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The Celo Blog

Celo to go Carbon Neutral with Project Wren

Supporting a blockchain that’s good for people & the planet

UPDATE 4/20/22: Since this post was first published, the Celo community has come a long way in its efforts to build a carbon-negative blockchain that supports the planet and all who live on it. In May 2021, we shared several exciting climate efforts that were then on the horizon. Later in the year, the Celo community launched the Climate Collective, a strong and growing coalition of companies building at the intersection of Web3 and climate action. Since then, we’ve published research about how Celo and the Climate Collective can help scale the voluntary carbon Market, and most recently announced a deep collaboration with Toucan Protocol to accelerate regenerative applications using Celo’s carbon-negative blockchain and mobile-first infrastructure.

Celo is now a leader of the regenerative finance (ReFi) movement, helping to create the profound systemic change needed to not just reverse the climate crisis and restore the health of the planet, but also greatly improve the health of our communities and empower individuals.


We’re helping make Celo carbon neutral! As a member of the Celo Alliance for Prosperity, Project Wren is excited to follow-through on our commitment to further Celo’s mission of prosperity for all — starting with our planet.

Celo is an open platform that makes financial tools accessible to anyone with a mobile phone. By integrating with the Celo technology, we have the opportunity to positively impact 5.6B+ smartphone owners around the world. Celo is supported by a mission-aligned network of technologists, international NGOs, and organizations committed to building an inclusive, better financial system — including Wren!

Why integrate with Celo?

Blockchain technology provides amazing opportunities for financial innovation however it’s known for high energy usage and consequently massive carbon footprint. While this is still true for Bitcoin, more recent blockchains have evolved to a new consensus mechanism (Proof of Stake) that uses significantly less energy. Celo, a mobile-first blockchain platform that makes financial tools accessible to anyone with a mobile phone, is a Proof of Stake network, thus making it more earth friendly. However the Celo community felt they could do better and have decided to become one of the first carbon neutral blockchains.

“For any technology to thrive, it cannot depend on limited resources. The future of human progress will require that we prosper with our planet, not at the expense of it. This is why the Celo community intends to be carbon neutral.” — Amy Slawson, Partner, Engineering at cLabs

That’s why we’re excited to work with the Celo Foundation to offset the carbon emissions of their blockchain. Since blockchains are decentralized and anyone can be running part of the Celo network, it would be impossible to enforce the blockchain to run only on renewable energy. So, as their blockchain increases demand for electricity and causes more fossil fuel to burn, the Celo platform will contribute to our community tree planting project to remove the emitted carbon from the air and make the blockchain carbon neutral.

How it works

Decentralized systems typically incentivize participants to maintain the network through rewards in the form of crypto assets. For example, successful mining of a block may earn a miner a Bitcoin. Similarly at the end of every epoch (initialized to one day), Celo distributes Celo Gold (cGLD) to various network participants and funds, including the Carbon Offset Fund. The fraction of the rewards is based on the projected carbon emissions of the network, the estimated average value of the epoch rewards, and the offset project costs.

Looking forward

We will not be able to decarbonize the economy overnight, and we have to accept that some important changes to the world will increase humanity’s carbon footprint for now. Carbon offsets extend the runway we have before hitting catastrophic climate change. While offsetting isn’t a long term solution, it is the fastest option for most of the economy while we bring way more renewables online. Offsets enable companies to pay for the negative impacts their carbon footprint has on the rest of the world.

We hope to see more companies follow the Celo Foundation’s example and “opt in” to a carbon tax, and look forward to working closely with the team to see how we can help organizations make sure their operations allow for a climate where all humans may prosper.

Update May 18 2021:

Within its first year of operation, the Celo platform offset 2219.5 tons of CO2 through Project Wren. That’s like walking instead of driving for 5,000,000 miles. You can follow the network’s latests stats here.




Celo is a carbon-negative, L1 protocol with a rich ecosystem of global partners building Web3, mobile-first applications to create a more accessible and inclusive global financial system. Visit to learn more about the Celo community, contributors, and technology.

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