by our API with the Stellar wallet that they are already using. Several testers have provided us with feedback that we are currently implementing in the next iteration of this prototype web app.

  1. Automated end-to-end retirements from sinking transaction to Verra certificate
  2. A retail-oriented user interface that can be used with multiple Stellar wallets
  3. Several subscribers as well as new customers that fund irregular offsets
  4. Retired 100 VCUs by the third month after our public launch
  5. Created a CARBON/USDC liquidity pool in a compliant way
  6. Identified at least two additional verified carbon projects to source VCUs from
To get there, we request a budget of  
  • Develop a listener for on-chain sinking transactions which finalizes the retirement in the Verra Registry
  • Develop a UI that uses WalletConnect v2 and/or Simple Signer to connect to wallets
  • Support SEP-8 (Regulated Assets) in the API for enhanced interoperability
  • Open-source monitoring and “continuous auditing” tools to verify that the on-chain state of assets issued by Stellarcarbon at all times matches the state of our accounts in the Verra Registry
  • Contact offset project developers about payment in stablecoins
  • Go through another round of legal consultation
  • Recruit a part-time frontend developer, or freelance equivalent
Additional information


Using the Stellar network, assist to draw down carbon dioxide in the atmosphere to 350 ppm while; educating about the need to reduce emissions (#SustainableWithStellar), and improving the integrity and visibility of the offset process using distributed ledger technology. By increasing the accessibility of voluntary carbon credits we believe normal people can take a more active role in shaping a safer climate for our planet's future and appreciate the sustainability of the Stellar platform.


Stellarcarbon will provide a simple way to:

  • Support carbon offset projects
  • Provide proof of accredited projects
  • Retire accredited carbon offsets
  • Claim an offset on the Stellar ledger
  • Vote on future carbon offset projects for Stellarcarbon to support
  • Penalize bad actors

Supporting an offset project through Stellarcarbon

To claim a Greenhouse Gas (GHG) emissions offset or “credit retirement”, CARBON credits in a user’s Stellar account need to be swapped for a token that represents the retired balance, in a way that also prevents retired credits from being transferred or traded. This is simply done by incorporating the swap into a single transaction, i.e., the amount of CARBON that the user would like to claim as an offset is returned to the issuer, and the user’s account is credited with an equivalent amount of CarbonSINK.

Within this transaction the user is first granted authorization for the CarbonSINK trustline, and at the end of the transaction this authorization is revoked, effectively locking the balance on their account. This mechanism is designed to allow a Stellarcarbon administrator to move a user’s entire CarbonSINK balance to another account, if the need arises.

On the Stellarcarbon backend, this offset transaction will subsequently be added to the Verra Registry, referencing the Stellar transaction that was initiated by the user. Initially this involves a manual step because Verra does not currently expose an API. This forces us to require a minimum CARBON balance to retire, as we cannot manually engage with trivially small amounts. Stellarcarbon aims to fully automate this process in order to allow offsetting small amounts, as well as reducing the latency before proof of retirement is visible in the Verra Registry.

Target market

Buyers of carbon offsets (people, communities, companies) want a simple way to calculate and offset their carbon emissions by supporting credible offset projects. Producers of carbon offsets, as well as Stellarcarbon and its prospective partners, want their reputation protected from bad actors, and to have a simple way to prove the integrity of their offset credits and to expand their offering.

Incentives from an end-user perspective; “buying and retiring carbon offsets allows me to”:

  1. Clear my conscience (applies to individuals & communities)
  2. Boast about my support of carbon offset projects (i.e. social credit, the prime concern of corporations and other organizations)
  3. Contribute to the common goal of conserving established forests and restoring damaged ecosystems, to help reduce GHGs in the atmosphere to sustainable levels
  4. Build up a CarbonSINK balance, which may provide access to gated services and discounts with Stellarcarbon partners
  5. Buy, store, and save carbon tokens to actively take part in shaping the future of our planet.

Revenue model

Xpollinate is currently financing the project. We place a margin on the purchased offset credits to help cover costs including development, and to provide cashflow for purchasing more offsets. This will be scaled by partnering with other businesses already using Stellar with existing client bases and incentivizing them with a small margin to encourage them and their clients to offset their emissions.

Relevance to Stellar

Replace legacy payment rails and intermediaries to reduce fees and costs. We’ll investigate how much of the existing offset project financing rails can be replaced by usage of stablecoins on Stellar.

Threats and opportunities

Strengths - The team has experience with the Stellar network, other Stellar projects and infrastructure, as well as with integrating Stellar into third party solutions.

Opportunities - Attract more team members to contribute and partners who are already developing on Stellar.

Threats - Need to grow to a large turnover to become financially sustainable.


There are several recent initiatives that are similar to ours on other distributed ledgers. Most notably there is the Toucan Protocol which runs on the Polygon Chain. Toucan has chosen to “cancel” VCUs on Verra before they can be bridged. This mechanism has since been banned by Verra, preventing Toucan to bridge any more VCUs until a solution is found.

Marketing and sales

Once we have a pilot and a sufficiently automated offsetting service we want to be able to see how things will grow organically. This will give us some confidence to pitch to others developing on Stellar to offer them an integration solution to offer our services to their clients.

Pitch deck
No items found.
First Deliverable

Stellarcarbon is a business trading name of Xpollinate Pty Ltd, a business management consultancy that “Cross Pollinates” ideas and businesses to deliver innovative solutions.


Adam Menary (xpollinate#0648)

Stellarcarbon Co-Founder & Director

Adam has a Bachelor of Agricultural Science with Hons. Adam has 30 years of experience in supply chain management and has developed an assortment of related technology solutions.  Adam undertook the first ISO31000 supply chain studies for Beef and Dairy from Australia to the USA, which was tabled as the basis for a bilateral trade agreement under the Bioterrorism Act. Adam has overseen the integration of blockchain technologies into existing commercial products.  He is passionate about real action on climate change and a co-founder of Beyond Zero Emissions, which has become one of Australia's leading think tanks on climate action. Adam believes that the future salvation of the planet lies in decentralized finance and transparency, and he has supported Public Node as well as invested in the Stellar Network, and more recently actively participated in AQUA liquidity pools and automated market making. Stellarcarbon aims to provide a global solution to facilitate education and real climate action by individuals.

Current roles:

  • CEO of Enrolo, a Registered Training organisation and provider of a SaaS learning management system
  • Founder of Blockchainifier an end to end supply chain consultancy integrating blockchain into supply chains
  • Patron of the Great Forest National Park: a proposal to create a National Park around the city of Melbourne to protect biodiversity and  carbon.

Previous roles:

  • Co-Founder of Beyond Zero Emissions an Independent solutions focused think tank that conducts and publishes research on solutions that unlock economic potential for industries, regions and communities.
  • Chief Technical Officer for Icon Global Link a risk management solutions provider.

LinkedIn: adammenary

Twitter: @AdamMenary

Keybase: @Xpollinate

Reddit: u/xpollinate

Daniel Fisher (magofox#8341)

Stellarcarbon Co-Founder & Advisor

Daniel is the co-founder of Public Node, Stellarmint, and Lumenthropy. Outside of his work within the Stellar ecosystem, he has been an energy economist for over 15 years.

Alex Olieman (convergence#6459)

Stellarcarbon Co-Founder & Lead Engineer

Alex works as a research programmer at the Institute for Logic, Language, and Computation at the University of Amsterdam. His research focuses on the application of information extraction, specifically entity linking, to improve the accessibility of information and data. Alex is interested in working with large open datasets, and has done much of his work with government archives. In addition to his research work, for the past 8 years he has helped Qollab grow from a 4-person team into a mature product that was recently acquired. He also is an avid open source software contributor, and has been an active participant in the DBpedia community.

Since 2020, Alex has become more active in the Stellar community because he got absolutely hooked on Stellar Quest. He had already been participating in discussions on Keybase for several years, has served as a voter and later as a panelist in previous SCF rounds, became a Public Node member, and has attended Meridian twice, but earning all Stellar Quest badges delivered the final shove for him to start building on Stellar. Alex is a generalist with a background in Industrial Design Engineering, a Bachelor of Science in Future Planet Studies, and a Master of Science in Information Studies. Several of Alex’ long-term interests have come together in Stellarcarbon, and he is very much looking forward to spending more time on its further development.

LinkedIn: alexolieman

Google Scholar: Alex Olieman

GitHub: aolieman

Keybase: @alioli

Oli Torfason (Oli Mojoflower#8074)

Stellarcarbon Advisor

Oli is co-founder and CEO of Mojoflower ehf. Mojoflower is building an asset issuance and registry for SMEs. The Mojoflower project is a former recipient of the Stellar Seed fund. Oli is also a board member of the Icelandic blockchain foundation. Oli is passionate about geothermal and sustainability and in Iceland there are currently a number of very inspiring projects that are focusing on carbon and sustainability.

Twitter: @mr_mojoflower

Keybase: @mojoflower