Back
Methods
Descriptions of our metrics and notes on each carbon removal project we have analyzed. For more on this work read our articles on what we learned analyzing proposals submitted to Stripe in 2020 , Microsoft in 2021, or Stripe in 2021. If you have questions or want to get in touch. check out the feedback section.
Sources
Metrics

Sources

We develop this database by analyzing public proposals for carbon dioxide removal.

Thus far, we have obtained proposals from calls for carbon dioxide removal procurement, e.g. from corporations looking to purchase carbon removal. In principle we could obtain proposals from other sources (e.g. directly from projects or public processes), and we may explore this in the future. Repeated proposals from the same applicant are listed and analyzed separately.

While all proposals in this database claim to offer carbon removal, we do our best to surface the mechanisms underlying the proposal. Some projects exclusively perform carbon removal. Some include a component of avoided emissions. Some are exclusively avoided emissions at the moment, but could be part of a carbon removal system in the future. (Read our explainer for more on the difference between removal and avoided emissions).

Our analysis is based exclusively on public materials, including project proposals, public websites, registry listings, published literature, etc. In some cases we obtain early access to public proposals to get an early start on our analysis and make our reports as timely as possible. In cases where projects provided confidential information to prospective buyers alongside their public proposals, we avoid exposure to confidential information to the best of our ability, and do not incorporate it into our reports.

Below is a brief overview of our current primary sources.

Stripe 2021

In sprint 2021, Stripe ran a new round of carbon removal purchases. CarbonPlan collaborated with Stripe to design a new, open source carbon removal application. They made a call for proposals, solicited applications, evaluated them, and selected winners for their Spring 2021 purchase. All public materials are available on GitHub. They received 26 submissions. We included 23 (88%) for our analyses.

We excluded one proposal that did not interact with the carbon cycle, and two proposals that presented broad theoretical pathways for carbon removal rather than a concrete and immediate offer.

Read our article on insights from evaluating these projects.

Microsoft 2021

In early 2020, Microsoft announced a commitment to purchase carbon removal. They made a call for proposals, solicited applications, evaluated them, and selected winners for their 2021 purchase. All public materials are available as a CSV file. They received 189 submissions. We included 162 (86%) for our analysis, due to incomplete or missing data.

We excluded 9 proposals that specified 0 tCO₂ offered volume, which made the project invalid as a proposal for carbon removal from the perspective of our analysis. We excluded 16 proposals that did not provide enough data to tell what activities led to the claimed carbon benefits. Some of these proposals indicated more complete information in confidential attachments which we did not view. We also excluded one renewable energy proposal, and one apparent double submission.

Microsoft’s RFP did not systematically surface life cycle analysis or price data in public sections of the application process. Therefore, most proposals from this source have N/As for negativity and price.

Read our article on insights from evaluating these projects.

Stripe 2020

In the spring of 2020 Stripe announced a commitment to purchase carbon removal. They made a call for proposals, solicited applications using this form, evaluated them, and selected winners for their 2020 purchase. All public materials are available on Github. They received 24 submissions. We included all 24 (100%) for our analyses.

Read our article on insights from evaluating these projects.

Back
Methods
Descriptions of our metrics and notes on each carbon removal project we have analyzed. For more on this work read our articles on what we learned analyzing proposals submitted to Stripe in 2020 , Microsoft in 2021, or Stripe in 2021. If you have questions or want to get in touch. check out the feedback section.

Sources

We develop this database by analyzing public proposals for carbon dioxide removal.

Thus far, we have obtained proposals from calls for carbon dioxide removal procurement, e.g. from corporations looking to purchase carbon removal. In principle we could obtain proposals from other sources (e.g. directly from projects or public processes), and we may explore this in the future. Repeated proposals from the same applicant are listed and analyzed separately.

While all proposals in this database claim to offer carbon removal, we do our best to surface the mechanisms underlying the proposal. Some projects exclusively perform carbon removal. Some include a component of avoided emissions. Some are exclusively avoided emissions at the moment, but could be part of a carbon removal system in the future. (Read our explainer for more on the difference between removal and avoided emissions).

Our analysis is based exclusively on public materials, including project proposals, public websites, registry listings, published literature, etc. In some cases we obtain early access to public proposals to get an early start on our analysis and make our reports as timely as possible. In cases where projects provided confidential information to prospective buyers alongside their public proposals, we avoid exposure to confidential information to the best of our ability, and do not incorporate it into our reports.

Below is a brief overview of our current primary sources.

Stripe 2021

In sprint 2021, Stripe ran a new round of carbon removal purchases. CarbonPlan collaborated with Stripe to design a new, open source carbon removal application. They made a call for proposals, solicited applications, evaluated them, and selected winners for their Spring 2021 purchase. All public materials are available on GitHub. They received 26 submissions. We included 23 (88%) for our analyses.

We excluded one proposal that did not interact with the carbon cycle, and two proposals that presented broad theoretical pathways for carbon removal rather than a concrete and immediate offer.

Read our article on insights from evaluating these projects.

Microsoft 2021

In early 2020, Microsoft announced a commitment to purchase carbon removal. They made a call for proposals, solicited applications, evaluated them, and selected winners for their 2021 purchase. All public materials are available as a CSV file. They received 189 submissions. We included 162 (86%) for our analysis, due to incomplete or missing data.

We excluded 9 proposals that specified 0 tCO₂ offered volume, which made the project invalid as a proposal for carbon removal from the perspective of our analysis. We excluded 16 proposals that did not provide enough data to tell what activities led to the claimed carbon benefits. Some of these proposals indicated more complete information in confidential attachments which we did not view. We also excluded one renewable energy proposal, and one apparent double submission.

Microsoft’s RFP did not systematically surface life cycle analysis or price data in public sections of the application process. Therefore, most proposals from this source have N/As for negativity and price.

Read our article on insights from evaluating these projects.

Stripe 2020

In the spring of 2020 Stripe announced a commitment to purchase carbon removal. They made a call for proposals, solicited applications using this form, evaluated them, and selected winners for their 2020 purchase. All public materials are available on Github. They received 24 submissions. We included all 24 (100%) for our analyses.

Read our article on insights from evaluating these projects.